WorldWideScience

Sample records for terrain evaluation

  1. Evaluating Terrain Irregularity by Robot Posture

    Directory of Open Access Journals (Sweden)

    Tomas Luneckas

    2011-08-01

    Full Text Available A method that allows evaluate the terrain irregularity by a robot posture is presented in this paper. A necessity to evaluate terrain irregularity is pointed out. Description of irregular terrain is given. A possibility to evaluate terrain irregularity by feet coordinate standard deviation is proposed. When deviation is σ = 0, all robots are in one plane. Bigger σ the more robot legs are scattered, meaning robot is walking in irregular terrain. A method to evaluate robot horizontality according to terrain by position of three planes is introduced.Article in Lithuanian

  2. Evaluation of terrain geomorphometric characteristics for ground clearance charts production

    Directory of Open Access Journals (Sweden)

    Mirko A. Borisov

    2011-01-01

    Full Text Available Geomorphometric exploration applied in the military terrain analysis is based on the GIS methodology of spatial analyses and is related primarily to military terrain analyses. It includes relief assessment aiming at producing ground clearance charts for the analysis of terrain maneuverability and its deployment, cover and concealment possibilities. An evaluation analysis of geomorphological parameters was performed for the Avala test area using a few terrain parameters (visibility, terrain aspect and slope as well as some terrain qualitative categories (e.g. vegetation density. Terrain slope Slope and aspect are morphometric terrain parameters that can be derived directly from the DTM using some GIS operations. Slope is the first derivative of a surface and has both magnitude and direction. Slope is perhaps the most important aspect of the surface form, since surfaces are formed completely of slopes, and slope angles control the gravitational force available for geomorphic work. Mathematically, the tangent of the slope angle is the first derivative of altitude, and it is a tangent or percent slope as this surface parameter is generally referred to. Slope is defined at each point as the slope of a plane tangent to the surface at that point. In practice, however, slope is generally measured over a finite distance, especially when data are obtained from a contour map. Terrain aspect Aspect is also the first derivative of a surface and has both magnitude and direction. The term aspect is defined as the direction of the biggest slope vector on the tangent plane projected onto the horizontal plane. Aspect is the bearing (or azimuth of the slope direction, and its angle ranges from 0 to 360°. Analyses of terrain slope and ground clearance for military forces The analysis of land assessment of the Avala test area included the definition of relief categories in relation to cover and concealment purposes with the aim to include the geomorphological basis

  3. Digital terrain model evaluation and computation of the terrain correction and indirect effect in South America

    Directory of Open Access Journals (Sweden)

    Denizar Blitzkow

    2009-12-01

    Full Text Available The main objectives of this paper are to compare digital terrain models, to show the generated models for South America and to present two applications. Shuttle Radar Topography Mission (SRTM produced the most important and updated height information in the world. This paper addresses the attention to comparisons of the following models: SRTM3, DTM2002, GLOBE, GTOPO30, ETOPO2 and ETOPO5, at the common points of the grid. The comparisons are limited by latitudes 60º S and 25 º N and longitudes 100 º W and 25 º W. All these data, after some analysis, have been used to create three models for South America: SAM_1mv1, SAM_1mv2 (both of 1' grid spacing and SAM_30s (30" grid spacing. Besides this effort, the three models as well as STRM were evaluated using Bench Marks (BM in Brazil and Argentina. This paper also shows two important geodesy and geophysics applications using the SAM_1mv1: terrain correction (one of the reductions applied to the gravity acceleration and indirect effect (a consequence of the reduction of the external mass to the geoid. These are important at Andes for a precise geoid computation.Los objetivos principales de este documento son comparar modelos digitales del continente; enseñar los modelos generados para Sudamérica y presentar dos aplicaciones. Shuttle Radar Topography Mission (SRTM produjo la información más importante y más actualizada de las altitudes del mundo. Este trabajo centra su atención en las comparaciones de los modelos siguientes: SRTM3, DTM2002, GLOBO, GTOPO30, ETOPO2 y ETOPO5, en los puntos comunes de la rejilla. Las comparaciones son limitadas por las latitudes 60º S y 25 º N y longitudes 100 º W y 25 º W. Todos estos datos, después de los análisis, se han utilizado para crear tres modelos para Sudamérica: SAM_1mv1, SAM_1mv2 (1' de espaciamiento de la rejilla y SAM_30s (30" de espaciamiento de la rejilla. Los tres modelos bien como el STRM fueron evaluados usando puntos de referencia de

  4. Evaluation of ERA-Interim precipitation data in complex terrain

    Science.gov (United States)

    Gao, Lu; Bernhardt, Matthias; Schulz, Karsten

    2013-04-01

    Precipitation controls a large variety of environmental processes, which is an essential input parameter for land surface models e.g. in hydrology, ecology and climatology. However, rain gauge networks provides the necessary information, are commonly sparse in complex terrains, especially in high mountainous regions. Reanalysis products (e.g. ERA-40 and NCEP-NCAR) as surrogate data are increasing applied in the past years. Although they are improving forward, previous studies showed that these products should be objectively evaluated due to their various uncertainties. In this study, we evaluated the precipitation data from ERA-Interim, which is a latest reanalysis product developed by ECMWF. ERA-Interim daily total precipitation are compared with high resolution gridded observation dataset (E-OBS) at 0.25°×0.25° grids for the period 1979-2010 over central Alps (45.5-48°N, 6.25-11.5°E). Wet or dry day is defined using different threshold values (0.5mm, 1mm, 5mm, 10mm and 20mm). The correspondence ratio (CR) is applied for frequency comparison, which is the ratio of days when precipitation occurs in both ERA-Interim and E-OBS dataset. The result shows that ERA-Interim captures precipitation occurrence very well with a range of CR from 0.80 to 0.97 for 0.5mm to 20mm thresholds. However, the bias of intensity increases with rising thresholds. Mean absolute error (MAE) varies between 4.5 mm day-1 and 9.5 mm day-1 in wet days for whole area. In term of mean annual cycle, ERA-Interim almost has the same standard deviation of the interannual variability of daily precipitation with E-OBS, 1.0 mm day-1. Significant wet biases happened in ERA-Interim throughout warm season (May to August) and dry biases in cold season (November to February). The spatial distribution of mean annual daily precipitation shows that ERA-Interim significant underestimates precipitation intensity in high mountains and northern flank of Alpine chain from November to March while pronounced

  5. A new method for determination of most likely landslide initiation points and the evaluation of digital terrain model scale in terrain stability mapping

    Directory of Open Access Journals (Sweden)

    P. Tarolli

    2006-01-01

    Full Text Available This paper introduces a new approach for determining the most likely initiation points for landslides from potential instability mapped using a terrain stability model. This approach identifies the location with critical stability index from a terrain stability model on each downslope path from ridge to valley. Any measure of terrain stability may be used with this approach, which here is illustrated using results from SINMAP, and from simply taking slope as an index of potential instability. The relative density of most likely landslide initiation points within and outside mapped landslide scars provides a way to evaluate the effectiveness of a terrain stability measure, even when mapped landslide scars include run out zones, rather than just initiation locations. This relative density was used to evaluate the utility of high resolution terrain data derived from airborne laser altimetry (LIDAR for a small basin located in the Northeastern Region of Italy. Digital Terrain Models were derived from the LIDAR data for a range of grid cell sizes (from 2 to 50 m. We found appreciable differences between the density of most likely landslide initiation points within and outside mapped landslides with ratios as large as three or more with the highest ratios for a digital terrain model grid cell size of 10 m. This leads to two conclusions: (1 The relative density from a most likely landslide initiation point approach is useful for quantifying the effectiveness of a terrain stability map when mapped landslides do not or can not differentiate between initiation, runout, and depositional areas; and (2 in this study area, where landslides occurred in complexes that were sometimes more than 100 m wide, a digital terrain model scale of 10 m is optimal. Digital terrain model scales larger than 10 m result in loss of resolution that degrades the results, while for digital terrain model scales smaller than 10 m the physical processes responsible for triggering

  6. Evaluation of topographic index in relation to terrain roughness and ...

    Indian Academy of Sciences (India)

    are upslope area, topographic index, stream power index, radiation index .... flat areas. The effect of smoothening and dis- cretisation were closely related to local terrain characteristics. However, the assessment of the topographic index is very ...... case study of two protected areas in Himalayan foothills;. Biodiversity and ...

  7. Evaluating planetary digital terrain models-The HRSC DTM test

    Science.gov (United States)

    Heipke, C.; Oberst, J.; Albertz, J.; Attwenger, M.; Dorninger, P.; Dorrer, E.; Ewe, M.; Gehrke, S.; Gwinner, K.; Hirschmuller, H.; Kim, J.R.; Kirk, R.L.; Mayer, H.; Muller, Jan-Peter; Rengarajan, R.; Rentsch, M.; Schmidt, R.; Scholten, F.; Shan, J.; Spiegel, M.; Wahlisch, M.; Neukum, G.

    2007-01-01

    The High Resolution Stereo Camera (HRSC) has been orbiting the planet Mars since January 2004 onboard the European Space Agency (ESA) Mars Express mission and delivers imagery which is being used for topographic mapping of the planet. The HRSC team has conducted a systematic inter-comparison of different alternatives for the production of high resolution digital terrain models (DTMs) from the multi look HRSC push broom imagery. Based on carefully chosen test sites the test participants have produced DTMs which have been subsequently analysed in a quantitative and a qualitative manner. This paper reports on the results obtained in this test. ?? 2007 Elsevier Ltd. All rights reserved.

  8. Biomechanic evaluation of upper-extremity symmetry during manual wheelchair propulsion over varied terrain.

    Science.gov (United States)

    Hurd, Wendy J; Morrow, Melissa M; Kaufman, Kenton R; An, Kai-Nan

    2008-10-01

    To evaluate upper-extremity symmetry during wheelchair propulsion across multiple terrain surfaces. Case series. A biomechanics laboratory and the general community. Manual wheelchair users (N=12). Not applicable. Symmetry indexes for the propulsion moment, total force, tangential force, fractional effective force, time-to-peak propulsion moment, work, length of push cycle, and power during wheelchair propulsion over outdoor and indoor community conditions, and in laboratory conditions. Upper-extremity asymmetry was present within each condition. There were no differences in the magnitude of asymmetry when comparing laboratory with indoor community conditions. Outdoor community wheelchair propulsion asymmetry was significantly greater than asymmetry measured during laboratory conditions. Investigators should be aware that manual wheelchair propulsion is an asymmetrical act, which may influence interpretation when data is collected from a single limb or averaged for both limbs. The greater asymmetry identified during outdoor versus laboratory conditions emphasizes the need to evaluate wheelchair biomechanics in the user's natural environment.

  9. Evaluation of skiing and snowboarding injuries sustained in terrain parks versus traditional slopes.

    Science.gov (United States)

    Brooks, M Alison; Evans, Michael D; Rivara, Frederick P

    2010-04-01

    This study compares skiing and snowboarding injuries in terrain parks versus slopes at two ski areas, 2000-05. A total of 3953 (26.7%) injuries occurred in terrain parks, predominantly among young male snowboarders. Terrain park injuries were more likely to be severe, involving head (RR 1.31, 95% CI 1.16 to 1.48) or back (RR 1.96, 95% CI 1.67 to 2.29).

  10. Biomechanic Evaluation of Upper-Extremity Symmetry Manual Wheelchair Propulsion Over Varied Terrain

    Science.gov (United States)

    Hurd, Wendy J.; Morrow, Melissa M.; Kaufman, Kenton R.; An, Kai-Nan

    2014-01-01

    Objective To evaluate upper-extremity symmetry during wheelchair propulsion across multiple terrain surfaces. Design Case series. Setting A biomechanics laboratory and the community. Participants Manual wheelchair users (N=12). Interventions Not applicable. Main Outcome Measures Symmetry indexes for the propulsion moment, total force, tangential force, fractional effective force, time-to-peak propulsion moment, work, length of push cycle, and power during wheelchair propulsion over outdoor and indoor community conditions, and in conditions. Results Upper-extremity asymmetry was present within each condition. There were no differences in the magnitude of asymmetry when comparing laboratory with indoor community conditions. Outdoor community wheelchair propulsion asymmetry was significantly greater than asymmetry measured during laboratory conditions. Conclusions Investigators should be aware that manual wheelchair propulsion is an asymmetrical act, which may influence interpretation when data is collected from a single limb or averaged for both limbs. The greater asymmetry identified during outdoor versus laboratory conditions the emphasizes need to evaluate wheelchair biomechanics in the user’s natural environment. PMID:18929029

  11. Performance and evaluation of a coupled prognostic model TAPM over a mountainous complex terrain industrial area

    Science.gov (United States)

    Matthaios, Vasileios N.; Triantafyllou, Athanasios G.; Albanis, Triantafyllos A.; Sakkas, Vasileios; Garas, Stelios

    2017-04-01

    Atmospheric modeling is considered an important tool with several applications such as prediction of air pollution levels, air quality management, and environmental impact assessment studies. Therefore, evaluation studies must be continuously made, in order to improve the accuracy and the approaches of the air quality models. In the present work, an attempt is made to examine the air pollution model (TAPM) efficiency in simulating the surface meteorology, as well as the SO2 concentrations in a mountainous complex terrain industrial area. Three configurations under different circumstances, firstly with default datasets, secondly with data assimilation, and thirdly with updated land use, ran in order to investigate the surface meteorology for a 3-year period (2009-2011) and one configuration applied to predict SO2 concentration levels for the year of 2011.The modeled hourly averaged meteorological and SO2 concentration values were statistically compared with those from five monitoring stations across the domain to evaluate the model's performance. Statistical measures showed that the surface temperature and relative humidity are predicted well in all three simulations, with index of agreement (IOA) higher than 0.94 and 0.70 correspondingly, in all monitoring sites, while an overprediction of extreme low temperature values is noted, with mountain altitudes to have an important role. However, the results also showed that the model's performance is related to the configuration regarding the wind. TAPM default dataset predicted better the wind variables in the center of the simulation than in the boundaries, while improvement in the boundary horizontal winds implied the performance of TAPM with updated land use. TAPM assimilation predicted the wind variables fairly good in the whole domain with IOA higher than 0.83 for the wind speed and higher than 0.85 for the horizontal wind components. Finally, the SO2 concentrations were assessed by the model with IOA varied from 0

  12. Ergonomic factors and production target evaluation in eucalyptus timber harvesting operations in mountainous terrains.

    Science.gov (United States)

    de Souza, Amaury Paulo; Minette, Luciano José; Sanches, André Luis Petean; da Silva, Emília Pio; Rodrigues, Valéria Antônia Justino; de Oliveira, Luciana Aparecida

    2012-01-01

    There are several forest operations involved in Eucalyptus timber harvesting. This study was carried out during brush-cutting; tree felling, bucking, delimbing, piling and manual extraction operations, with the following objectives: a) analyzing, ergonomically, two systems of brush-cutting: one manual and the other semi-mechanized, using two different machines; b) ergonomically evaluating three different brands of pruner machines used in delimbing felled trees. c) determining the feasible target of productivity as a function of ergonomic factors relevant to establish the time of resting pauses for workers in manual and semi-mechanized timber harvesting systems in mountainous terrain. Brush-cutting, either manual or semimechanized, is an activity carried out prior to timber harvesting. It is usually a hard work, with low productivity when compared with mechanized systems. Pruner machines have been used by forest companies, due to the great possibilities to improve productivity, quality and the health of workers. Ergonomics is a discipline that promotes the adequacy of work to the physical and mental characteristics of human beings, seeking to design production systems and products considering relevant aspects, including social, organizational and environmental factors. Companies should consider the ergonomic factor in the determination of daily worker production targets.

  13. Evaluating the Use of an Object-Based Approach to Lithological Mapping in Vegetated Terrain

    Directory of Open Access Journals (Sweden)

    Stephen Grebby

    2016-10-01

    Full Text Available Remote sensing-based approaches to lithological mapping are traditionally pixel-oriented, with classification performed on either a per-pixel or sub-pixel basis with complete disregard for contextual information about neighbouring pixels. However, intra-class variability due to heterogeneous surface cover (i.e., vegetation and soil or regional variations in mineralogy and chemical composition can result in the generation of unrealistic, generalised lithological maps that exhibit the “salt-and-pepper” artefact of spurious pixel classifications, as well as poorly defined contacts. In this study, an object-based image analysis (OBIA approach to lithological mapping is evaluated with respect to its ability to overcome these issues by instead classifying groups of contiguous pixels (i.e., objects. Due to significant vegetation cover in the study area, the OBIA approach incorporates airborne multispectral and LiDAR data to indirectly map lithologies by exploiting associations with both topography and vegetation type. The resulting lithological maps were assessed both in terms of their thematic accuracy and ability to accurately delineate lithological contacts. The OBIA approach is found to be capable of generating maps with an overall accuracy of 73.5% through integrating spectral and topographic input variables. When compared to equivalent per-pixel classifications, the OBIA approach achieved thematic accuracy increases of up to 13.1%, whilst also reducing the “salt-and-pepper” artefact to produce more realistic maps. Furthermore, the OBIA approach was also generally capable of mapping lithological contacts more accurately. The importance of optimising the segmentation stage of the OBIA approach is also highlighted. Overall, this study clearly demonstrates the potential of OBIA for lithological mapping applications, particularly in significantly vegetated and heterogeneous terrain.

  14. Human Robotic Systems (HRS): Extreme Terrain Mobility Element

    Data.gov (United States)

    National Aeronautics and Space Administration — During 2014, the Extreme Terrain Mobility project element is developing five technologies:Exoskeleton Development for ISS EvaluationExtreme Terrain Mobility...

  15. Filling Terrorism Gaps: VEOs, Evaluating Databases, and Applying Risk Terrain Modeling to Terrorism

    Energy Technology Data Exchange (ETDEWEB)

    Hagan, Ross F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-08-29

    This paper aims to address three issues: the lack of literature differentiating terrorism and violent extremist organizations (VEOs), terrorism incident databases, and the applicability of Risk Terrain Modeling (RTM) to terrorism. Current open source literature and publicly available government sources do not differentiate between terrorism and VEOs; furthermore, they fail to define them. Addressing the lack of a comprehensive comparison of existing terrorism data sources, a matrix comparing a dozen terrorism databases is constructed, providing insight toward the array of data available. RTM, a method for spatial risk analysis at a micro level, has some applicability to terrorism research, particularly for studies looking at risk indicators of terrorism. Leveraging attack data from multiple databases, combined with RTM, offers one avenue for closing existing research gaps in terrorism literature.

  16. Evaluation of Sedimentary and Terrain Parameters from MARDI Camera Imaging and Stereogrammetry at Gale Crater

    Science.gov (United States)

    Minitti, M. E.; Garvin, J. B.; Yingst, R. A.; Maki, J.

    2014-12-01

    The Mars Descent Imager (MARDI) provides mm-resolution imaging of an ~0.92 m by 0.64 cm patch of the Martian surface beneath the rover. Since Sol 310, MARDI has acquired images under twilight illumination to optimize image quality for quantitative sedimentology analysis. This imaging, carried out after each rover drive, permits systematic measurement of clast size distribution, inter-clast spacing distribution, and surface areal coverage. Sedimentological parameters derived from these observations include clast sorting (mean/var of size) and other characteristics related to transport mechanisms or in-place weathering. Measured surface parameters (e.g., clast sorting) can be correlated with surface units qualitatively defined (e.g., smooth, rocky, outcrop) in images obtained by HiRISE, MSL Mastcam and MSL Navcam. In addition, a preliminary longitudinal analysis has been conducted to examine possible source regions for the bulk of the gravels by correlating sedimentary parameters with distance from either Peace Valles or Mt. Sharp, with evidence of trends associated with inter-clast spacing. Sets of stereo MARDI images that allow the creation of high vertical precision (±2 mm) digital elevation models (DEMs) have also been acquired via two techniques. First, MARDI images taken at each step of comprehensive wheel imaging activities yield 5 MARDI images with ~50% overlap. Second, two MARDI sidewalk video imaging mode (SVIM) experiments yielded a continuous set of images during a rover drive with 75-82% overlap. DEMs created via either technique can be used to quantify terrain properties and measure clast cross-sectional shapes. The microtopographic properties of the Sol 651 surface (e.g., mean/sigma of local elevation and slopes) and its sub-cm texture as measured in the SVIM-derived DEM are consistent with the characterization of the terrain as smooth with few rocks >20 cm. Characterization of the Sol 691 surface as rockier than the Sol 651 surface is supported by a

  17. Evaluation of Vertical Electrical Sounding Method for Groundwater Development in Basement Complex Terrain of West-Central Nigeria

    Directory of Open Access Journals (Sweden)

    A. K. Olawuyi

    2013-12-01

    Full Text Available This research evaluated the Vertical Electrical Sounding (VES method of groundwater development in the Basement Complex terrain of West Central Nigeria. It was aimed at verifying the reliability of VES in differentiating lithologies, predicting the depth to basement and probably, aquifer in groundwater development. In doing this, the Schlumberger electrode configuration was employed in the surveys while partial curve matching and computer iteration techniques were used to interpret the curves obtained. In all, seventy three VES were carried out and fourteen boreholes constructed. Comparison was made between the predicted depth to basement from VES and the actual depth from the drilling log. A linear relationship between the actual depth and that predicted by VES was established with coefficient of determination of 0.94 confirming the reliability of the VES method. None of the boreholes drilled was abortive.

  18. Model evaluation of RIMPUFF within complex terrain using an 41Ar radiological dataset

    DEFF Research Database (Denmark)

    Dyer, Leisa L.; Astrup, Poul

    2012-01-01

    The newly updated atmospheric dispersion model RIMPUFF is evaluated using routine releases of 41Ar from the former HIFAR research reactor located in Sydney, Australia. A large number of 41Ar measurements from a network of environmental gamma detectors are used to evaluate the model under a range...

  19. Alliance Helps States Map New Terrain in Educator Evaluation. REL West Research Digest

    Science.gov (United States)

    Regional Educational Laboratory West, 2014

    2014-01-01

    About five years ago, states across the country took on the huge, complex task of developing and implementing new systems to evaluate teacher and principal performance in public schools. In response to a federal mandate aimed at improving student achievement, especially in the lowest performing schools, state boards of education drafted high-level…

  20. Surface Wind Regionalization over Complex Terrain: Evaluation and Analysis of a High-Resolution WRF Simulation

    NARCIS (Netherlands)

    Jiménez, P.A.; González-Rouco, J.F.; García-Bustamante, E.; Navarro, J.; Montávez, J.P.; Vilà-Guerau de Arellano, J.; Dudhia, J.; Muñoz-Roldan, A.

    2010-01-01

    This study analyzes the daily-mean surface wind variability over an area characterized by complex topography through comparing observations and a 2-km-spatial-resolution simulation performed with the Weather Research and Forecasting (WRF) model for the period 1992–2005. The evaluation focuses on the

  1. Evaluation of consecutive skylines yarding and gravity skidding systems in primary forest transportation on steep terrain.

    Science.gov (United States)

    Gumus, Selcuk; Acar, H Hulusi

    2010-01-01

    This investigation evaluates two primary forest transportation systems, consecutive skyline yarding system integrated with two different types of skyline yarding systems and the gravity skidding system, considering technical, economical and environmental aspects. The results indicated that the productivity of consecutive skyline yarding system was 4.97 m3 hr(-1), while the productivity of the gravity skidding system was 0.74 m3 hr(-1). The unit costs of these primary transportation systems were found to be $5.98 and $51.28 m3, respectively. Besides, the gravity skidding system caused more damages on skidded logs, residual trees, and forest soil than that of consecutive skyline yarding system. It was also indicated that two different skyline yarding systems produced definite and different average yarding distances and technical capacities, which negatively affected the overall performance of the consecutive skyline yarding system. Therefore, different types of skyline yarding systems should not be integrated into the consecutive yarding systems.

  2. Model-Based Method for Terrain-Following Display Design

    Science.gov (United States)

    1989-06-15

    A model-based method for terrain-following display design and evaluation is described. The basic approach centers on the use of a pilot/ vehicle...data. Terrain-following, Mathematical modeling, Aircraft display design , Optimal control model.

  3. Evaluation of the effect of the sub-kilometric scale terrain heterogeneities in the surface energy budget through observations and numerical modelling

    Science.gov (United States)

    Cuxart, Joan; Wrenger, Burkhard; Antònia Jiménez, M.; Dünnermann, Jens; Reuder, Joachim; Jonassen, Marius; Martínez, Daniel; Conangla, Laura; Lothon, Marie

    2014-05-01

    The point measurements of environmental variables, including the meteorological weather stations for operational or research purposes, are very rarely located in homogeneous terrain. However the assumption of homogeneity is customarily made. Structured local terrain variations may induce circulations which are not random (as is assumed for the turbulence eddies), and their effects might be treated as advection contributions in the equations of the variables of interest. In this work we explore if the imbalances of the surface energy equation can be correlated with the well-documented variations on the soil and vegetation characteristics for the site-1 of the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) campaign, held in summer 2011 on the northern foothills of the Pyrenees. Observational evaluation of surface heterogeneities and the corresponding air variablility was made through direct measurement and remote sensing. For air and surface temperature heterogeneities, horizontal transsects and vertical profiles were made by a remotely-controlled multicopter below 50 m and with a small UAV above. On the other hand a simulation with a horizontal resolution of 80 m has been made for an area of 16 km x 16 km centered around site-1 over the Lannemezan plateau. The sub-kilometric circulations as seen by the model are explored and the statistics compared to those of a lower resolution simulation and to the ones computed experimentally for the site.

  4. DIORAMA Earth Terrain Model

    Energy Technology Data Exchange (ETDEWEB)

    Werley, Kenneth Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-10

    When simulating near-surface nuclear detonations, the terrain of the Earth can have an effect on the observed outputs. The critical parameter is called the “height of burst”. In order to model the effect of terrain on the simulations we have incorporated data from multiple sources to give 9 km resolution data with global coverage.

  5. Evaluation of the TMPA-3B42 precipitation product using a high-density rain gauge network over complex terrain in northeastern Iberia

    KAUST Repository

    El Kenawy, Ahmed M.

    2015-08-29

    The performance of the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA)-3B42 version 7 product is assessed over north-eastern Iberia, a region with considerable topographical gradients and complexity. Precipitation characteristics from a dense network of 656 rain gauges, spanning the period from 1998 to 2009, are used to evaluate TMPA-3B42 estimates on a daily scale. A set of accuracy estimators, including the relative bias, mean absolute error (MAE), root mean square error (RMSE) and Spearman coefficient was used to evaluate the results. The assessment indicates that TMPA-3B42 product is capable of describing the seasonal characteristics of the observed precipitation over most of the study domain. In particular, TMPA-3B42 precipitation agrees well with in situ measurements, with MAE less than 2.5mm.day-1, RMSE of 6.4mm.day-1 and Spearman correlation coefficients generally above 0.6. TMPA-3B42 provides improved accuracies in winter and summer, whereas it performs much worse in spring and autumn. Spatially, the retrieval errors show a consistent trend, with a general overestimation in regions of low altitude and underestimation in regions of heterogeneous terrain. TMPA-3B42 generally performs well over inland areas, while showing less skill in the coastal regions. A set of skill metrics, including a false alarm ratio [FAR], frequency bias index [FBI], the probability of detection [POD] and threat score [TS], is also used to evaluate TMPA performance under different precipitation thresholds (1, 5, 10, 25 and 50mm.day-1). The results suggest that TMPA-3B42 retrievals perform well in specifying moderate rain events (5-25mm.day-1), but show noticeably less skill in producing both light (<1mm.day-1) and heavy rainfall thresholds (more than 50mm.day-1). Given the complexity of the terrain and the associated high spatial variability of precipitation in north-eastern Iberia, the results reveal that TMPA-3B42 data provide an

  6. Comparison between two diagnostic models of atmospheric flow above complex terrain : the evaluation of the wind potential of La Ventosa

    Energy Technology Data Exchange (ETDEWEB)

    Milanesi, M.; Cassola, F.; Burlando, M.; Ratto, C.F. [Genoa Univ., Genoa (Italy). Dept. of Physics

    2008-07-01

    Interest in wind energy production has increased in recent years due to improvements in wind turbine technology and the growing need for energy production by renewable sources. One of the most important issues to deal with is the choice of an adequate site. Therefore, wind energy researchers deal directly with statistical properties of wind, coming from in-situ measurements. Different methodologies have been developed to study and define the wind climate of a particular region, starting from measured data. Diagnostic wind field models can simulate wind fields and determine the best sites for wind turbine arrays. This study compared the performance of 2 diagnostic atmospheric flow models, notably the Wind Atlas Analysis and Application Program (WAsP) and the Wind-field Interpolation by Non-Divergent Schemes (WINDS) model. The models are based on two very different approaches. The Navier-Stokes equations of motion are considered in the WAsP model, but only the equation of mass conservation is taken into account in the WINDS model. The models were used to analyze the available wind data in the region of La Ventosa, Mexico where some of the world's highest wind resources are available. Both the models and the methodologies proved to be suitable for managing the wind climatology of this region. A bi-modal non-directional frequency distribution of the wind speed exists due to the presence of two distinct wind regimes during winter and summer respectively. The comparison between the mean wind speeds simulated by the models showed that the values were very similar over the least complex terrain, while the discrepancies increase in the highest and steepest areas. In general, WAsP predicted lower values over valleys and depressed areas, and higher values over ridges. This was due to the sheltering effect of the mountain ridges north-west and north-east of the anemometer station. 30 refs., 6 figs.

  7. TERRAIN, UNION PARISH, LOUSIANA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  8. TERRAIN, KENDALL COUNTY, TEXAS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. TERRAIN, DELAWARE COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. TERRAIN, CEDAR COUNTY, IA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  11. TERRAIN, Norfolk County, Massachusetts

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  12. TERRAIN, DARKE COUNTY, OH

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. TERRAIN, DAWSON COUNTY, NE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. TERRAIN, Hampden County, Massachusetts

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  15. TERRAIN, RICE COUNTY, MN

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. TERRAIN, WRIGHT COUNTY, IA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  17. TERRAIN, MERCER COUNTY, OHIO

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. TERRAIN, HANCOCK COUNTY, OH

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  19. TERRAIN, JEFFERSON COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  20. TERRAIN, FULTON COUNTY, OH

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. TERRAIN, Bennington County, Vermont

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  2. TERRAIN, SNOHOMISH COUNTY, WASHINGTON

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  3. TERRAIN, TROUSDALE COUNTY, TENNESSEE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  4. TERRAIN, WAYNE COUNTY, TENNESSEE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. TERRAIN, BARNSTABLE COUNTY, MASSACHUSETTS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  6. TERRAIN, POTTER COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that were used to create...

  7. TERRAIN, Northampton COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that were used to create...

  8. Terrain Park Injuries

    Directory of Open Access Journals (Sweden)

    Moffat, Craig

    2009-11-01

    Full Text Available Background: This study examined demographics, injury pattern, and hospital outcome in patients injured in winter resort terrain parks.Methods: The study included patients >12 years of age who presented to a regional trauma center with an acute injury sustained at a winter resort. Emergency department (ED research assistants collected patient injury and helmet use information using a prospectively designed questionnaire. ED and hospital data were obtained from trauma registry and hospital records.Results: Seventy-two patients were injured in a terrain park, and 263 patients were injured on non-terrain park slopes. Patients injured in terrain parks were more likely to be male [68/72 (94% vs. 176/263 (67%, p<0.0001], younger in age [23 ± 7 vs. 36 ± 17, p<0.0001], live locally [47/72 (65% vs. 124/263 (47%, p=0.006], use a snowboard [50/72 (69% vs. 91/263 (35%, p<0.0001], hold a season pass [46/66 (70% vs. 98/253 (39%, p<0.0001], and sustain an upper extremity injury [29/72 (40% vs. 52/263 (20%, p<0.001] when compared to patients injured on non-terrain park slopes. There were no differences between the groups in terms of EMS transport to hospital, helmet use, admission rate, hospital length of stay, and patients requiring specialty consultation in the ED.Conclusions: Patients injured in terrain parks represent a unique demographic within winter resort patrons. Injury severity appears to be similar to those patients injured on non-terrain park slopes.[West J Emerg Med. 2009;10(4:257-262.

  9. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  10. Digital Data Digest, Volume 5, Number 2, Fall 1996. Army and NIMA Work with Warfighters to Evaluate High-Resolution Digital Terrain Data Bases

    National Research Council Canada - National Science Library

    1996-01-01

    .... This exercise brought together Army, Marine Corps and Special Operations experts to hike, climb, and crawl through the cinder-block buildings of the McKenna Military Operations on Urban Terrain (MOUT...

  11. Flow on noisy terrains

    DEFF Research Database (Denmark)

    Tsirogiannis, Konstantinos; Haverkort, Herman

    2011-01-01

    Computing watersheds on triangulated terrain models in a robust manner is a difficult task as it is sensitive to noise that appears in the elevation values of the input. This is amplified by the existence of many very small watersheds (corresponding to spurious minima) that obscure the overall hy...... to use a robust flow model together with exact arithmetic....

  12. Good terrain geometry, cheap!

    Energy Technology Data Exchange (ETDEWEB)

    Duchaineau, M. [Los Alamos National Lab., NM (United States)]|[Lawrence Livermore National Lab., CA (United States); Wolinsky, M.; Sigeti, D.E. [Los Alamos National Lab., NM (United States)] [and others

    1997-04-01

    Real-time terrain rendering for interactive visualization remains a demanding task. We present a novel algorithm with several advantages over previous methods: our method is unusually stingy with polygons yet achieves real-time performance and is scalable to arbitrary regions and resolutions. The method provides a continuous terrain mesh of specified triangle count having provably minimum error in restricted but reasonably general classes of permissible meshes and error metrics. Our method provides an elegant solution to guaranteeing certain elusive types of consistency in scenes produced by multiple scene generators which share a common finest-resolution database but which otherwise operate entirely independently. This consistency is achieved by exploiting the freedom of choice of error metric allowed by the algorithm to provide, for example, multiple exact lines-of-sight in real-time. Our methods rely on an off-line pre-processing phase to construct a multi-scale data structure consisting of triangular terrain approximations enhanced ({open_quotes}thickened{close_quotes}) with world-space error information. In real time, this error data is efficiently transformed into screen-space where it is used to guide a greedy top-down triangle subdivision algorithm which produces the desired minimal error continuous terrain mesh. Our algorithm has been implemented and it operates at real-time rates.

  13. Navigating Hypermasculine Terrains

    DEFF Research Database (Denmark)

    Henriksen, Ann-Karina Eske

    2017-01-01

    imposed by a street-based hypermasculine script. The analysis rests on an ethnographic study among 25 young Danish women aged 13 to 23 experienced in engaging in street-based physical violence. The study suggests that explorations of female tactics can provide a useful method of analysis for understanding...... female agency in (hyper)masculine social terrains....

  14. Evaluating the effect of spatial subsetting on subpixel unmixing methodology applied to ASTER over a hydrothermally altered terrain

    Science.gov (United States)

    Ayoobi, Iman; Tangestani, Majid H.

    2017-10-01

    This study investigates the effect of spatial subsets of Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) L1B visible-near infrared and short wave-infrared (VNIR-SWIR) data on matched filtering results at the central part of Kerman magmatic arc, where abundant porphyry copper deposits exist. The matched filtering (MF) procedure was run separately at sites containing hydrothermal minerals such as sericite, kaolinite, chlorite, and jarosite to map the abundances of these minerals on spatial subsets containing 100, 75, 50, and 25 percent of the original scene. Results were evaluated by comparing the matched filtering scores with the mineral abundances obtained by semi-quantitative XRD analysis of corresponding field samples. It was concluded that MF method should be applied to the whole scene prior to any data subsetting.

  15. Planialtimetric Accuracy Evaluation of Digital Surface Model (dsm) and Digital Terrain Model (dtm) Obtained from Aerial Survey with LIDAR

    Science.gov (United States)

    Cruz, C. B. M.; Barros, R. S.; Rabaco, L. M. L.

    2012-07-01

    It's noticed a significant increase in the development of orbital and airborne sensors that enable the extraction of three-dimensional data. Consequently, it's important the increment of studies about the quality of altimetric values derived from these sensors to verify if the improvements implemented in the acquisition of data may influence the results. In this context, as part of a larger project that aims to evaluate the accuracy of various sensors, this work aims to analysis the planialtimetric accuracy of DSM and DTM generated from an aerial survey with LIDAR, using as reference for the planimetric analysis of the orthophotos obtained. The project was developed for an area of São Sebastião city, located in the basin of the North Coast of São Paulo state. The area's relief is very steep, with a predominance of dense forest vegetation, typical of the Atlantic Forest. All points have been established in the field, with the use of GNSS of one frequency (L1) through static relative positioning, acquiring a minimum of 1,500 epochs, for a distance less than 20 km to the base. In this work it's considered the Brazilian standard specifications for classification of cartographic bases (PEC). The Brazilian company responsible for the aerial survey (LACTEC) gave the following products for analysis: point clouds in raw format (x, y, z) using orthometric heights; point clouds (first and last pulse) for each range of flight to verify systematic errors; DTM uniformly spaced, filtering small natural obstacles, buildings and vegetation, in Geotiff format; DSM also uniformly spaced, in Geotiff format; and the mosaic of georeferenced digital images. The analysis realized on products from the LIDAR indicated their adoption to the scales 1:2,000 (Class A for the orthophotos and Class B for the DTM) and 1:5,000 (class C for the DSM). There were no indications of trends in the results. The average error was 0.01 m. It's important that new areas with different topographic

  16. Stereo based Obstacle Detection with Uncertainty in Rough Terrain

    NARCIS (Netherlands)

    Mark, W. van der; Heuvel, J.C. van den; Groen, F.C.A.

    2007-01-01

    Autonomous robot vehicles that operate in offroad terrain should avoid obstacle hazards. In this paper we present a stereo vision based method that is able to cluster reconstructed terrain points into obstacles by evaluating their relative angles and distances. In our approach, constraints are

  17. T-transformation: traversability analysis for navigation on rugged terrain

    Science.gov (United States)

    Ye, Cang; Borenstein, Johann

    2004-09-01

    In order to maneuver autonomously on rough terrain, a mobile robot must constantly decide whether to traverse or circumnavigate terrain features ahead. This ability is called Obstacle Negotiation (ON). A critical aspect of ON is the so-called traversability analysis, which evaluates the level of difficulty associated with the traversal of the terrain. This paper presents a new method for traversability analysis, called T-transformation. It is implemented in a local terrain map as follows: (1) For each cell in the local terrain map, a square terrain patch is defined that symmetrically overlays the cell; (2) a plane is fitted to the data points in the terrain patch using a least-square approach and the slope of the least-squares plane and the residual of the fit are computed and used to calculate the Traversability Index (TI) for that cell; (3) after each cell is assigned a TI value, the local terrain map is transformed into a traversability map. The traversability map is further transformed into a traversability field histogram where each element represents the overall level of difficulty to move along the corresponding direction. Based on the traversability field histogram our reactive ON system then computes the steering and velocity commands to move the robot toward the intended goal while avoiding areas of poor traversability. The traversability analysis algorithm and the overall ON system were verified by extensive simulation. We verified our method partially through experiments on a Segway Robotics Mobility Platform (RMP), albeit only on flat terrain.

  18. Evaluation of different digital elevation models for analyzing drainage morphometric parameters in a mountainous terrain: a case study of the Supin?Upper Tons Basin, Indian Himalayas

    OpenAIRE

    Das, Sayantan; Patel, Priyank Pravin; Sengupta, Somasis

    2016-01-01

    Background With myriad geospatial datasets now available for terrain information extraction and particularly streamline demarcation, there arises questions regarding the scale, accuracy and sensitivity of the initial dataset from which these aspects are derived, as they influence all other parameters computed subsequently. In this study, digital elevation models (DEM) derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER V2), Shuttle Radar Topography Mission (SRTM...

  19. Evaluation of a spatial rainfall generator and an interpolation methods for the creation of future gridded data sets over complex terrains

    Science.gov (United States)

    Camera, Corrado; Bruggeman, Adriana; Hadjinicolaou, Panos; Michaelides, Silas; Lange, Manfred A.

    2015-04-01

    Space-time variability of precipitation plays a key role as a driver of many processes in different environmental fields like hydrology, ecology, biology, agriculture, and natural hazards. The objective of this study was to compare two approaches for statistical downscaling of precipitation from climate models. The study was applied to the island of Cyprus, an orographically complex terrain. The first approach makes use of a spatial temporal Neyman-Scott Rectangular Pulses (NSRP) model and a previously tested interpolation scheme (Camera et al., 2014). The second approach is based on the use of the single site NSRP model and a simplified gridded scheme based on scaling coefficients obtained from past observations. The rainfall generators were evaluated on the period 1980-2010. Both approaches were subsequently used to downscale three RCMs from the EU ENSEMBLE project to calculate climate projections (2020-2050). The main advantage of the spatial-temporal approach is that it allows creating spatially consistent daily maps of precipitation. On the other hand, due to the assumptions made using a stochastic generator based on homogeneous Poisson processes, it shows a smoothing out of all the rainfall statistics (except mean and variance) all over the study area. This leads to high errors when analyzing indices related to extremes. Examples are the number of days with rainfall over 50 mm (R50 - mean error 65%), the 95th percentile value of rainy days (RT95 - mean error 19%), and the mean annual rainfall recorded on days with rainfall above the 95th percentile (RA95 - mean error 22%). The single site approach excludes the possibility of using the created gridded data sets for case studies involving spatial connection between grid cells (e.g. hydrologic modelling), but it leads to a better reproduction of rainfall statistics and properties. The errors for the extreme indices are in fact much lower: 17% for R50, 4% for RT95, and 2% for RA95. Future projections show a

  20. Washboard Terrain on Pluto

    Science.gov (United States)

    Moore, Jeffrey M.; White, Oliver L.; Howard, Alan D.; Umurhan, Orkan M.; Schenk, Paul M.; Beyer, Ross A.; McKinnnon, William B.; Singer, Kelsi N.; Lauer, Tod R.; Cheng, Andrew F.; Young, Leslie; Stern, S. Alan; Weaver, Harold A.; Olkin, Catherine; Ennico, Kimberly; New Horizons Science Team

    2017-10-01

    Washboard texture or patterning consists of fields of parallel to sub-parallel ridges typically spaced ~1-2 km crest to crest and a few 100 m in amplitude (Fig. 4a in Moore et al., 2016, Science, 351, 1284-1293). For the most part, underlying topography can be easily discerned. We will refer to discrete, well-bounded patches of these landforms as Washboard Terrain (WT). WT is observed to occur along the rim, and just beyond the rim, of Sputnik basin from the West to NNW. Where it is seen in high-resolution data, it has clearly defined limits, beyond which it would be able to be seen if it were there. WT doesn’t occur at very low latitudes or very high latitudes (ranging from 22°N to 62°N). WT seems to occur most conspicuously on relatively level, gently sloping terrain. It is restricted to elevations between ~-2 km to area in which WT occurs is the sinuous valley network, which is suspected to have been formed, or at least substantially modified, by glaciation. WT also appears to occur mainly on an intermediate-albedo reddish material, where seen in enhanced color data. Where it occurs in level terrain, WT tends to trend ENE - there doesn’t seem to be a strong local control of its orientation in response to valley drainage directions. WT can display a greater range of orientations where it occurs in higher-relief (not higher elevation) settings such as spurs. WT appears superposed on very ancient landscapes, but is itself cratered locally by clusters of small (~1-3 km) craters, which may be secondaries. This implies that WT may be intermediate in age. Of several working hypotheses, we currently provisionally favor that WT may be akin to terrestrial recessional moraines (or de Geer moraines) associated with the retreat of a higher stand of N2 glaciation that once overfilled Sputnik basin. These putative moraine features may owe their spacing to superseasonal retreat on Milankovitch timescales of ~1 Ma. If this hypothesis has validity, then perhaps the

  1. Turbulence in complex terrain

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Jakob [Risoe National Lab., Wind Energy and Atmosheric Physics Dept., Roskilde (Denmark)

    1999-03-01

    The purpose of this work is to develop a model of the spectral velocity-tensor in neutral flow over complex terrain. The resulting equations are implemented in a computer code using the mean flow generated by a linear mean flow model as input. It estimates turbulence structure over hills (except on the lee side if recirculation is present) in the so-called outer layer and also models the changes in turbulence statistics in the vicinity roughness changes. The generated turbulence fields are suitable as input for dynamic load calculations on wind turbines and other tall structures and is under implementation in the collection of programs called WA{sup s}P Engineering. (au) EFP-97; EU-JOULE-3. 15 refs.

  2. Polygonal terrains on Mars

    Directory of Open Access Journals (Sweden)

    Pedro Pina

    2009-06-01

    Full Text Available The presence of water ice on Mars is well established. Some featureson the planet point to the occurrence of processes similar to those that take place in periglacial areas of Earth. One of the clues for this is the existence of small-scale polygonal terrains. In this paper, we present a methodology that aims at the automated identification of polygonal patterns on high-spatial resolution images of the surface of Mars. In the context of the research project TERPOLI, this step will be complemented with a full characterization, in both geometric and topological terms, of thenetworks detected. In this manner, we hope to collect data that will lead to a better understanding of the conditions of formation of the polygons, and of their temporal evolution; namely, we intend to identify different groups of polygons and to compare them with terrestrial examples.

  3. On characterizing terrain visibility graphs

    Directory of Open Access Journals (Sweden)

    William Evans

    2015-06-01

    Full Text Available A terrain is an $x$-monotone polygonal line in the $xy$-plane. Two vertices of a terrain are mutually visible if and only if there is no terrain vertex on or above the open line segment connecting them. A graph whose vertices represent terrain vertices and whose edges represent mutually visible pairs of terrain vertices is called a terrain visibility graph. We would like to find properties that are both necessary and sufficient for a graph to be a terrain visibility graph; that is, we would like to characterize terrain visibility graphs.Abello et al. [Discrete and Computational Geometry, 14(3:331--358, 1995] showed that all terrain visibility graphs are “persistent”. They showed that the visibility information of a terrain point set implies some ordering requirements on the slopes of the lines connecting pairs of points in any realization, and as a step towards showing sufficiency, they proved that for any persistent graph $M$ there is a total order on the slopes of the (pseudo lines in a generalized configuration of points whose visibility graph is $M$.We give a much simpler proof of this result by establishing an orientation to every triple of vertices, reflecting some slope ordering requirements that are consistent with $M$ being the visibility graph, and prove that these requirements form a partial order. We give a faster algorithm to construct a total order on the slopes. Our approach attempts to clarify the implications of the graph theoretic properties on the ordering of the slopes, and may be interpreted as defining properties on an underlying oriented matroid that we show is a restricted type of $3$-signotope.

  4. Hydrologic Terrain Processing Using Parallel Computing

    Science.gov (United States)

    Tarboton, D. G.; Watson, D. W.; Wallace, R. M.; Schreuders, K.; Tesfa, T. K.

    2009-12-01

    Topography in the form of Digital Elevation Models (DEMs), is widely used to derive information for the modeling of hydrologic processes. Hydrologic terrain analysis augments the information content of digital elevation data by removing spurious pits, deriving a structured flow field, and calculating surfaces of hydrologic information derived from the flow field. The increasing availability of high-resolution terrain datasets for large areas poses a challenge for existing algorithms that process terrain data to extract this hydrologic information. This paper will describe parallel algorithms that have been developed to enhance hydrologic terrain pre-processing so that larger datasets can be more efficiently computed. Message Passing Interface (MPI) parallel implementations have been developed for pit removal, flow direction, and generalized flow accumulation methods within the Terrain Analysis Using Digital Elevation Models (TauDEM) package. The parallel algorithm works by decomposing the domain into striped or tiled data partitions where each tile is processed by a separate processor. This method also reduces the memory requirements of each processor so that larger size grids can be processed. The parallel pit removal algorithm is adapted from the method of Planchon and Darboux that starts from a high elevation then progressively scans the grid, lowering each grid cell to the maximum of the original elevation or the lowest neighbor. The MPI implementation reconciles elevations along process domain edges after each scan. Generalized flow accumulation extends flow accumulation approaches commonly available in GIS through the integration of multiple inputs and a broad class of algebraic rules into the calculation of flow related quantities. It is based on establishing a flow field through DEM grid cells, that is then used to evaluate any mathematical function that incorporates dependence on values of the quantity being evaluated at upslope (or downslope) grid cells

  5. TERRAIN Submission for CHICKASAW, IA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  6. TERRAIN, HART COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  7. TERRAIN, LEVY COUNTY, FL, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  8. TERRAIN, CHOCTAW COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. TERRAIN, CULLMAN COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. TERRAIN, NELSON COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  11. TERRAIN, MENIFEE COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  12. TERRAIN, GREENE COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. TERRAIN, CLARKE COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. TERRAIN, ESTILL COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  15. TERRAIN, ELMORE COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. TERRAIN, MARSHALL COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  17. TERRAIN, ANNE ARUNDEL COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. TERRAIN, LIMESTONE COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  19. TERRAIN, HALE COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  20. TERRAIN, RUSSELL COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. TERRAIN, OHIO COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. TERRAIN, JEFFERSON COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  3. TERRAIN, MCCREARY COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  4. TERRAIN, FAYETTE COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  5. TERRAIN, WAYNE COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  6. TERRAIN, MADISON COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  7. TERRAIN, MONROE COUNTY, Michigan USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  8. TERRAIN, CAMPBELL COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. TERRAIN, Metcalfe COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. TERRAIN, CRITTENDEN COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  11. TERRAIN, Cedar COUNTY, Missouri USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  12. TERRAIN, TRIGG COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. TERRAIN, Fleming COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. Self-Supervised Learning of Terrain Traversability from Proprioceptive Sensors

    Science.gov (United States)

    Bajracharya, Max; Howard, Andrew B.; Matthies, Larry H.

    2009-01-01

    Robust and reliable autonomous navigation in unstructured, off-road terrain is a critical element in making unmanned ground vehicles a reality. Existing approaches tend to rely on evaluating the traversability of terrain based on fixed parameters obtained via testing in specific environments. This results in a system that handles the terrain well that it trained in, but is unable to process terrain outside its test parameters. An adaptive system does not take the place of training, but supplements it. Whereas training imprints certain environments, an adaptive system would imprint terrain elements and the interactions amongst them, and allow the vehicle to build a map of local elements using proprioceptive sensors. Such sensors can include velocity, wheel slippage, bumper hits, and accelerometers. Data obtained by the sensors can be compared to observations from ranging sensors such as cameras and LADAR (laser detection and ranging) in order to adapt to any kind of terrain. In this way, it could sample its surroundings not only to create a map of clear space, but also of what kind of space it is and its composition. By having a set of building blocks consisting of terrain features, a vehicle can adapt to terrain that it has never seen before, and thus be robust to a changing environment. New observations could be added to its library, enabling it to infer terrain types that it wasn't trained on. This would be very useful in alien environments, where many of the physical features are known, but some are not. For example, a seemingly flat, hard plain could actually be soft sand, and the vehicle would sense the sand and avoid it automatically.

  15. Application of Digital Terrain Model to volcanology

    Directory of Open Access Journals (Sweden)

    V. Achilli

    2006-06-01

    Full Text Available Three-dimensional reconstruction of the ground surface (Digital Terrain Model, DTM, derived by airborne GPS photogrammetric surveys, is a powerful tool for implementing morphological analysis in remote areas. High accurate 3D models, with submeter elevation accuracy, can be obtained by images acquired at photo scales between 1:5000-1:20000. Multitemporal DTMs acquired periodically over volcanic area allow the monitoring of areas interested by crustal deformations and the evaluation of mass balance when large instability phenomena or lava flows have occurred. The work described the results obtained from the analysis of photogrammetric data collected over the Vulcano Island from 1971 to 2001. The data, processed by means of the Digital Photogrammetry Workstation DPW 770, provided DTM with accuracy ranging between few centimeters to few decimeters depending on the geometric image resolution, terrain configuration and quality of photographs.

  16. Evaluation of different digital elevation models for analyzing drainage morphometric parameters in a mountainous terrain: a case study of the Supin-Upper Tons Basin, Indian Himalayas.

    Science.gov (United States)

    Das, Sayantan; Patel, Priyank Pravin; Sengupta, Somasis

    2016-01-01

    With myriad geospatial datasets now available for terrain information extraction and particularly streamline demarcation, there arises questions regarding the scale, accuracy and sensitivity of the initial dataset from which these aspects are derived, as they influence all other parameters computed subsequently. In this study, digital elevation models (DEM) derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER V2), Shuttle Radar Topography Mission (SRTM V4, C-Band, 3 arc-second), Cartosat -1 (CartoDEM 1.0) and topographical maps (R.F. 1:250,000 and 1:50,000), have been used to individually extract and analyze the relief, surface, size, shape and texture properties of a mountainous drainage basin. Nestled inside a mountainous setting, the basin is a semi-elongated one with high relief ratio (>90), steep slopes (25°-30°) and high drainage density (>3.5 km/sq km), as computed from the different DEMs. The basin terrain and stream network is extracted from each DEM, whose morphometric attributes are compared with the surveyed stream networks present in the topographical maps, with resampling of finer DEM datasets to coarser resolutions, to reduce scale-implications during the delineation process. Ground truth verifications for altitudinal accuracy have also been done by a GPS survey. DEMs derived from the 1:50,000 topographical map and ASTER GDEM V2 data are found to be more accurate and consistent in terms of absolute accuracy, than the other generated or available DEM data products, on basis of the morphometric parameters extracted from each. They also exhibit a certain degree of proximity to the surveyed topographical map.

  17. Spectra of Velocity components over Complex Terrain

    DEFF Research Database (Denmark)

    Panofsky, H. A.; Larko, D.; Lipschut, R.

    1982-01-01

    Spectra have been measured over a variety of types of complex terrain: on tops of hills and escarpments, over land downstream of a water surface, and over rolling terrain. Differences between spectra over many types of complex terrain, and over uniform terrain, can be explained by these hypotheses...

  18. Complete Scene Recovery and Terrain Classification in Textured Terrain Meshes

    Directory of Open Access Journals (Sweden)

    Kyhyun Um

    2012-08-01

    Full Text Available Terrain classification allows a mobile robot to create an annotated map of its local environment from the three-dimensional (3D and two-dimensional (2D datasets collected by its array of sensors, including a GPS receiver, gyroscope, video camera, and range sensor. However, parts of objects that are outside the measurement range of the range sensor will not be detected. To overcome this problem, this paper describes an edge estimation method for complete scene recovery and complete terrain reconstruction. Here, the Gibbs-Markov random field is used to segment the ground from 2D videos and 3D point clouds. Further, a masking method is proposed to classify buildings and trees in a terrain mesh.

  19. Processing Terrain Point Cloud Data

    KAUST Repository

    DeVore, Ronald

    2013-01-10

    Terrain point cloud data are typically acquired through some form of Light Detection And Ranging sensing. They form a rich resource that is important in a variety of applications including navigation, line of sight, and terrain visualization. Processing terrain data has not received the attention of other forms of surface reconstruction or of image processing. The goal of terrain data processing is to convert the point cloud into a succinct representation system that is amenable to the various application demands. The present paper presents a platform for terrain processing built on the following principles: (i) measuring distortion in the Hausdorff metric, which we argue is a good match for the application demands, (ii) a multiscale representation based on tree approximation using local polynomial fitting. The basic elements held in the nodes of the tree can be efficiently encoded, transmitted, visualized, and utilized for the various target applications. Several challenges emerge because of the variable resolution of the data, missing data, occlusions, and noise. Techniques for identifying and handling these challenges are developed. © 2013 Society for Industrial and Applied Mathematics.

  20. Complex Terrain and Wind Lidars

    DEFF Research Database (Denmark)

    Bingöl, Ferhat

    This thesis includes the results of a PhD study about complex terrain and wind lidars. The study mostly focuses on hilly and forested areas. Lidars have been used in combination with cups, sonics and vanes, to reach the desired vertical measurement heights. Several experiments are performed...... in complex terrain sites and the measurements are compared with two different flow models; a linearised flow model LINCOM and specialised forest model SCADIS. In respect to the lidar performance in complex terrain, the results showed that horizontal wind speed errors measured by a conically scanning lidar...... models and the comparison of the measurement data with the flow model outputs showed that the mean wind speed calculated by LINCOM model was only reliable between 1 and 2 tree height (h) above canopy. The SCADIS model reported better correlation with the measurements in forest up to ∼6h. At the forest...

  1. Iapetus Bright and Dark Terrains

    Science.gov (United States)

    1990-01-01

    Saturn's outermost large moon, Iapetus, has a bright, heavily cratered icy terrain and a dark terrain, as shown in this Voyager 2 image taken on August 22, 1981. Amazingly, the dark material covers precisely the side of Iapetus that leads in the direction of orbital motion around Saturn (except for the poles), whereas the bright material occurs on the trailing hemisphere and at the poles. The bright terrain is made of dirty ice, and the dark terrain is surfaced by carbonaceous molecules, according to measurements made with Earth-based telescopes. Iapetus' dark hemisphere has been likened to tar or asphalt and is so dark that no details within this terrain were visible to Voyager 2. The bright icy hemisphere, likened to dirty snow, shows many large impact craters. The closest approach by Voyager 2 to Iapetus was a relatively distant 600,000 miles, so that our best images, such as this, have a resolution of about 12 miles. The dark material is made of organic substances, probably including poisonous cyano compounds such as frozen hydrogen cyanide polymers. Though we know a little about the dark terrain's chemical nature, we do not understand its origin. Two theories have been developed, but neither is fully satisfactory--(1) the dark material may be organic dust knocked off the small neighboring satellite Phoebe and 'painted' onto the leading side of Iapetus as the dust spirals toward Saturn and Iapetus hurtles through the tenuous dust cloud, or (2) the dark material may be made of icy-cold carbonaceous 'cryovolcanic' lavas that were erupted from Iapetus' interior and then blackened by solar radiation, charged particles, and cosmic rays. A determination of the actual cause, as well as discovery of any other geologic features smaller than 12 miles across, awaits the Cassini Saturn orbiter to arrive in 2004.

  2. Complex terrain and wind lidars

    Energy Technology Data Exchange (ETDEWEB)

    Bingoel, F.

    2009-08-15

    This thesis includes the results of a PhD study about complex terrain and wind lidars. The study mostly focuses on hilly and forested areas. Lidars have been used in combination with cups, sonics and vanes, to reach the desired vertical measurement heights. Several experiments are performed in complex terrain sites and the measurements are compared with two different flow models; a linearised flow model LINCOM and specialised forest model SCADIS. In respect to the lidar performance in complex terrain, the results showed that horizontal wind speed errors measured by a conically scanning lidar can be of the order of 3-4% in moderately-complex terrain and up to 10% in complex terrain. The findings were based on experiments involving collocated lidars and meteorological masts, together with flow calculations over the same terrains. The lidar performance was also simulated with the commercial software WAsP Engineering 2.0 and was well predicted except for some sectors where the terrain is particularly steep. Subsequently, two experiments were performed in forested areas; where the measurements are recorded at a location deep-in forest and at the forest edge. Both sites were modelled with flow models and the comparison of the measurement data with the flow model outputs showed that the mean wind speed calculated by LINCOM model was only reliable between 1 and 2 tree height (h) above canopy. The SCADIS model reported better correlation with the measurements in forest up to approx6h. At the forest edge, LINCOM model was used by allocating a slope half-in half out of the forest based on the suggestions of previous studies. The optimum slope angle was reported as 17 deg.. Thus, a suggestion was made to use WAsP Engineering 2.0 for forest edge modelling with known limitations and the applied method. The SCADIS model worked better than the LINCOM model at the forest edge but the model reported closer results to the measurements at upwind than the downwind and this should be

  3. Evaluation of a Sub-Grid Topographic Drag Parameterizations for Modeling Surface Wind Speed During Storms Over Complex Terrain in the Northeast U.S.

    Science.gov (United States)

    Frediani, M. E.; Hacker, J.; Anagnostou, E. N.; Hopson, T. M.

    2015-12-01

    This study aims at improving regional simulation of 10-meter wind speed by verifying PBL schemes for storms at different scales, including convective storms, blizzards, tropical storms and nor'easters over complex terrain in the northeast U.S. We verify a recently proposed sub-grid topographic drag scheme in stormy conditions and compare it with two PBL schemes (Mellor-Yamada and Yonsei University) from WRF-ARW over a region in the Northeast U.S. The scheme was designed to adjust the surface drag over regions with high subgrid-scale topographic variability. The schemes are compared using spatial, temporal, and pattern criteria against surface observations. The spatial and temporal criteria are defined by season, diurnal cycle, and topography; the pattern, is based on clusters derived using clustering analysis. Results show that the drag scheme reduces the positive bias of low wind speeds, but over-corrects the high wind speeds producing a magnitude-increasing negative bias with increasing speed. Both other schemes underestimate the most frequent low-speed mode and overestimate the high-speeds. Error characteristics of all schemes respond to seasonal and diurnal cycle changes. The Topo-wind experiment shows the best agreement with the observation quantiles in summer and fall, the best representation of the diurnal cycle in these seasons, and reduces the bias of all surface stations near the coast. In more stable conditions the Topo-wind scheme shows a larger negative bias. The cluster analysis reveals a correlation between bias and mean speed from the Mellor-Yamada and Yonsei University schemes that is not present when the drag scheme is used. When the drag scheme is used the bias correlates with wind direction; the bias increases when the meridional wind component is negative. This pattern corresponds to trajectories with more land interaction with the highest biases found in northwest circulation clusters.

  4. Digital terrain tapes: user guide

    Science.gov (United States)

    ,

    1980-01-01

    DMATC's digital terrain tapes are a by-product of the agency's efforts to streamline the production of raised-relief maps. In the early 1960's DMATC developed the Digital Graphics Recorder (DGR) system that introduced new digitizing techniques and processing methods into the field of three-dimensional mapping. The DGR system consisted of an automatic digitizing table and a computer system that recorded a grid of terrain elevations from traces of the contour lines on standard topographic maps. A sequence of computer accuracy checks was performed and then the elevations of grid points not intersected by contour lines were interpolated. The DGR system produced computer magnetic tapes which controlled the carving of plaster forms used to mold raised-relief maps. It was realized almost immediately that this relatively simple tool for carving plaster molds had enormous potential for storing, manipulating, and selectively displaying (either graphically or numerically) a vast number of terrain elevations. As the demand for the digital terrain tapes increased, DMATC began developing increasingly advanced digitizing systems and now operates the Digital Topographic Data Collection System (DTDCS). With DTDCS, two types of data elevations as contour lines and points, and stream and ridge lines are sorted, matched, and resorted to obtain a grid of elevation values for every 0.01 inch on each map (approximately 200 feet on the ground). Undefined points on the grid are found by either linear or or planar interpolation.

  5. Urban Terrain Analysis Training Aids

    Science.gov (United States)

    1981-09-01

    Continue on reverse aide If necessary and iden t i f y by b lock number) MOBA a Combat-In-Cities Training Aids for Urban Combat Urban Terrain ZQ...Urban Areas Working Group of the Military Operations Research Society; the joint DARCOM-TRADOC (U.S. Army) MOUT conferences; and a special MOBA

  6. Quantifying the added value of convection-permitting climate simulations in complex terrain: a systematic evaluation of WRF over the Himalayas

    Directory of Open Access Journals (Sweden)

    R. Karki

    2017-07-01

    Full Text Available Mesoscale dynamical refinements of global climate models or atmospheric reanalysis have shown their potential to resolve intricate atmospheric processes, their land surface interactions, and subsequently, realistic distribution of climatic fields in complex terrains. Given that such potential is yet to be explored within the central Himalayan region of Nepal, we investigate the skill of the Weather Research and Forecasting (WRF model with different spatial resolutions in reproducing the spatial, seasonal, and diurnal characteristics of the near-surface air temperature and precipitation as well as the spatial shifts in the diurnal monsoonal precipitation peak over the Khumbu (Everest, Rolwaling, and adjacent southern areas. Therefore, the ERA-Interim (0.75° reanalysis has been dynamically refined to 25, 5, and 1 km (D1, D2, and D3 for one complete hydrological year (October 2014–September 2015, using the one-way nested WRF model run with mild nudging and parameterized convection for the outer but explicitly resolved convection for the inner domains. Our results suggest that D3 realistically reproduces the monsoonal precipitation, as compared to its underestimation by D1 but overestimation by D2. All three resolutions, however, overestimate precipitation from the westerly disturbances, owing to simulating anomalously higher intensity of few intermittent events. Temperatures are generally reproduced well by all resolutions; however, winter and pre-monsoon seasons feature a high cold bias for high elevations while lower elevations show a simultaneous warm bias. Unlike higher resolutions, D1 fails to realistically reproduce the regional-scale nocturnal monsoonal peak precipitation observed in the Himalayan foothills and its diurnal shift towards high elevations, whereas D2 resolves these characteristics but exhibits a limited skill in reproducing such a peak on the river valley scale due to the limited representation of the narrow valleys at 5

  7. Quantifying the added value of convection-permitting climate simulations in complex terrain: a systematic evaluation of WRF over the Himalayas

    Science.gov (United States)

    Karki, Ramchandra; Hasson, Shabeh ul; Gerlitz, Lars; Schickhoff, Udo; Scholten, Thomas; Böhner, Jürgen

    2017-07-01

    Mesoscale dynamical refinements of global climate models or atmospheric reanalysis have shown their potential to resolve intricate atmospheric processes, their land surface interactions, and subsequently, realistic distribution of climatic fields in complex terrains. Given that such potential is yet to be explored within the central Himalayan region of Nepal, we investigate the skill of the Weather Research and Forecasting (WRF) model with different spatial resolutions in reproducing the spatial, seasonal, and diurnal characteristics of the near-surface air temperature and precipitation as well as the spatial shifts in the diurnal monsoonal precipitation peak over the Khumbu (Everest), Rolwaling, and adjacent southern areas. Therefore, the ERA-Interim (0.75°) reanalysis has been dynamically refined to 25, 5, and 1 km (D1, D2, and D3) for one complete hydrological year (October 2014-September 2015), using the one-way nested WRF model run with mild nudging and parameterized convection for the outer but explicitly resolved convection for the inner domains. Our results suggest that D3 realistically reproduces the monsoonal precipitation, as compared to its underestimation by D1 but overestimation by D2. All three resolutions, however, overestimate precipitation from the westerly disturbances, owing to simulating anomalously higher intensity of few intermittent events. Temperatures are generally reproduced well by all resolutions; however, winter and pre-monsoon seasons feature a high cold bias for high elevations while lower elevations show a simultaneous warm bias. Unlike higher resolutions, D1 fails to realistically reproduce the regional-scale nocturnal monsoonal peak precipitation observed in the Himalayan foothills and its diurnal shift towards high elevations, whereas D2 resolves these characteristics but exhibits a limited skill in reproducing such a peak on the river valley scale due to the limited representation of the narrow valleys at 5 km resolution

  8. An automated system for terrain database construction

    Science.gov (United States)

    Johnson, L. F.; Fretz, R. K.; Logan, T. L.; Bryant, N. A.

    1987-01-01

    An automated Terrain Database Preparation System (TDPS) for the construction and editing of terrain databases used in computerized wargaming simulation exercises has been developed. The TDPS system operates under the TAE executive, and it integrates VICAR/IBIS image processing and Geographic Information System software with CAD/CAM data capture and editing capabilities. The terrain database includes such features as roads, rivers, vegetation, and terrain roughness.

  9. Atmospheric studies in complex terrain: a planning guide for future studies

    Energy Technology Data Exchange (ETDEWEB)

    Orgill, M.M.

    1981-02-01

    The objective of this study is to assist the US Department of Energy in Conducting its atmospheric studies in complex terrain (ASCOT0 by defining various complex terrain research systems and relating these options to specific landforms sites. This includes: (1) reviewing past meteorological and diffusion research on complex terrain; (2) relating specific terrain-induced airflow phenomena to specific landforms and time and space scales; (3) evaluating the technical difficulty of modeling and measuring terrain-induced airflow phenomena; and (4) avolving severdal research options and proposing candidate sites for continuing and expanding field and modeling work. To evolve research options using variable candidate sites, four areas were considered: site selection, terrain uniqueness and quantification, definition of research problems and research plans. 36 references, 111 figures, 20 tables.

  10. Handling Massive and Dynamic Terrain Data

    DEFF Research Database (Denmark)

    Revsbæk, Morten

    analyzing flood risk and visibility, to producing nautical charts. Many algorithms and much commercial software have been developed to help analyze terrain models. However, significant algorithmic challenges arise from the increasing detail (and therefore size) of modern terrain models. Furthermore, terrain...

  11. Terrain Analyst Synthesizer Station.

    Science.gov (United States)

    1980-06-01

    The TASS was de- livered to ETL on 24 September 1979 for test and evaluation. Originally, TASS was called the Map Compositor and Display Projector (MCDP...ARMY ENGINEER TOPOGRAPHIC LABORATORIES PURCHASE DESCRIPTION 21 April 1978 MAP COMPOSITOR AND DISPLAY PROJECTOR (MCDP) 1. Scope. This Purchase...Description defines the requirements for the design and fabrication of a compositor -projector system to be used in com- plexing factor overlays and other

  12. IEA-Task 31 WAKEBENCH: Towards a protocol for wind farm flow model evaluation. Part 1: Flow-over-terrain models

    DEFF Research Database (Denmark)

    Rodrigo, Javier Sanz; Gancarski, Pawel; Arroyo, Roberto Chavez

    2014-01-01

    The IEA Task 31 Wakebench is setting up a framework for the evaluation of wind farm flow models operating at microscale level. The framework consists on a model evaluation protocol integrated on a web-based portal for model benchmarking (www.windbench.net). This paper provides an overview of the ...

  13. Prediction models in complex terrain

    DEFF Research Database (Denmark)

    Marti, I.; Nielsen, Torben Skov; Madsen, Henrik

    2001-01-01

    The objective of the work is to investigatethe performance of HIRLAM in complex terrain when used as input to energy production forecasting models, and to develop a statistical model to adapt HIRLAM prediction to the wind farm. The features of the terrain, specially the topography, influence...... are calculated using on-line measurements of power production as well as HIRLAM predictions as input thus taking advantage of the auto-correlation, which is present in the power production for shorter pediction horizons. Statistical models are used to discribe the relationship between observed energy production...... the performance of HIRLAM in particular with respect to wind predictions. To estimate the performance of the model two spatial resolutions (0,5 Deg. and 0.2 Deg.) and different sets of HIRLAM variables were used to predict wind speed and energy production. The predictions of energy production for the wind farms...

  14. Quantification of rock slope terrain properties

    Science.gov (United States)

    Volkwein, Axel; Gerber, Werner

    2017-04-01

    Rockfall trajectory simulation codes need information on the terrain properties to formulate appropriate rebound models. Usually, the manuals of rockfall simulation codes give sketches or photographs of terrain samples [1,2]. Based on these the user can select suitable terrains for the simulation area. We now would like to start a discussion whether it is possible to numerically quantify the terrain properties which would make the ground assignment more objective. Different ground properties play a role for the interaction between a falling rock and the ground: • Elastic deformation • plastic deformation • Energy absorption • friction • hardness • roughness • surface vs. underground • etc. The question is now whether it is possible to quantify above parameters and to finally provide tables that contain appropriate simulation parameters. In a first attempt we suggest different methods or parameters that might be evaluated in situ: • Small scale drop tests • Light weight deflectometer (LWD) • Particle sizes • Sliding angle • Particle distribution • Soil cover • Water content Of course, above measurements will never perfectly fit to different mountain slopes. However, if a number of measurements has been made their spreading will give an idea on the natural variability of the ground properties. As an example, the following table gives an idea on how the ME and Evd values vary for different soils. Table 1: LWD measurements on different soil types [3] Ground type Soil layer Soil humidityEvd (median)σ (median)Evd (average) Humus-carb. < 10cm dry 17.4 6.8 15.6 Regosol 10 - 30cm dry 8.6 3.9 9.4 Brownish 30 - 50cm dry 12.1 3.2 11.7 Calcaric 30 - 50cm dry 7.5 3.3 7.0 Acid brownish70 - 100cmdry 7.8 2.1 7.7 Fahlgley 10 - 30cm dry 9.2 4.0 7.7 References [1] Bartelt P et al (2016) RAMMS::rockfall user manual v1.6. SLF, Davos. [2] Dorren L.K.A., 2015. Rockyfor3D (v5.2) revealed - Transparent description of the complete 3D rockfall model. ecoris

  15. Robotic concepts for operation in barren terrain. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Dowling, K. [Carnegie-Mellon Univ., Pittsburgh, PA (United States)

    1993-01-01

    We have performed a series of studies and configurations for robots that are capable of operating in rough barren terrains. The environments we are targeting are like those of the moon or other planets in the roughness and starkness of the terrains, the loose and hard materials that range from sandy slopes to boulder fields, and the extremes of temperature that are encountered in such places. We present a mission scenario, requirements and then present and evaluate a mechanism design. Additional subsystem issues of power, communication, sensing, and computing are all addressed with respect to these requirements.

  16. Selection of key terrain attributes for SOC model

    DEFF Research Database (Denmark)

    Greve, Mogens Humlekrog; Adhikari, Kabindra; Chellasamy, Menaka

    of predictors in Digital soil mapping of SOC. But there are no rules only few empirical guidelines on which digital terrain attributes to use. The aim of this paper was to select and the evaluate 21 digital terrain attributes and use the best for mapping. A typical 7500 km2 region located in Denmark...... was selected, total 2,514,820 data mining models were constructed by 71 differences grid from 12m to 2304m and 22 attributes, 21 attributes derived by DTM and the original elevation. Relative importance and usage of each attributes in every model were calculated. Comprehensive impact rates of each attribute...... which was processed by weighting, grouping, summation and normalization was taken as the important indicator in SOC model. The results showed that there use differences in the SOC model using different terrain attributes. Relative Slope Position(RSP), Channel Altitude(Chnl_alti),and Standard High...

  17. Evaluating horizontal positional accuracy of low-cost UAV orthomosaics over forest terrain using ground control points extracted from different sources

    Science.gov (United States)

    Patias, Petros; Giagkas, Fotis; Georgiadis, Charalampos; Mallinis, Giorgos; Kaimaris, Dimitris; Tsioukas, Vassileios

    2017-09-01

    Within the field of forestry, forest road mapping and inventory plays an important role in management activities related to wood harvesting industry, sentiment and water run-off modelling, biodiversity distribution and ecological connectivity, recreation activities, future planning of forest road networks and wildfire protection and fire-fighting. Especially in countries of the Mediterranean Rim, knowledge at regional and national scales regarding the distribution and the characteristics of rural and forest road network is essential in order to ensure an effective emergency management and rapid response of the fire-fighting mechanism. Yet, the absence of accurate and updated geodatabases and the drawbacks related to the use of traditional cartographic methods arising from the forest environment settings, and the cost and efforts needed, as thousands of meters need to be surveyed per site, trigger the need for new data sources and innovative mapping approaches. Monitoring the condition of unpaved forest roads with unmanned aerial vehicle technology is an attractive option for substituting objective, laboursome surveys. Although photogrammetric processing of UAV imagery can achieve accuracy of 1-2 centimeters and dense point clouds, the process is commonly based on the establishment of control points. In the case of forest road networks, which are linear features, there is a need for a great number of control points. Our aim is to evaluate low-cost UAV orthoimages generated over forest areas with GCP's captured from existing national scale aerial orthoimagery, satellite imagery available through a web mapping service (WMS), field surveys using Mobile Mapping System and GNSS receiver. We also explored the direct georeferencing potential through the GNSS onboard the low cost UAV. The results suggest that the GNSS approach proved to most accurate, while the positional accuracy derived using the WMS and the aerial orthoimagery datasets deemed satisfactory for the

  18. A parameter optimization tool for evaluating the physical consistency of the plot-scale water budget of the integrated eco-hydrological model GEOtop in complex terrain

    Science.gov (United States)

    Bertoldi, Giacomo; Cordano, Emanuele; Brenner, Johannes; Senoner, Samuel; Della Chiesa, Stefano; Niedrist, Georg

    2017-04-01

    In mountain regions, the plot- and catchment-scale water and energy budgets are controlled by a complex interplay of different abiotic (i.e. topography, geology, climate) and biotic (i.e. vegetation, land management) controlling factors. When integrated, physically-based eco-hydrological models are used in mountain areas, there are a large number of parameters, topographic and boundary conditions that need to be chosen. However, data on soil and land-cover properties are relatively scarce and do not reflect the strong variability at the local scale. For this reason, tools for uncertainty quantification and optimal parameters identification are essential not only to improve model performances, but also to identify most relevant parameters to be measured in the field and to evaluate the impact of different assumptions for topographic and boundary conditions (surface, lateral and subsurface water and energy fluxes), which are usually unknown. In this contribution, we present the results of a sensitivity analysis exercise for a set of 20 experimental stations located in the Italian Alps, representative of different conditions in terms of topography (elevation, slope, aspect), land use (pastures, meadows, and apple orchards), soil type and groundwater influence. Besides micrometeorological parameters, each station provides soil water content at different depths, and in three stations (one for each land cover) eddy covariance fluxes. The aims of this work are: (I) To present an approach for improving calibration of plot-scale soil moisture and evapotranspiration (ET). (II) To identify the most sensitive parameters and relevant factors controlling temporal and spatial differences among sites. (III) Identify possible model structural deficiencies or uncertainties in boundary conditions. Simulations have been performed with the GEOtop 2.0 model, which is a physically-based, fully distributed integrated eco-hydrological model that has been specifically designed for mountain

  19. A Wetness Index Using Terrain-Corrected Surface Temperature and Normalized Difference Vegetation Index Derived from Standard MODIS Products: An Evaluation of Its Use in a Humid Forest-Dominated Region of Eastern Canada

    Directory of Open Access Journals (Sweden)

    Roger M. Cox

    2007-10-01

    Full Text Available In this paper we develop a method to estimate land-surface water content in amostly forest-dominated (humid and topographically-varied region of eastern Canada. Theapproach is centered on a temperature-vegetation wetness index (TVWI that uses standard 8-day MODIS-based image composites of land surface temperature (TS and surface reflectanceas primary input. In an attempt to improve estimates of TVWI in high elevation areas, terrain-induced variations in TS are removed by applying grid, digital elevation model-basedcalculations of vertical atmospheric pressure to calculations of surface potential temperature(θS. Here, θS corrects TS to the temperature value to what it would be at mean sea level (i.e.,~101.3 kPa in a neutral atmosphere. The vegetation component of the TVWI uses 8-daycomposites of surface reflectance in the calculation of normalized difference vegetation index(NDVI values. TVWI and corresponding wet and dry edges are based on an interpretation ofscatterplots generated by plotting θS as a function of NDVI. A comparison of spatially-averaged field measurements of volumetric soil water content (VSWC and TVWI for the 2003-2005 period revealed that variation with time to both was similar in magnitudes. Growing season, point mean measurements of VSWC and TVWI were 31.0% and 28.8% for 2003, 28.6% and 29.4% for 2004, and 40.0% and 38.4% for 2005, respectively. An evaluation of the long-term spatial distribution of land-surface wetness generated with the new θS-NDVI function and a process-based model of soil water content showed a strong relationship (i.e., r2 = 95.7%.

  20. Rough terrain motion planning for actively reconfigurable mobile robots

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, Michael

    2015-02-05

    In the aftermath of the Tohoku earthquake and the nuclear meltdown at the power plant of Fukushima Daiichi in 2011, reconfigurable robots like the iRobot Packbot were deployed. Instead of humans, the robots were used to investigate contaminated areas. Other incidents are the two major earthquakes in Northern Italy in May 2012. Besides many casualties, a large number of historical buildings was severely damaged. Due to the imminent danger of collapse, it was too dangerous for rescue personnel to enter many of the buildings. Therefore, the sites were inspected by reconfigurable robots, which are able to traverse the rubble and debris of the partially destroyed buildings. This thesis develops a navigation system enabling wheeled and tracked robots to safely traverse rough terrain and challenging structures. It consists of a planning mechanism and a controller. The focus of this thesis, however, is on the contribution to motion planning. The planning scheme employs a hierarchical approach to motion planning for actively reconfigurable robots in rough environments. Using a map of the environment the algorithm estimates the traversability under the consideration of uncertainties. Based on this analysis, an initial path search determines an approximate solution with respect to the robot's operating limits.Subsequently, a detailed planning step refines the initial path where it is required. The refinement step considers the robot's actuators and stability in addition to the quantities of the first search. Determining the robot-terrain interaction is very important in rough terrain. This thesis presents two path refinement approaches: a deterministic and a randomized approach. The experimental evaluation investigates the separate components of the planning scheme, the robot-terrain interaction for instance.In simulation as well as in real world experiments the evaluation demonstrates the necessity of such a planning algorithm in rough terrain and it provides

  1. A GPS inspired Terrain Referenced Navigation algorithm

    NARCIS (Netherlands)

    Vaman, D.

    2014-01-01

    Terrain Referenced Navigation (TRN) refers to a form of localization in which measurements of distances to the terrain surface are matched with a digital elevation map allowing a vehicle to estimate its own position within the map. The main goal of this dissertation is to improve TRN performance

  2. Terrain Classification of Norwegian Slab Avalanche Accidents

    Science.gov (United States)

    Hallandvik, Linda; Aadland, Eivind; Vikene, Odd Lennart

    2016-01-01

    It is difficult to rely on snow conditions, weather, and human factors when making judgments about avalanche risk because these variables are dynamic and complex; terrain, however, is more easily observed and interpreted. Therefore, this study aimed to investigate (1) the type of terrain in which historical fatal snow avalanche accidents in Norway…

  3. Computational snow avalanche simulation in forested terrain

    Science.gov (United States)

    Teich, M.; Fischer, J.-T.; Feistl, T.; Bebi, P.; Christen, M.; Grêt-Regamey, A.

    2014-08-01

    Two-dimensional avalanche simulation software operating in three-dimensional terrain is widely used for hazard zoning and engineering to predict runout distances and impact pressures of snow avalanche events. Mountain forests are an effective biological protection measure against avalanches; however, the protective capacity of forests to decelerate or even to stop avalanches that start within forested areas or directly above the treeline is seldom considered in this context. In particular, runout distances of small- to medium-scale avalanches are strongly influenced by the structural conditions of forests in the avalanche path. We present an evaluation and operationalization of a novel detrainment function implemented in the avalanche simulation software RAMMS for avalanche simulation in forested terrain. The new approach accounts for the effect of forests in the avalanche path by detraining mass, which leads to a deceleration and runout shortening of avalanches. The relationship is parameterized by the detrainment coefficient K [kg m-1 s-2] accounting for differing forest characteristics. We varied K when simulating 40 well-documented small- to medium-scale avalanches, which were released in and ran through forests of the Swiss Alps. Analyzing and comparing observed and simulated runout distances statistically revealed values for K suitable to simulate the combined influence of four forest characteristics on avalanche runout: forest type, crown closure, vertical structure and surface cover, for example, values for K were higher for dense spruce and mixed spruce-beech forests compared to open larch forests at the upper treeline. Considering forest structural conditions within avalanche simulations will improve current applications for avalanche simulation tools in mountain forest and natural hazard management.

  4. Predicting Potential Evaporation in Topographically Complex Terrain

    Science.gov (United States)

    Koohafkan, M.; Thompson, S. E.; Hamilton, M. P.

    2012-12-01

    Predicting and understanding the water cycle in topographically complex terrain poses challenges for upscaling point-scale measurements of water and energy balance and for downscaling observations made from remote sensing or predictions made via global circulation models. This study evaluates hydrologic and climate data drawn from a spatially-distributed wireless sensor network at the Blue Oak Ranch Reserve near San Jose, California to investigate the influence of topographic variation, landscape position, and local ecology (vegetation) on one core component of the water balance: potential evaporation. High-resolution observations of solar radiation, ambient temperature, wind speed, and relative humidity are combined with canopy maps generated from LiDAR flyovers to develop spatially-distributed predictions of potential evaporation. These data are compared to estimates of EP based on inverse modeling of surface soil moisture data. Preliminary results suggest that the spatial structure of microclimate at Blue Oak Ranch Reserve is dominated by variations around the elevation gradient, with strong nocturnal inversions hypothesized to reflect the influence of the coastal marine layer. Estimates of EP based on the Penman-Monteith equation suggest that EP could vary by up to a factor of 5 across the site, with differences in vapor pressure deficit and canopy height largely responsible for this variability. The results suggest that a) large differences in the timing and magnitude of water stress could arise in topographically complex terrain due to localized differences in energy balance, and b) both localized and regional effects need to be accounted for when downscaling climate data over topographically complex sites. 2) Color map showing preliminary estimates of annual EP incorporating canopy information (spatially-distributed values of aerodynamic resistance and LAI) drawn from LiDAR imagery. The effect of the resistance on the dynamics is striking in its ability to

  5. Remote sensing of Earth terrain

    Science.gov (United States)

    Kong, J. A.

    1992-01-01

    Research findings are summarized for projects dealing with the following: application of theoretical models to active and passive remote sensing of saline ice; radiative transfer theory for polarimetric remote sensing of pine forest; scattering of electromagnetic waves from a dense medium consisting of correlated Mie scatterers with size distribution and applications to dry snow; variance of phase fluctuations of waves propagating through a random medium; theoretical modeling for passive microwave remote sensing of earth terrain; polarimetric signatures of a canopy of dielectric cylinders based on first and second order vector radiative transfer theory; branching model for vegetation; polarimetric passive remote sensing of periodic surfaces; composite volume and surface scattering model; and radar image classification.

  6. Hydrographic Basins Analysis Using Digital Terrain Modelling

    Science.gov (United States)

    Mihaela, Pişleagă; -Minda Codruţa, Bădăluţă; Gabriel, Eleş; Daniela, Popescu

    2017-10-01

    The paper, emphasis the link between digital terrain modelling and studies of hydrographic basins, concerning the hydrological processes analysis. Given the evolution of computing techniques but also of the software digital terrain modelling made its presence felt increasingly, and established itself as a basic concept in many areas, due to many advantages. At present, most digital terrain modelling is derived from three alternative sources such as ground surveys, photogrammetric data capture or from digitized cartographic sources. A wide range of features may be extracted from digital terrain models, such as surface, specific points and landmarks, linear features but also areal futures like drainage basins, hills or hydrological basins. The paper highlights how the use appropriate software for the preparation of a digital terrain model, a model which is subsequently used to study hydrographic basins according to various geomorphological parameters. As a final goal, it shows the link between digital terrain modelling and hydrographic basins study that can be used to optimize the correlation between digital model terrain and hydrological processes in order to obtain results as close to the real field processes.

  7. Terrain identification for RHex-type robots

    Science.gov (United States)

    Ordonez, Camilo; Shill, Jacob; Johnson, Aaron; Clark, Jonathan; Collins, Emmanuel

    2013-05-01

    Terrain identification is a key enabling ability for generating terrain adaptive behaviors that assist both robot planning and motor control. This paper considers running legged robots from the RHex family) which the military plans to use in the field to assist troops in reconnaissance tasks. Important terrain adaptive behaviors include the selection of gaits) modulation of leg stiffness) and alteration of steering control laws that minimize slippage) maximize speed and/or reduce energy consumption. These terrain adaptive behaviors can be enabled by a terrain identification methodology that combines proprioceptive sensors already available in RHex-type robots. The proposed classification approach is based on the characteristic frequency signatures of data from leg observers) which combine current sensing with a dynamic model of the leg motion. The paper analyzes the classification accuracy obtained using both a single leg and groups of legs (through a voting scheme) on different terrains such as vinyl) asphalt) grass) and pebbles. Additionally) it presents a terrain classifier that works across various gait speeds and in fact almost as good as an overly specialized classifier.

  8. Wind turbine wake measurement in complex terrain

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.; Menke, Robert

    2016-01-01

    SCADA data from a wind farm and high frequency time series measurements obtained with remote scanning systems have been analysed with focus on identification of wind turbine wake properties in complex terrain. The analysis indicates that within the flow regime characterized by medium to large...... downstream distances (more than 5 diameters) from the wake generating turbine, the wake changes according to local atmospheric conditions e.g. vertical wind speed. In very complex terrain the wake effects are often “overruled” by distortion effects due to the terrain complexity or topology....

  9. Avalanche modeling in forested terrain

    Science.gov (United States)

    Teich, M.; Bartelt, P. A.; Bebi, P.; Grêt-Regamey, A.

    2010-12-01

    Mountain forests are a valuable defense against snow avalanches. Currently, however, little quantitative information is available to estimate the effect of forest structure on the motion of avalanches. Avalanche flow is strongly influenced by the condition and composition of vegetation in the avalanche path. This potential decelerating effect has, however, not yet been quantified. We apply the numerical avalanche dynamics program RAMMS to simulate several well documented small avalanche events in forests. The two-dimensional model RAMMS predicts avalanche run-out distances, flow velocities and impact pressures in complex three-dimensional terrain by numerically solving a system of partial differential equations governing avalanche flow. Based on detailed data on forest conditions and avalanche characteristics such as release areas, fracture heights and length collected in forested areas, where avalanches were observed, we modify the input parameters of the RAMMS model to match the observations. We compare the model output with observed run-out distances in order to quantify the decelerating effects of different forest structures. Implementing avalanche forest interactions into numerical avalanche simulations will open new fields of application for avalanche models, e.g. for managing mountain forests and by better accounting for mountain forests as an effective biological protection measure against snow avalanches in natural hazard mapping and landscape planning.

  10. DCS Terrain Submission for Pike County, KY

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

  11. Defending Critical Infrastructure as Cyber Key Terrain

    Science.gov (United States)

    2016-08-01

    AU/ACSC/2016 AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY Defending Critical Infrastructure as Cyber Key Terrain by Derek Molle, Civ, USAF...20 Converged Enterprise Network...23 Logically Isolated Enterprise

  12. Visualization of Features in 3D Terrain

    National Research Council Canada - National Science Library

    Steve Dübel; Heidrun Schumann

    2017-01-01

    In 3D terrain analysis, topographical characteristics, such as mountains or valleys, and geo-spatial data characteristics, such as specific weather conditions or objects of interest, are important features...

  13. DCS Terrain Submission for Charlton Co GA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  14. DCS Terrain for HOUSTON COUNTY, ALABAMA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  15. DCS Terrain Submission for Mohave, AZ

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. TERRAIN, CITY OF DALLAS, DALLAS COUNTY, TEXAS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  17. DCS Terrain Submission for Newton, MS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. DCS Terrain for ELBERT County, GA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  19. TERRAIN Submission for Forest Countywide DFIRM

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  20. DCS Terrain Submission for Ector, TX

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. TERRAIN, CERRO GORDO COUNTY, IOWA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. TERRAIN, UPPER CUMBERLAND WATERSHED, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  3. DCS Terrain Submission for Tyler TX

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  4. Digital Terrain Submittal for Duval County, FL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. DCS Terrain Submission for Albany County NY

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

  6. DCS Terrain Submission for Citrus County FL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

  7. DCS Terrain Submission for Woodward, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  8. DCS Terrain Submission for Merced, CA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. DCS Terrain Submission for Sanders County, Montana

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. DCS Terrain for Middlesex County, NJ

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that were used to create...

  11. Terrain, CEDAR RAPIDS, LINN COUNTY, IA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  12. DCS Terrain Submission for Ulster County NY

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

  13. DCS Terrain Submission for Caddo, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. DCS TERRAIN Submission for STEARNS COUNTY, MN

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  15. DCS Terrain Submission for Lagrange County, IN

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. DCS Terrain Submission for Cass County, MO

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  17. DCS Terrain Submission for Cass County, TX

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. DCS Terrain Submission for Brazos TX

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  19. DCS Terrain Submission for Logan, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  20. DCS Terrain Submission for Carter, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. DCS Terrain Submission for Stephens, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. DCS TERRAIN SUBMISSION FOR MARTIN COUNTY, FL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  3. DCS Terrain Submission for Sioux Falls

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  4. DCS Terrain Submission for Mayes, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. DCS Terrain for Schley County, GA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  6. Automatic terrain modeling using transfinite element analysis

    KAUST Repository

    Collier, Nathan

    2010-05-31

    An automatic procedure for modeling terrain is developed based on L2 projection-based interpolation of discrete terrain data onto transfinite function spaces. The function space is refined automatically by the use of image processing techniques to detect regions of high error and the flexibility of the transfinite interpolation to add degrees of freedom to these areas. Examples are shown of a section of the Palo Duro Canyon in northern Texas.

  7. Terrain classification for a quadruped robot

    OpenAIRE

    Degrave, Jonas; Van Cauwenbergh, Robin; wyffels, Francis; Waegeman, Tim; Schrauwen, Benjamin

    2013-01-01

    Using data retrieved from the Puppy II robot at the University of Zurich (UZH), we show that machine learning techniques with non-linearities and fading memory are effective for terrain classification, both supervised and unsupervised, even with a limited selection of input sensors. The results indicate that most information for terrain classification is found in the combination of tactile sensors and proprioceptive joint angle sensors. The classification error is small enough to have a robot...

  8. The topography of chaos terrain on Europa

    Science.gov (United States)

    Patterson, G.; Prockter, L. M.; Schenk, P.

    2010-12-01

    Chaos terrain and lenticulae are commonly observed surface features unique to the Galilean satellite Europa. Chaos terrain occurs as discrete regions of the satellite’s surface 10s to 100s of km in size that are disrupted into isolated plates surrounded by hummocky matrix material. Lenticulae occur as positive- or negative-relief domes km to 10s of km in diameter that can disrupt the original surface in a manner similar to chaos terrain. Evidence suggests that they each form via an endogenic process involving the interaction of a mobile substrate with the brittle surface and it has been proposed that ice shell thinning or surface yielding coupled with brine production represents the most plausible mechanism for the formation of these features. These similarities in morphology and formation mechanism indicate they may represent a continuum process. We explore whether larger chaos terrain represent the coalescence of smaller lenticulae by examining topography within chaos to determine whether it contains domes on length scales similar to lenticulae. Schenk and Pappalardo (2004) alluded to the presence of several prominent domes within Conamara Chaos and we have previously shown that at least 4 and as many as 9 domes with length scales similar to lenticulae are present within and along the margins of the feature. This was accomplished by using Fourier analysis to decompose the topographic signature of Conamara Chaos and the surrounding terrain into discrete wavelength components. A low-pass filter was then used to strip away shorter wavelength components of the topography associated with the region and determine if longer wavelength features were present within the terrain. Here we present new work identifying the presence, size, and distribution of domes within the boundaries of other chaos terrains across the surface of Europa and discuss implications for chaos formation.

  9. Performance of a wind turbine over a ridged terrain

    Science.gov (United States)

    Santoni, Christian; Ciri, Umberto; Leonardi, Stefano

    2016-11-01

    Performance of wind turbines is affected by their interaction with the topography. Low momentum flow from the terrain may impinge the turbine resulting in fatigue loads that may reduce durability. However, at the same time it may promote the transport of momentum and kinetic energy into the wake improving the power production on the downstream turbines. In order to address how the topography affects the flow, Large Eddy Simulations of a wind turbine located on a wavy surface are performed. The height variation of the topography is described by a sinusoidal wave. Two different amplitudes were considered, 0 . 10 D and 0 . 05 D , where D is the rotor diameter. The wavelength has been kept constant to 3 D . The effect of the relative position of rotor and terrain geometry was assessed by placing the turbine either at the crest or at the trough of the undulated wall. NREL-5MW turbine blades were modeled using the actuator line model whereas the tower, nacelle and topography using the immersed boundary method. A simulation of a wind turbine on a flat terrain was performed as reference case. The performance of the turbine was evaluated in terms of the power production and blade load fluctuations, as well as for the energy entrainment into the wake of the turbine. The numerical simulations were performed on XSEDE TACC under Grant No. CTS070066. This work was supported by the National Science Foundation, Grant Number IIA-1243482 (the WINDINSPIRE project).

  10. Improved Inlet Conditions for Terrain CFD

    DEFF Research Database (Denmark)

    Pedersen, Jesper Grønnegaard

    The atmospheric boundary layer flow over different types of terrain is studied through simulations made with the finite volume CFD code of Ellipsys 2D and 3D. The simulations are compared to measurements made at the Høvsøre test site and over the hill of Askervein.The primary objective...... for describing the flow after a change in the surface roughness. The derivation of these expressions is based on a range of simulations of flows over flat terrain with different types of roughness changes.The derived expressions show good agreement with simulations and could, as intended, be used to define inlet...... conditions for flow simulations over terrain, where an upstream roughness change is thought to have an influence. More thorough experimental verification is however, thought necessary to make the expressions sufficiently reliable. The same goes for the simulations-based conclusions regarding the flow over...

  11. SAR clutter simulation with terrain effects

    Science.gov (United States)

    Greig, David W.; Scott, Iain

    2002-02-01

    A model for the signal returns from terrain features for a Synthetic Aperture Radar is developed. A standard range-azimuth geometry is used to divide the surface area into cells for which clutter returns are generated. This geometry is extended to a spherical Earth to introduce effects due to varying terrain height and slope, and to determine areas of shadow. The calculation of phase variation in the returned pulses at the IQ level required to successfully form a SAR is discussed. The technique is illustrated with an example which demonstrates the effect of look angle on SAR images.

  12. F-16 MMC Strafe in Mountainous Terrain

    Science.gov (United States)

    2016-04-01

    i AU/ACSC/2016 AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY F-16 MMC Strafe in Mountainous Terrain by Jared P. White, Maj, USAF...Modular mission computer ( MMC ) 6.2 OFP introduced auto-ground collision avoidance software into the digital flight control computer (DFLCC). AGCAS

  13. Declarative terrain modeling for military training games

    NARCIS (Netherlands)

    Smelik, R.M.; Tutenel, T.; Kraker, J.K.. de; Bidarra, R.

    2010-01-01

    Military training instructors increasingly often employ computer games to train soldiers in all sorts of skills and tactics. One of the difficulties instructors face when using games as a training tool is the creation of suitable content, including scenarios, entities, and corresponding terrain

  14. Visualization of Large Terrains Made Easy

    Energy Technology Data Exchange (ETDEWEB)

    Lindstrom, P; Pascucci, V

    2001-08-07

    We present an elegant and simple to implement framework for performing out-of-core visualization and view-dependent refinement of large terrain surfaces. Contrary to the recent trend of increasingly elaborate algorithms for large-scale terrain visualization, our algorithms and data structures have been designed with the primary goal of simplicity and efficiency of implementation. Our approach to managing large terrain data also departs from more conventional strategies based on data tiling. Rather than emphasizing how to segment and efficiently bring data in and out of memory, we focus on the manner in which the data is laid out to achieve good memory coherency for data accesses made in a top-down (coarse-to-fine) refinement of the terrain. We present and compare the results of using several different data indexing schemes, and propose a simple to compute index that yields substantial improvements in locality and speed over more commonly used data layouts. Our second contribution is a new and simple, yet easy to generalize method for view-dependent refinement. Similar to several published methods in this area, we use longest edge bisection in a top-down traversal of the mesh hierarchy to produce a continuous surface with subdivision connectivity. In tandem with the refinement, we perform view frustum culling and triangle stripping. These three components are done together in a single pass over the mesh. We show how this framework supports virtually any error metric, while still being highly memory and compute efficient.

  15. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Mølhave, Thomas; Revsbæk, Morten

    2015-01-01

    We study the problem of maintaining the contour tree T of a terrain Sigma, represented as a triangulated xy-monotone surface, as the heights of its vertices vary continuously with time. We characterize the combinatorial changes in T and how they relate to topological changes in Sigma. We present...... an augmented contour tree and a join/split tree....

  16. Scaling Terrain Attributes By Fractal Methods

    Science.gov (United States)

    Terrain attributes derived from grid digital elevation models (DEMs) are commonly used in distributed hydrologic models. However, many attribute estimations are biased by DEM grid cell size. For example, land surface slopes estimated from 30-m DEMs are, on average, less than slopes estimated from ...

  17. Investigation of Terrain Analysis and Classification Methods for Ground Vehicles

    Science.gov (United States)

    2012-08-27

    alignment was verified after every 5 tests, by driving the wheel over a flat, rigid, aluminum plate covered with a thin layer of polyurethane foam in...primarily to their shape , and not to loss of traction between a wheel and the terrain. In contrast, non-geometric hazards are regions of terrain that are...classifier to label the terrain patch. Pairs of terrain class labels and associated visual features are stored in memory . When sufficient data is accumulated

  18. Large-Eddy Simulation of turbine wake in complex terrain

    Science.gov (United States)

    Berg, J.; Troldborg, N.; Sørensen, N. N.; Patton, E. G.; Sullivan, P. P.

    2017-05-01

    We present Large-Eddy Simulation results of a turbine wake in realistic complex terrain with slopes above 0.5. By comparing simulations including and without the wind turbine we can estimate the induction factor, a, and we show how the presence of a strong recirculation zone in the terrain dictates the positioning of the wake. This last finding is in contrast to what would happen in gentle terrain with no substantial increase of turbulent kinetic energy in the terrain induced wakes.

  19. Local-scale stratigraphy of grooved terrain on Ganymede

    Science.gov (United States)

    Murchie, Scott L.; Head, James W.; Helfenstein, Paul; Plescia, Jeffrey B.

    1987-01-01

    The surface of the Jovian satellite, Ganymede, is divided into two main units, dark terrain cut by arcuate and subradial furrows, and light terrain consisting largely of areas with pervasive U-shaped grooves. The grooved terrain may be subdivided on the basis of pervasive morphology of groove domains into four terrain types: (1) elongate bands of parallel grooves (groove lanes); (2) polygonal domains of parallel grooves (grooved polygons); (3) polygonal domains of two orthogonal groove sets (reticulate terrain); and (4) polygons having two to several complexly cross-cutting groove sets (complex grooved terrain). Reticulate terrain is frequently dark and not extensively resurfaced, and grades to a more hummocky terrain type. The other three grooved terrain types have almost universally been resurfaced by light material during their emplacement. The sequence of events during grooved terrain emplacement has been investigated. An attempt is made to integrate observed geologic and tectonic patterns to better constrain the relative ages and styles of emplacement of grooved terrain types. A revised model of grooved terrain emplacement is proposed and is tested using detailed geologic mapping and measurement of crater density.

  20. Large Terrain Continuous Level of Detail 3D Visualization Tool

    Science.gov (United States)

    Myint, Steven; Jain, Abhinandan

    2012-01-01

    This software solved the problem of displaying terrains that are usually too large to be displayed on standard workstations in real time. The software can visualize terrain data sets composed of billions of vertices, and can display these data sets at greater than 30 frames per second. The Large Terrain Continuous Level of Detail 3D Visualization Tool allows large terrains, which can be composed of billions of vertices, to be visualized in real time. It utilizes a continuous level of detail technique called clipmapping to support this. It offloads much of the work involved in breaking up the terrain into levels of details onto the GPU (graphics processing unit) for faster processing.

  1. Planning and design considerations in karst terrain

    Science.gov (United States)

    Fischer, J. A.; Greene, R. W.; Ottoson, R. S.; Graham, T. C.

    1988-10-01

    This article discusses the various steps that the authors feel are necessary to the successful progression of an engineered project sited in karst terrain. The procedures require a multidisciplined approach with liaison and cooperation among the various parties to the project. Initially, the prospective owner must have sufficient understanding of the potential engineering problems to incorporate the engineering geologist into the early stages of any planned acquisition. The first step in an investigation should include a review of the available geologic information, aerial photo interpretation, consultation with the State Geological Survey, and a geologic reconnaissance of the prospective site and surrounding area. A go-no-go decision as to purchase can often been made at an early time. Although, in some instances, more study is needed for a particularly intriguing property. The second stage should consider the various planning alternatives that are feasible based upon the limited available information. At this stage planning/purchase decisions can be made as to purchasing options, value of the property, design constraints, and the possible economic penalties that could be associated with the potential site construction. Various planning and construction alternatives should be considered in this phase of the work. The third stage should include a site investigation program of moderate size, consisting of test pits and/or exploratory borings. The borings should be drilled using water as the drilling fluid, with an experienced crew and qualified technical inspection. The authors find the use of geophysical techniques can be extremely misleading unless used in conjunction with exploratory drilling. Successful evaluations using geophysical procedures occur only under ideal conditions. The geotechnical viability of the plan and preliminary design should be investigated in the fourth phase. Additionally, the physical parameters required for the design of structures

  2. SAR Polarimetric Scattering from Natural Terrains

    Science.gov (United States)

    2017-02-17

    calculate the polarimetric speckle statistics (amplitude and phase difference), followed by a comparison with theoretical distributions . For fully developed...AFRL-AFOSR-JP-TR-2017-0013 SAR Polarimetric Scattering from Natural Terrains Kun-Shan Chen National Central University Final Report 02/17/2017... DISTRIBUTION A: Distribution approved for public release. AF Office Of Scientific Research (AFOSR)/ IOA Arlington, Virginia 22203 Air Force Research

  3. Mean Flow and Turbulence in Complex Terrain

    Science.gov (United States)

    1985-03-01

    empirical power law relationship: aO(T) ( 0 ) x (T0 ) (7) Although the value of x varies with stability, wind speed, and height above the surface, a value...Elevation: 27 ft Terrain: flat river flood plane Vegetation: plowed field with arass at tower base, treeline 100 yds to N Structures: electronic shelter...NNW of tower, radar dish above SW building Comrmn ent: hiih winds indicative of this site, temperature sensor at 6-foot level has possible heating

  4. Recent Military Operations on Urban Terrain

    Science.gov (United States)

    1982-07-01

    SUPPLEMENTARY NOTES Is. KEY WORDS (Continue on reverse. *do If nec.siay and id’ntif• ’ by block neumber) MOBA Egypt Israel C 3 MOUT Jordan Jerusalem Urban...Air Force IDF Israeli Defense Forces m meter mm meters MOBA military operations in built-up areas MOUT military operations on urban terrain TOE table...characteristics of the operation been exploited? 3. What equipment or tactical modifications were made for this MOBA operation? 4. How did Egypt prepare the city

  5. An Effective Terrain Aided Navigation for Low-Cost Autonomous Underwater Vehicles.

    Science.gov (United States)

    Zhou, Ling; Cheng, Xianghong; Zhu, Yixian; Dai, Chenxi; Fu, Jinbo

    2017-03-25

    Terrain-aided navigation is a potentially powerful solution for obtaining submerged position fixes for autonomous underwater vehicles. The application of terrain-aided navigation with high-accuracy inertial navigation systems has demonstrated meter-level navigation accuracy in sea trials. However, available sensors may be limited depending on the type of the mission. Such limitations, especially for low-grade navigation sensors, not only degrade the accuracy of traditional navigation systems, but further impact the ability to successfully employ terrain-aided navigation. To address this problem, a tightly-coupled navigation is presented to successfully estimate the critical sensor errors by incorporating raw sensor data directly into an augmented navigation system. Furthermore, three-dimensional distance errors are calculated, providing measurement updates through the particle filter for absolute and bounded position error. The development of the terrain aided navigation system is elaborated for a vehicle equipped with a non-inertial-grade strapdown inertial navigation system, a 4-beam Doppler Velocity Log range sensor and a sonar altimeter. Using experimental data for navigation performance evaluation in areas with different terrain characteristics, the experiment results further show that the proposed method can be successfully applied to the low-cost AUVs and significantly improves navigation performance.

  6. Mobility versus terrain: a game theoretic approach

    Science.gov (United States)

    Bednarz, David; Muench, Paul

    2016-05-01

    Mobility and terrain are two sides of the same coin. You cannot describe mobility unless you describe the terrain. For example, if my world is trench warfare, the tank may be the ideal vehicle. If my world is urban warfare, clearing buildings and such, the tank may not be an ideal vehicle, perhaps an anthropomorphic robot would be better. We seek a general framework for mobility that captures the relative value of different mobility strategies. Game theory is positively the right way to analyze the interactions of rational players who behave strategically. In this paper, we will describe the interactions between a mobility player, who is trying to make it from point A to point B with one chance to refuel, and a terrain player who is trying to minimize that probability by placing an obstacle somewhere along the path from A to B. In previous work [1], we used Monte Carlo methods to analyze this mobility game, and found optimal strategies for a discretized version of the game. Here we show the relationship of this game to a classic game of timing [2], and use solution methods from that literature to solve for optimal strategies in a continuous version of this mobility game.

  7. Fast integral equation algorithms for the solution of electromagnetic wave propagation over general terrains

    Directory of Open Access Journals (Sweden)

    Ibrahim K. Abu Seif

    2015-01-01

    Full Text Available In this paper a fast numerical algorithm to solve an integral equation model for wave propagation along a perfectly conducting two-dimensional terrain is suggested. It is applied to different actual terrain profiles and the results indicate very good agreement with published work. In addition, the proposed algorithm has achieved considerable saving in processing time. The formulation is extended to solve the propagation over lossy dielectric surfaces. A combined field integral equation (CFIE for wave propagation over dielectric terrain is solved efficiently by utilizing the method of moments with complex basis functions. The numerical results for different cases of dielectric surfaces are compared with the results of perfectly conducting surface evaluated by the IE conventional algorithm.

  8. Pitted terrains on Vesta: Thermophysical analysis

    Science.gov (United States)

    Capria, M.; Tosi, F.; De Sanctis, M.; Turrini, D.; Ammannito, E.; Capaccioni, F.; Fonte, S.; Frigeri, A.; Longobardo, A.; Palomba, E.; Zambon, F.; Schroeder, S.; Denevi, B.; Williams, D.; Scully, J.; Russell, C.; Raymond, C.

    2014-07-01

    Launched in 2007, the Dawn spacecraft, after one year spent orbiting Vesta, is now on its way to Ceres. In the science payload, the Visible and Infrared mapping spectrometer (VIR) is devoted to the study of the mineralogical composition and thermophysical properties of Vesta's surface [1]. Disk-resolved surface temperatures of Vesta have been determined from the infrared spectra measured by VIR [2]. The observed temperatures, together with a thermophysical model, have been used to constrain the thermal properties of a large part of the surface of the asteroid [3]. The average thermal inertia of the surface is quite low, consistent with a widespread presence of a dust layer. While the global thermal inertia is low, the characterization of its surface in terms of regions showing peculiar thermophysical properties gives us the possibility to identify specific areas with different thermal and structural characteristics. These variations can be linked to strong albedo variations that have been observed, or to other physical and structural characteristics of the first few centimeters of the soil. The highest values of thermal inertia have been determined on areas coinciding with locations where pitted terrains have been found [4]. Pitted terrains, first identified on Mars, have been found in association with 4 craters on Vesta: Marcia, Cornelia, Licinia, and Numisia. The Marcia area is characterized by high hydrogen and OH content [5]. By analogy with Mars, the formation of these terrains is thought to be due to the rapid release of volatiles, triggered by heating from an impact event. A question arises on the origin of volatiles: hydrated minerals, or ground, buried ice? In order to discuss the second hypothesis, we have to assume that a comet impact delivers ice that gets buried under a layer of regolith. Successively, another impact on the same area would give origin to the pitted terrain. The buried ice has obviously to survive for the time between the two impacts

  9. Soil and Terrain Database for Malawi (ver. 1.0) (SOTER_Malawi)

    NARCIS (Netherlands)

    Kempen, B.

    2014-01-01

    The Soil and Terrain database for Malawi (version 1.0), at scale 1:1 million, was compiled based on the soil map of Malawi at scale 1:250,000 (compiled by the Land Resources Evaluation Project) that was complemented with soil boundary information from the provisional soil map at scale 1:1 million.

  10. Modeling wake effects in large wind farms in complex terrain: the problem, the methods and the issues

    DEFF Research Database (Denmark)

    Politis, E.S.; Prospathopoulos, J.; Cabezon, D.

    2012-01-01

    Computational fluid dynamic (CFD) methods are used in this paper to predict the power production from entire wind farms in complex terrain and to shed some light into the wake flow patterns. Two full three-dimensional Navier–Stokes solvers for incompressible fluid flow, employing k - ε and k - ω...... of the work being undertaken within the UpWind Integrated Project that aims to develop the design tools for next generation of large wind turbines. In this part of UpWind, the performance of wind farm and wake models is being examined in complex terrain environment where there are few pre-existing relevant...... measurements. The focus of the work being carried out is to evaluate the performance of CFD models in large wind farm applications in complex terrain and to examine the development of the wakes in a complex terrain environment....

  11. Terrain-surface Estimation from Body Configurations of Passive Linkages

    Directory of Open Access Journals (Sweden)

    Daisuke Chugo

    2014-02-01

    Full Text Available A passive linkage mechanism is used for increasing the mobile performance of a wheeled vehicle on uneven ground. The mechanism changes its shape according to the terrain and enables all the wheels to remain grounded while the vehicle operates over rough terrain. This means that the shape of the passive linkage mechanism must correspond to that of the terrain surface, so that the vehicle can estimate the shape of the surface while passing over it. This paper proposes a new terrain-surface estimation scheme that uses a passive linkage mechanism. Our key concept is to enable changes in the vehicle body's configuration to correspond to those in the terrain's shape. Using this concept, our mobile platform estimates the shape of terrain surfaces without using external sensors; the estimated surface shapes are used to adjust the reference velocities of individual wheels, thereby improving the mobile performance of the vehicle. We test our proposed scheme by experiments using a prototype vehicle.

  12. Integrating Terrain Maps Into a Reactive Navigation Strategy

    Science.gov (United States)

    Howard, Ayanna; Werger, Barry; Seraji, Homayoun

    2006-01-01

    An improved method of processing information for autonomous navigation of a robotic vehicle across rough terrain involves the integration of terrain maps into a reactive navigation strategy. Somewhat more precisely, the method involves the incorporation, into navigation logic, of data equivalent to regional traversability maps. The terrain characteristic is mapped using a fuzzy-logic representation of the difficulty of traversing the terrain. The method is robust in that it integrates a global path-planning strategy with sensor-based regional and local navigation strategies to ensure a high probability of success in reaching a destination and avoiding obstacles along the way. The sensor-based strategies use cameras aboard the vehicle to observe the regional terrain, defined as the area of the terrain that covers the immediate vicinity near the vehicle to a specified distance a few meters away.

  13. Morphological modeling of terrains and volume data

    CERN Document Server

    Comic, Lidija; Magillo, Paola; Iuricich, Federico

    2014-01-01

    This book describes the mathematical background behind discrete approaches to morphological analysis of scalar fields, with a focus on Morse theory and on the discrete theories due to Banchoff and Forman. The algorithms and data structures presented are used for terrain modeling and analysis, molecular shape analysis, and for analysis or visualization of sensor and simulation 3D data sets. It covers a variety of application domains including geography, geology, environmental sciences, medicine and biology. The authors classify the different approaches to morphological analysis which are all ba

  14. UNIFIED REPRESENTATION FOR COLLABORATIVE VISUALIZATION OF PLANETARY TERRAIN DATA Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to apply to planetary terrain mapping an alternative, multiresolution method, subdivision surfaces (subdivs), in place of conventional digital elevation...

  15. LUNAR TERRAIN AND ALBEDO RECONSTRUCTION FROM APOLLO IMAGERY

    Data.gov (United States)

    National Aeronautics and Space Administration — LUNAR TERRAIN AND ALBEDO RECONSTRUCTION FROM APOLLO IMAGERY ARA V NEFIAN*, TAEMIN KIM, MICHAEL BROXTON, AND ZACH MORATTO Abstract. Generating accurate three...

  16. Functional Decomposition of Modeling and Simulation Terrain Database Generation Process

    National Research Council Canada - National Science Library

    Yakich, Valerie R; Lashlee, J. D

    2008-01-01

    .... This report documents the conceptual procedure as implemented by Lockheed Martin Simulation, Training, and Support and decomposes terrain database construction using the Integration Definition for Function Modeling (IDEF...

  17. Tool for Viewing Faults Under Terrain

    Science.gov (United States)

    Siegel, Herbert, L.; Li, P. Peggy

    2005-01-01

    Multi Surface Light Table (MSLT) is an interactive software tool that was developed in support of the QuakeSim project, which has created an earthquake- fault database and a set of earthquake- simulation software tools. MSLT visualizes the three-dimensional geometries of faults embedded below the terrain and animates time-varying simulations of stress and slip. The fault segments, represented as rectangular surfaces at dip angles, are organized into collections, that is, faults. An interface built into MSLT queries and retrieves fault definitions from the QuakeSim fault database. MSLT also reads time-varying output from one of the QuakeSim simulation tools, called "Virtual California." Stress intensity is represented by variations in color. Slips are represented by directional indicators on the fault segments. The magnitudes of the slips are represented by the duration of the directional indicators in time. The interactive controls in MSLT provide a virtual track-ball, pan and zoom, translucency adjustment, simulation playback, and simulation movie capture. In addition, geographical information on the fault segments and faults is displayed on text windows. Because of the extensive viewing controls, faults can be seen in relation to one another, and to the terrain. These relations can be realized in simulations. Correlated slips in parallel faults are visible in the playback of Virtual California simulations.

  18. Basalt: Biologic Analog Science Associated with Lava Terrains

    Science.gov (United States)

    Lim, D. S. S.; Abercromby, A.; Kobs-Nawotniak, S. E.; Kobayashi, L.; Hughes, S. S.; Chappell, S.; Bramall, N. E.; Deans, M. C.; Heldmann, J. L.; Downs, M.; Cockell, C. S.; Stevens, A. H.; Caldwell, B.; Hoffman, J.; Vadhavk, N.; Marquez, J.; Miller, M.; Squyres, S. W.; Lees, D. S.; Fong, T.; Cohen, T.; Smith, T.; Lee, G.; Frank, J.; Colaprete, A.

    2015-12-01

    This presentation will provide an overview of the BASALT (Biologic Analog Science Associated with Lava Terrains) program. BASALT research addresses Science, Science Operations, and Technology. Specifically, BASALT is focused on the investigation of terrestrial volcanic terrains and their habitability as analog environments for early and present-day Mars. Our scientific fieldwork is conducted under simulated Mars mission constraints to evaluate strategically selected concepts of operations (ConOps) and capabilities with respect to their anticipated value for the joint human and robotic exploration of Mars. a) Science: The BASALT science program is focused on understanding habitability conditions of early and present-day Mars in two relevant Mars-analog locations (the Southwest Rift Zone (SWRZ) and the East Rift Zone (ERZ) flows on the Big Island of Hawai'i and the eastern Snake River Plain (ESRP) in Idaho) to characterize and compare the physical and geochemical conditions of life in these environments and to learn how to seek, identify, and characterize life and life-related chemistry in basaltic environments representing these two epochs of martian history. b) Science Operations: The BASALT team will conduct real (non-simulated) biological and geological science at two high-fidelity Mars analogs, all within simulated Mars mission conditions (including communication latencies and bandwidth constraints) that are based on current architectural assumptions for Mars exploration missions. We will identify which human-robotic ConOps and supporting capabilities enable science return and discovery. c) Technology: BASALT will incorporate and evaluate technologies in to our field operations that are directly relevant to conducting the scientific investigations regarding life and life-related chemistry in Mars-analogous terrestrial environments. BASALT technologies include the use of mobile science platforms, extravehicular informatics, display technologies, communication

  19. An Investigation of the Hypotheses for Formation of the Platy-Ridged Terrain in Elysium Planitia, Mars

    Science.gov (United States)

    Yue, Z.; Gou, S.; Michael, G.; Di, K.; Xie, H.; Gong, H.; Shao, Y.

    2017-07-01

    The origin of the platy-ridged-polygonized (PRP) terrains on Martian surface has long been debated. The terrain has generally been classified as water, pack ice, or basalt lava related flow. The crater counting results of the PRP terrains suggest they are geologically very young; therefore, they are significant in understanding the recent evolution of Mars. This work evaluated the current hypotheses through detailed analysis of the distribution and microtopographies with the High Resolution Imaging Science Experiment (HiRISE) images for the PRP terrains in Elysium Planitia, Mars. Quantitative measurements and statistics of the typical features of the PRP terrains were also made. In addition, we also found an analog site in Tarim Basin in Xinjiang, China. Our results suggest that mud flow is responsible for the formation of the PRP terrains on the Mars surface, although the hypothesis of low-viscosity basalt lava floods cannot be completely excluded. This finding implies that a regional environment suitable for liquid water may have existed in recent geologic time, which has great importance for future Mars scientific exploration.

  20. AN INVESTIGATION OF THE HYPOTHESES FOR FORMATION OF THE PLATY-RIDGED-POLYGONIZED TERRAIN IN ELYSIUM PLANITIA, MARS

    Directory of Open Access Journals (Sweden)

    Z. Yue

    2017-07-01

    Full Text Available The origin of the platy-ridged-polygonized (PRP terrains on Martian surface has long been debated. The terrain has generally been classified as water, pack ice, or basalt lava related flow. The crater counting results of the PRP terrains suggest they are geologically very young; therefore, they are significant in understanding the recent evolution of Mars. This work evaluated the current hypotheses through detailed analysis of the distribution and microtopographies with the High Resolution Imaging Science Experiment (HiRISE images for the PRP terrains in Elysium Planitia, Mars. Quantitative measurements and statistics of the typical features of the PRP terrains were also made. In addition, we also found an analog site in Tarim Basin in Xinjiang, China. Our results suggest that mud flow is responsible for the formation of the PRP terrains on the Mars surface, although the hypothesis of low-viscosity basalt lava floods cannot be completely excluded. This finding implies that a regional environment suitable for liquid water may have existed in recent geologic time, which has great importance for future Mars scientific exploration.

  1. Wind modelling over complex terrain using CFD

    Science.gov (United States)

    Avila, Matias; Owen, Herbert; Folch, Arnau; Prieto, Luis; Cosculluela, Luis

    2015-04-01

    The present work deals with the numerical CFD modelling of onshore wind farms in the context of High Performance Computing (HPC). The CFD model involves the numerical solution of the Reynolds-Averaged Navier-Stokes (RANS) equations together with a κ-ɛ turbulence model and the energy equation, specially designed for Atmospheric Boundary Layer (ABL) flows. The aim is to predict the wind velocity distribution over complex terrain, using a model that includes meteorological data assimilation, thermal coupling, forested canopy and Coriolis effects. The modelling strategy involves automatic mesh generation, terrain data assimilation and generation of boundary conditions for the inflow wind flow distribution up to the geostrophic height. The CFD model has been implemented in Alya, a HPC multi physics parallel solver able to run with thousands of processors with an optimal scalability, developed in Barcelona Supercomputing Center. The implemented thermal stability and canopy physical model was developed by Sogachev in 2012. The k-ɛ equations are of non-linear convection diffusion reaction type. The implemented numerical scheme consists on a stabilized finite element formulation based on the variational multiscale method, that is known to be stable for this kind of turbulence equations. We present a numerical formulation that stresses on the robustness of the solution method, tackling common problems that produce instability. The iterative strategy and linearization scheme is discussed. It intends to avoid the possibility of having negative values of diffusion during the iterative process, which may lead to divergence of the scheme. These problems are addressed by acting on the coefficients of the reaction and diffusion terms and on the turbulent variables themselves. The k-ɛ equations are highly nonlinear. Complex terrain induces transient flow instabilities that may preclude the convergence of computer flow simulations based on steady state formulation of the

  2. Archaean TTG of Vodlozero Terrain, Fennoscandian Shield

    Science.gov (United States)

    Chekulaev, Valery; Arestova, Natalia

    2014-05-01

    The Vodlozero terrain is the largest (about 270*240 km) early Archaean fragment of Fennoscandian Shield and composes its eastern part. The granitoids of TTG suite are predominant component of the terrain. The greenstone belts are placed along the margins of the terrain. Several stages of TTG formation can be distinguished in Achaean crust history. (1) The oldest TTG are trondhjemites and tonalities with age of 3240 Ma. They contain rare and small amphibolite inclusions of the same age. These TTG are characterized by high Sr (av. 412 ppm), Sr/Y (70), (La/Yb)n (54) and low Y (av. 7 ppm), Yb (0.32 ppm) and Nb (4 ppm). It was shown (Lobach-Zhuchenko et al., 2000), that the source of these TTG could be basic rocks, having composition similar with TH1 by K.Condie. (2) The tonalities and granodiorites with age of 3150 Ma are disposed near greenstone belts and contain compared to TTG of the first group less Sr (av. 250 ppm), Sr/Y (22), (La/Yb)n (18) and more K, Rb (av. 70 ppm), Ba (470 ppm), Y (11 ppm),Yb (1.16 ppm). TTG of both groups have identical T(DM)Nd (3250-3400 Ma) and differences in composition is evidently connected with lower level of source melting of the second group and also with K-metasomatism. The volcanics of the greenstone belts have age 3020 - 2940 Ma. Dykes of gabbro-amphibolites and andesites with the same age and composition cut TTG of the first and the second groups. The age of the third TTG group is about 2900 Ma ago. These rocks form leucosoma of migmatites within TTG of the second group. The composition of the third TTG and Nd isotope data suppose their origin by the melting of ancient TTG crust simultaneously with greenstone belt emplacement. The fourth TTG group with age 2780-2850 Ma forms a small intrusions, cutting older TTG and greenstone rocks. Their composition is similar to 3150 Ma TTG. Nd isotope data indicate that these TTG have younger (about 2850 Ma) source. Thus there are four TTG groups formed into interval more 400 Ma. The age and

  3. 75 FR 5767 - All Terrain Vehicle Chinese Language Webinar; Meeting

    Science.gov (United States)

    2010-02-04

    ... COMMISSION All Terrain Vehicle Chinese Language Webinar; Meeting AGENCY: Consumer Product Safety Commission... Terrain Vehicle Chinese Language Webinar. The webinar will focus on CPSC's requirements for ATV's.... Chinese language speakers can access the webinar at http://www.cpsc.gov/webcast/index_ch.html . English...

  4. Large-Eddy Simulation of turbine wake in complex terrain

    DEFF Research Database (Denmark)

    Berg, Jacob; Troldborg, Niels; Sørensen, Niels N.

    2017-01-01

    We present Large-Eddy Simulation results of a turbine wake in realistic complex terrain with slopes above 0.5. By comparing simulations including and without the wind turbine we can estimate the induction factor, a, and we show how the presence of a strong recirculation zone in the terrain dictates...

  5. Terrain Perception in a Shape Shifting Rolling-Crawling Robot

    Directory of Open Access Journals (Sweden)

    Fuchida Masataka

    2016-09-01

    Full Text Available Terrain perception greatly enhances the performance of robots, providing them with essential information on the nature of terrain being traversed. Several living beings in nature offer interesting inspirations which adopt different gait patterns according to nature of terrain. In this paper, we present a novel terrain perception system for our bioinspired robot, Scorpio, to classify the terrain based on visual features and autonomously choose appropriate locomotion mode. Our Scorpio robot is capable of crawling and rolling locomotion modes, mimicking Cebrenus Rechenburgi, a member of the huntsman spider family. Our terrain perception system uses Speeded Up Robust Feature (SURF description method along with color information. Feature extraction is followed by Bag of Word method (BoW and Support Vector Machine (SVM for terrain classification. Experiments were conducted with our Scorpio robot to establish the efficacy and validity of the proposed approach. In our experiments, we achieved a recognition accuracy of over 90% across four terrain types namely grass, gravel, wooden deck, and concrete.

  6. What Influences Youth to Operate All-Terrain Vehicles Safely?

    Science.gov (United States)

    Grummon, A. H.; Heaney, C. A.; Dellinger, W. A.; Wilkins, J. R., III

    2014-01-01

    The operation of all-terrain vehicles (ATVs) by youth has contributed to the incidence of serious and fatal injuries among children. This study explored factors related to the frequency with which youth wore a helmet and refrained from engaging in three risky driving behaviors (driving at risky speeds, on paved roads and on unfamiliar terrain)…

  7. Investigating the effect of different terrain modeling techniques on the computation of local gravity anomalies

    Science.gov (United States)

    Tsoulis, Dimitrios; Patlakis, Konstantinos

    2017-04-01

    Gravity reductions and gravity anomalies express important tools for the analysis and interpretation of real gravity measurements at all spatial scales. Simple geometries of planar or spherical slabs for the topographic masses underlying the computation point down to a reference height surface produce the traditional definition of simple Bouguer anomalies. However, especially for gravity measurements obtained from local gravity surveys stretching up to only a few tens of kilometers, a detailed consideration of the deviations of the surface topographic relief from the ideal slab geometry is required and necessary in order to obtain the so-called refined Bouguer anomalies. The present contribution examines the further refinement of these computations depending on the exact geometric representation of the topographic surface and the corresponding masses defining the terrain correction quantity. Using as input data 328 surface gravity observations and a 20 km x 15 km Digital Terrain Model with a 50 m x 50 m spatial resolution of a steep terrain area in the Bavarian Alps different sets of gravity anomalies were computed from different geometrical and mathematical approximations of the topographic masses and its corresponding gravitational effect. Right rectangular prisms, polyhedrons, bilinear surfaces, mass-line and mass-prism FFT representations of the terrain effect have been implemented for the evaluation of refined Bouguer gravity anomalies over the 20 km x 15 km region and the computed grids have been compared both against each other as well as with respect to the topographic height.

  8. Uncertainty into statistical landslide susceptibility models resulting from terrain mapping units and landslide input data

    Science.gov (United States)

    Zêzere, José Luis; Pereira, Susana; Melo, Raquel; Oliveira, Sérgio; Garcia, Ricardo

    2017-04-01

    There are multiple sources of uncertainty within statistically-based landslide susceptibility assessment that needs to be accounted and monitored. In this work we evaluate and discuss differences observed on landslide susceptibility maps resulting from the selection of the terrain mapping unit and the selection of the feature type to represent landslides (polygon vs point). The work is performed in the Silveira Basin (18.2 square kilometres) located north of Lisbon, Portugal, using a unique database of geo-environmental landslide predisposing factors and an inventory of 81 shallow translational slides. The Logistic Regression is the statistical method selected to combine the predictive factors with the dependent variable. Four landslide susceptibility models were computed using the complete landslide inventory and considering the total landslide area over four different terrain mapping units: Slope Terrain Units (STU), Geo-Hydrological Terrain Units (GHTU), Census Terrain Units (CTU) and Grid Cell Terrain Units (GCTU). Four additional landslide susceptibility models were made over the same four terrain mapping units using a landslide training group (50% of the inventory randomly selected). These models were independently validated with the other 50% of the landslide inventory (landslide test group). Lastly, two additional landslide susceptibility models were computed over GCTU, one using the landslide training group represented as point features corresponding to the centroid of landslide, and other using the centroid of landslide rupture zone. In total, 10 landslide susceptibility maps were constructed and classified in 10 classes of equal number of terrain units to allow comparison. The evaluation of the prediction skills of susceptibility models was made using ROC metrics and Success and Prediction rate curves. Lastly, the landslide susceptibility maps computed over GCTU were compared using the Kappa statistics. With this work we conclude that large differences

  9. Conically scanning lidar error in complex terrain

    Directory of Open Access Journals (Sweden)

    Ferhat Bingöl

    2009-05-01

    Full Text Available Conically scanning lidars assume the flow to be homogeneous in order to deduce the horizontal wind speed. However, in mountainous or complex terrain this assumption is not valid implying a risk that the lidar will derive an erroneous wind speed. The magnitude of this error is measured by collocating a meteorological mast and a lidar at two Greek sites, one hilly and one mountainous. The maximum error for the sites investigated is of the order of 10 %. In order to predict the error for various wind directions the flows at both sites are simulated with the linearized flow model, WAsP Engineering 2.0. The measurement data are compared with the model predictions with good results for the hilly site, but with less success at the mountainous site. This is a deficiency of the flow model, but the methods presented in this paper can be used with any flow model.

  10. Groundwater flood hazards in lowland karst terrains

    Science.gov (United States)

    Naughton, Owen; McCormack, Ted

    2016-04-01

    The spatial and temporal complexity of flooding in karst terrains pose unique flood risk management challenges. Lowland karst landscapes can be particularly susceptible to groundwater flooding due to a combination of limited drainage capacity, shallow depth to groundwater and a high level of groundwater-surface water interactions. Historically the worst groundwater flooding to have occurred in the Rep. of Ireland has been centred on the Gort Lowlands, a karst catchment on the western coast of Ireland. Numerous notable flood events have been recorded throughout the 20th century, but flooding during the winters of 2009 and 2015 were the most severe on record, inundating an area in excess of 20km2 and causing widespread and prolonged disruption and damage to property and infrastructure. Effective flood risk management requires an understanding of the recharge, storage and transport mechanisms during flood conditions, but is often hampered by a lack of adequate data. Using information gathered from the 2009 and 2015 events, the main hydrological and geomorphological factors which influence flooding in this complex lowland karst groundwater system under are elucidated. Observed flood mechanisms included backwater flooding of sinks, overland flow caused by the overtopping of sink depressions, high water levels in turlough basins, and surface ponding in local epikarst watersheds. While targeted small-scale flood measures can locally reduce the flood risk associated with some mechanisms, they also have the potential to exacerbate flooding down-catchment and must be assessed in the context of overall catchment hydrology. This study addresses the need to improve our understanding of groundwater flooding in karst terrains, in order to ensure efficient flood prevention and mitigation in future and thus help achieve the aims of the EU Floods Directive.

  11. Qualitative analysis of wind-turbine wakes over hilly terrain

    Science.gov (United States)

    Hyvärinen, A.; Segalini, A.

    2017-05-01

    In this work, wind-turbine wakes are studied over flat and hilly terrains. Measurements made by using stereoscopic PIV are compared to data obtained from numerical simulations using RANS equations and an actuator-disc method. The numerical and experimental data show similar qualitative trends, indicating that the wind-turbine wake is perturbed by the presence of the hills. Additionally, a faster flow recovery at hub height is seen with the hilly terrain, indicating that the hills presence is beneficial for downstream turbines exposed to wake-interaction effects. The Jensen wake model is implemented over the hilly terrain and it is shown that this model cannot accurately capture the wake modulations induced by the hills. However, by superimposing a wind-turbine wake simulated over flat terrain on the hilly-terrain flow field, it is illustrated that the commonly-used wake-superposition technique can yield reasonable results if the used wake model has sufficient accuracy.

  12. Statistical Modeling of Robotic Random Walks on Different Terrain

    Science.gov (United States)

    Naylor, Austin; Kinnaman, Laura

    Issues of public safety, especially with crowd dynamics and pedestrian movement, have been modeled by physicists using methods from statistical mechanics over the last few years. Complex decision making of humans moving on different terrains can be modeled using random walks (RW) and correlated random walks (CRW). The effect of different terrains, such as a constant increasing slope, on RW and CRW was explored. LEGO robots were programmed to make RW and CRW with uniform step sizes. Level ground tests demonstrated that the robots had the expected step size distribution and correlation angles (for CRW). The mean square displacement was calculated for each RW and CRW on different terrains and matched expected trends. The step size distribution was determined to change based on the terrain; theoretical predictions for the step size distribution were made for various simple terrains. It's Dr. Laura Kinnaman, not sure where to put the Prefix.

  13. Slip estimation methods for proprioceptive terrain classification using tracked mobile robots

    CSIR Research Space (South Africa)

    Masha, Ditebogo F

    2017-11-01

    Full Text Available Recent work has shown that proprioceptive measurements such as terrain slip can be used for terrain classification. This paper investigates the suitability of four simple slip estimation methods for differentiating between indoor and outdoor terrain...

  14. Development of a Portable Data Acquisition System for Human Performance Assessment in the Field - Phase IIB Validation (Mise au Point d’un Systeme Portatif D’Acquisition de Donnees Pour L’Evaluation de la Performance Humaine sur le Terrain Phase IIB Validation)

    Science.gov (United States)

    2007-12-01

    d’évaluer le type et l’intensité des travaux réalisés par une personne sur le terrain, p. ex. un soldat qui participe à un exercice d’entraînement. Deux...le type et l’intensité des travaux réalisés par une personne sur le terrain, p. ex. un soldat qui participe à un exercice d’entraînement. Deux types

  15. Environmental Impacts of Forest Road Construction on Mountainous Terrain

    Directory of Open Access Journals (Sweden)

    Erhan Caliskan

    2013-03-01

    Full Text Available Forest roads are the base infrastructure foundation of forestry operations. These roads entail a complex engineering effort because they can cause substantial environmental damage to forests and include a high-cost construction. This study was carried out in four sample sites of Giresun, Trabzon(2 and Artvin Forest Directorate, which is in the Black Sea region of Turkey. The areas have both steep terrain (30-50% gradient and very steep terrain (51-80% gradient. Bulldozers and hydraulic excavators were determined to be the main machines for forest road construction, causing environmental damage and cross sections in mountainous areas.As a result of this study, the percent damage to forests was determined as follows: on steep terrain, 21% of trees were damaged by excavators and 33% of trees were damaged by bulldozers during forest road construction, and on very steep terrain, 27% of trees were damaged by excavators and 44% of trees were damaged by bulldozers during forest road construction. It was also determined that on steep terrain, when excavators were used, 12.23% less forest area was destroyed compared with when bulldozers were used and 16.13% less area was destroyed by excavators on very steep terrain. In order to reduce the environmental damage on the forest ecosystem, especially in steep terrains, hydraulic excavators should replace bulldozers in forest road construction activities.

  16. Routing, construction and maintenance of pipelines in landslide terrain

    Energy Technology Data Exchange (ETDEWEB)

    Stepanek, M. [Geo-Enginering (M.S.T.) Ltd., Calgary, AB (Canada)

    1999-07-01

    Factors influencing the location and routing of pipelines, and the effects of unstable terrain features on construction and maintenance are discussed. Examples from northwestern Alberta and northeastern British Columbia are cited to illustrate the various techniques, such as overhead crossings of valleys and directional drilling to install pipelines below streams, adopted by pipeline construction companies to deal with the challenges presented by sensitive and unstable terrain. The case histories cited also serve to emphasize the importance of terrain analysis and the proper identification of potential problem areas. 5 refs., 7 figs.

  17. Hybrid RANS/LES applied to complex terrain

    DEFF Research Database (Denmark)

    Bechmann, Andreas; Sørensen, Niels N.

    2011-01-01

    Large Eddy Simulation (LES) of the wind in complex terrain is limited by computational cost. The number of computational grid points required to resolve the near-ground turbulent structures (eddies) are very high. The traditional solution to the problem has been to apply a wall function...... aspect ratio in the RANS layer and thereby resolve the mean near-wall velocity profile. The method is applicable to complex terrain and the benefits of traditional LES are kept intact. Using the hybrid method, simulations of the wind over a natural complex terrain near Wellington in New Zealand...

  18. Petite motorisation et exploitations maraîchères de taille limitée du Sahel tunisien Partie 2: Evaluation sur le terrain des performances et des coûts de préparation du sol

    Directory of Open Access Journals (Sweden)

    Chehaibi, S.

    2003-01-01

    Full Text Available Low Power Mechanisation and Small-scale Vegetable Production in the Tunisian Sahel Region. Part 2: On the Field Evaluation of Performances and of Soil Preparation Costs. In this study, it was investigated to what extent low power mechanisation could be introduced in vegetable production in the Tunisian Sahel region by evaluating its performance (labour input and field efficiency by means of field experiments in which different traction equipment was used for carrying out several cultivation operations. Furthermore, costs per unit area for soil preparation in both sandy clay and clayish sand were calculated for four different power classes and for small fields. The results showed that two wheel tractors had a real labour input for scuffling between plant rows ranging from 11.3 h/ha to 18.7 h/ha. These inputs ranged from 5.5 h/ha to 6.7 h/ha for tied crops. For mowing, the two wheel tractor had labour inputs of 17.3 and 14.2 h/ha for the first and the second cut, respectively, while for potato digging, the first and the second passage of secondary tillage these values were 11.5, 14.3 and 10.4 h/ha, respectively. Superficial soil preparation by means of a four wheel tractor gave rise to values between 2.7 and 3.5 h/ha. With respect to the cost estimation for soil preparation, the lowest costs were obtained by means of the low power mechanisation. Similar conclusions were drawn for the field efficiencies for the operations investigated. In general, these efficiencies were above 70%.

  19. Enhanced perception of terrain hazards in off-road path choice: stereoscopic 3D versus 2D displays

    Science.gov (United States)

    Merritt, John O.; CuQlock-Knopp, V. Grayson; Myles, Kimberly

    1997-06-01

    Off-road mobility at night is a critical factor in modern military operations. Soldiers traversing off-road terrain, both on foot and in combat vehicles, often use 2D viewing devices (such as a driver's thermal viewer, or biocular or monocular night-vision goggles) for tactical mobility under low-light conditions. Perceptual errors can occur when 2D displays fail to convey adequately the contours of terrain. Some off-road driving accidents have been attributed to inadequate perception of terrain features due to using 2D displays (which do not provide binocular-parallax cues to depth perception). In this study, photographic images of terrain scenes were presented first in conventional 2D video, and then in stereoscopic 3D video. The percentage of possible correct answers for 2D and 3D were: 2D pretest equals 52%, 3D pretest equals 80%, 2D posttest equals 48%, 3D posttest equals 78%. Other recent studies conducted at the US Army Research Laboratory's Human Research and Engineering Directorate also show that stereoscopic 3D displays can significantly improve visual evaluation of terrain features, and thus may improve the safety and effectiveness of military off-road mobility operation, both on foot and in combat vehicles.

  20. Lunar All-Terrain Utility Vehicle for EVA Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ProtoInnovations, LLC proposes to develop a new type of planetary rover called a Lunar All-terrain Utility Vehicle ("LATUV") to assist extra-vehicular activities in...

  1. DCS Terrain Submission for Hunterdon County New Jersey

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. Classification of Mars Terrain Using Multiple Data Sources

    Data.gov (United States)

    National Aeronautics and Space Administration — Classification of Mars Terrain Using Multiple Data Sources Alan Kraut1, David Wettergreen1 ABSTRACT. Images of Mars are being collected faster than they can be...

  3. Lunar All-Terrain Utility Vehicle for EVA Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ProtoInnovations, LLC proposes to develop a new type of planetary rover called a Lunar All-terrain Utility Vehicle ("Lunar ATV") to assist extra-vehicular activities...

  4. DCS Terrain for Chatham Co GA (FY2010)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  5. DCS Terrain for Effingham Co GA (FY2010)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  6. Bladed Terrain on Pluto: Possible Origins and Evolution

    Science.gov (United States)

    Moore, J. M.; Howard, A. D.; Umurhan, O. M.; White, O. L.; Schenk, P. M.; Beyer, R. A.; Grundy, W. M.; Young, L. A.; Stern, S. A.; Weaver, H. A.; hide

    2017-01-01

    We conclude that Bladed Terrain on Pluto is a deposit of massive CH4, which preferentially precipitates at high elevations, and has since its initial formation, undergone episodes of sublimation erosion that has given this deposit its characteristic texture.

  7. Weather in Mountainous Terrain (Overcoming Scientific Barriers to Weather Support)

    Science.gov (United States)

    2011-02-15

    Weather in Mountainous Terrain (Overcoming Scientific Barriers to Weather Support) Fiesta Resort & Conference Center Tempe, AZ February 1...Meteorology Overcoming Scientific Barriers to Weather Support Fiesta Resort & Conference Center Tempe, AZ February 1 & 2, 2010 Hosted by University

  8. DCS Terrain Submission for Clay County, AR, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. TERRAIN DATA CAPTURE STANDARDS, LUZERNE COUNTY, PA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data includes digital elevation models, LIDAR derived contours, LIDAR three-dimensional spot elevations and breaklines, field surveyed ground elevations and...

  10. Laser altimetry and terrain analysis: A revolution in geomorphology

    NARCIS (Netherlands)

    Anders, N.; Seijmonsbergen, H.

    2008-01-01

    Terrain analysis in geomorphology has undergone a serious quantitative revolution over recent decades. Lidar information has been efficiently used to automatically classify discrete landforms, map forest structures, and provide input for models simulating landscape development, e.g. channel incision

  11. DCS Terrain for Tift County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  12. DCS Terrain Submission for Eau Claire County, Wisconsin

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. DCS Terrain Submission for Johnson County, AR, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. TERRAIN DATA, DELANEY CREEK WATERSHED, HILLSBOROUGH COUNTY, FL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

  15. TERRAIN, CITY OF SEWARD, KENAI PENINSULA BOROUGH, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. DCS Terrain Submission for Pine County, MN (Countywide DFIRM)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  17. TERRAIN, City of El Dorado, Butler County, KS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  18. DCS Terrain Submittal for Washita County, Oklahoma, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  19. Terrain, BIG BLUE RIVER TRIBUTARY NO 44, GAGE COUNTY, NE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  20. DCS Terrain Submission for Randolph County, AR, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. DCS Terrain Submission for Jackson County, AR, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. DCS Terrain Submission for McCook County, SD

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

  3. DCS Terrain Submission for La Paz County, AZ

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

  4. DCS Terrain Submission for Los Angeles County, CA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. DCS Terrain Submittal for Macon County, Georgia, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  6. DCS Terrain Submission for Lake Kaweah PMR - Tulare County, California

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  7. DCS Terrain Submission for Monmouth County, New Jersey

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  8. Cross-Coupled Control for All-Terrain Rovers

    Directory of Open Access Journals (Sweden)

    Giulio Reina

    2013-01-01

    Full Text Available Mobile robots are increasingly being used in challenging outdoor environments for applications that include construction, mining, agriculture, military and planetary exploration. In order to accomplish the planned task, it is critical that the motion control system ensure accuracy and robustness. The achievement of high performance on rough terrain is tightly connected with the minimization of vehicle-terrain dynamics effects such as slipping and skidding. This paper presents a cross-coupled controller for a 4-wheel-drive/4-wheel-steer robot, which optimizes the wheel motors’ control algorithm to reduce synchronization errors that would otherwise result in wheel slip with conventional controllers. Experimental results, obtained with an all-terrain rover operating on agricultural terrain, are presented to validate the system. It is shown that the proposed approach is effective in reducing slippage and vehicle posture errors.

  9. Cross-coupled control for all-terrain rovers.

    Science.gov (United States)

    Reina, Giulio

    2013-01-08

    Mobile robots are increasingly being used in challenging outdoor environments for applications that include construction, mining, agriculture, military and planetary exploration. In order to accomplish the planned task, it is critical that the motion control system ensure accuracy and robustness. The achievement of high performance on rough terrain is tightly connected with the minimization of vehicle-terrain dynamics effects such as slipping and skidding. This paper presents a cross-coupled controller for a 4-wheel-drive/4-wheel-steer robot, which optimizes the wheel motors' control algorithm to reduce synchronization errors that would otherwise result in wheel slip with conventional controllers. Experimental results, obtained with an all-terrain rover operating on agricultural terrain, are presented to validate the system. It is shown that the proposed approach is effective in reducing slippage and vehicle posture errors.

  10. DCS Terrain Submittal for Pike County, Georgia, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  11. DCS Terrain Submittal for Taylor County, Georgia, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  12. DCS Terrain for Montgomery County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  13. DCS Terrain Submittal for Crisp County, Georgia, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. DCS Terrain Submission for Chippewa County, MI (Countywide DFIRM)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  15. DCS Terrain Submittal for Mitchell County, Georgia, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. DCS Terrain for Wilcox County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  17. DCS TERRAIN SUBMISSION for MORRIS COUNTY, NEW JERSEY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that were used to create...

  18. CITY OF RADFORD TERRAIN, CITY OF RADFORD, VA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data includes digital elevation models, LIDAR derived contours, LIDAR three-dimensional spot elevations and breaklines, field surveyed ground elevations and...

  19. LandingNav: Terrain Guided Automated Precision Landing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase I effort successfully demonstrated the feasibility of a terrain guided automated precision landing sensor using an innovative multi-field-of-view stereo...

  20. DCS Terrain Submittal for Thomas County, Georgia, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. DCS Terrain Submission for New Castle County, DE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. Calibrated L-Band Terrain Measurements and Analysis Program.

    Science.gov (United States)

    1986-02-01

    space of these three parameters, points corresponding to samples from different terrain types will be well separated. And not only will points for...different terrain types be quite distinct, but also dif- ferent regions of the three-parameter space will characterize differ- ent surface types. The...planned to examine goodness of fit of both the IG and log- 4-4 normal distributions to histograms based on various samples, using 86 the Kolmogoroff -Smirnov

  3. Hexapod Walking Robot Energy Consumption Dependence On Different Gaits And Speed While Moving On Even Terrain

    Directory of Open Access Journals (Sweden)

    Mindaugas Luneckas

    2014-05-01

    Full Text Available Evaluation of robotic energetics while moving on rough terrain becomes a difficult task without having the information about the movement on even terrain. The problem appears in selection of gaits depending on how much power robot consumes. In this paper, energy consumption of a hexapod walking robot dependence on different gaits and speed is observed. Three most common gaits were used in this experiment: tripod gait, bipod gait and wave gait. Results clearly show that while moving at slow speed, the least energy is consumed by wave gait. As the speed increases, bipod gait selection is required to lower energy consumption. Finally, tripod gait must be selected at even higher speed.

  4. Learned navigation in unknown terrains: A retraction method

    Science.gov (United States)

    Rao, Nageswara S. V.; Stoltzfus, N.; Iyengar, S. Sitharama

    1989-01-01

    The problem of learned navigation of a circular robot R, of radius delta (is greater than or equal to 0), through a terrain whose model is not a-priori known is considered. Two-dimensional finite-sized terrains populated by an unknown (but, finite) number of simple polygonal obstacles are also considered. The number and locations of the vertices of each obstacle are unknown to R. R is equipped with a sensor system that detects all vertices and edges that are visible from its present location. In this context two problems are covered. In the visit problem, the robot is required to visit a sequence of destination points, and in the terrain model acquisition problem, the robot is required to acquire the complete model of the terrain. An algorithmic framework is presented for solving these two problems using a retraction of the freespace onto the Voronoi diagram of the terrain. Algorithms are then presented to solve the visit problem and the terrain model acquisition problem.

  5. Stratigraphy of the layered terrain in Valles Marineris, Mars

    Science.gov (United States)

    Komatsu, G.; Strom, Roger G.

    1991-01-01

    The layered terrain in Valles Marineris provides information about its origin and the geologic history of this canyon system. Whether the terrain is sedimentary material deposited in a dry or lacustrine environment, or volcanic material related to the tectonics of the canyon is still controversial. However, recent studies of Gangis Layered Terrain suggests a cyclic sequence of deposition and erosion under episodic lacustrine conditions. The stratigraphic studies are extended to four other occurrences of layered terrains in Valles Marineris in an attempt to correlate and distinguish between depositional environments. The Juvantae Chasma, Hebes Chasma, Ophir and Candor Chasmata, Melas Chasma, and Gangis Layered Terrain were examined. Although there are broad similarities among the layered terrains, no two deposits are exactly alike. This suggests that there was no synchronized regional depositional processes to form all the layered deposits. However, the similar erosional style of the lower massive weakly bedded unit in Hebes, Gangis, and Ophir-Candor suggests it may have been deposited under similar circumstances.

  6. Terrain on Europa under Changing Lighting Conditions

    Science.gov (United States)

    1997-01-01

    These images obtained by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft show the same region of Europa under different lighting conditions. The upper image was obtained on June 28th, 1996 during Galileo's first orbit around Jupiter under 'high-sun' conditions -- the equivalent of taking a picture from a high altitude at noon (with the sun directly overhead). Note that albedo (light/dark) features are emphasized. Compare this to the lower image containing a higher-resolution inset. This (inset) image was taken on November 6th, 1996 during the spacecraft's third orbit under 'low-sun' illumination -- the equivalent of taking a picture from a high altitude at sunrise or sunset. Note that in this image the albedo features are not readily apparent. Instead, the topography of the terrain is emphasized. Planetary geologists use information from images acquired under a variety of lighting conditions to identify different types of structures and interpret how they formed. Note that the bright linear features in the upper image are seen to be ridges in the lower image. The circular feature on the right side of both images, Cilix, is approximately 25 kilometers (15 miles) across.The area seen in the upper image is 312 kilometers (187 miles) by 570 kilometers (342 miles) across; the area covered by the inset is 36 kilometers (22 miles) by 315 kilometers (190 miles) across. Both of these images are centered near 2 South latitude, 185 West longitude. North is to the top of the frames.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  7. Strain in Archean Granite-Greenstone terrains

    Science.gov (United States)

    Robin, C. M.; Bailey, R. C.

    2009-12-01

    A long-standing problem in Archean tectonics is the mode of origin of granite-greenstone belts. Based on structural and morphological similarities to salt domes and Rayleigh-Taylor structures, diapirism has long been an obvious but controversial candidate, as it implies the operation of vertical tectonics in the Archean. Current strain patterns are one of the few field observables available to test hypotheses about the kinematic history of granite-greenstone belts. Previous laboratory (Dixon & Summers, 1983) and numerical (Mareschal & West, 1980) experiments which have been used to predict strain in diapiric structures may not be realistic because of the lack of large thermally activated viscosity contrasts in these models. We have numerically modeled temperature-dependent, non-Newtonian visco-elastic solid-state diapirism under conditions appropriate to Archean crust (Robin & Bailey, 2009). Here we present analyses of strain derived from these models. Our results show important differences from those of previous modelers. These include the formation of narrow high strain zones in the greenstone at the batholith contact and in the axis of the keel, with a low-strain zone between the two, as well as only very small strains in the batholith itself. This suggests that strain recorded in the granitic domes of granite-greenstone terrains must be unrelated to the diapiric overturn mechanism. Our strain analyses should be useful for comparison with published and future field observations, and provide a basis for the interpretation of strain in these ubiquitous Archean structures. Principle strain directions for an evolved diapir resulting from an altered basaltic crust deposited over a granitic basement. Viscosities are temperature- and stress-dependent and viscoelastic.

  8. InSAR Terrain Mapping Using ICESat Laser Altimetry

    Science.gov (United States)

    Atwood, D.; Guritz, R.; Muskett, R.; Lingle, C.; Sauber, J.

    2006-12-01

    High quality geodetic ground control is time-consuming and costly to acquire in remote regions, where logistical operations are difficult to support. Hence, there is a strong interest in establishing new sources of ground control points that can be used in conjunction with Interferometric SAR (InSAR) for producing accurate digital elevation models (DEMs). In January 2003, NASA launched the Geoscience Laser Altimeter System (GLAS) into high polar orbit onboard the Ice, Cloud, and land Elevation Satellite (ICESat). A major objective of this spaceborne laser altimeter system, with orbital coverage extending from 86° N to 86° S, is to provide elevation measurements of the Earth's topography with unprecedented accuracy. The intent of our project is to assess the accuracy of ICESat elevation data and evaluate its utility as ground control for topographic mapping. Our study area lies near Barrow, Alaska; 15,650 sq. km of coastal plain adjacent to the Arctic Ocean, characterized by vast expanses of tundra, lakes, and arctic wetlands of such low relief as to be nearly devoid of terrain features. Accuracy of the ICESat elevation measurements is assessed through comparison with differential GPS (DGPS) data, acquired along ICESat ground tracks crossing our study area. Using DGPS as the reference, ICESat yields a mean offset of -0.04 ± 0.15 m for fast static measurements on frozen tundra lakes and 0.22 ± 0.96 m for two kinematic DGPS profiles along the ICESat ground track. These results suggests that ICESat-derived elevations on the Arctic coastal plain are more than sufficiently accurate for use as ground control in DEM generation. The only clear limitation of the ICESat data is the non-uniform distribution of the ICESat tracks within the 33 day near-repeat sub-cycle. Although the coverage is poor at equatorial latitudes, track separation in the Arctic is on the order of tens of kilometers because of orbital convergence at the Poles. To test whether these data can be used

  9. Integrated terrain mapping with digital Landsat images in Queensland, Australia

    Science.gov (United States)

    Robinove, Charles Joseph

    1979-01-01

    Mapping with Landsat images usually is done by selecting single types of features, such as soils, vegetation, or rocks, and creating visually interpreted or digitally classified maps of each feature. Individual maps can then be overlaid on or combined with other maps to characterize the terrain. Integrated terrain mapping combines several terrain features into each map unit which, in many cases, is more directly related to uses of the land and to methods of land management than the single features alone. Terrain brightness, as measured by the multispectral scanners in Landsat 1 and 2, represents an integration of reflectance from the terrain features within the scanner's instantaneous field of view and is therefore more correlatable with integrated terrain units than with differentiated ones, such as rocks, soils, and vegetation. A test of the feasibilty of the technique of mapping integrated terrain units was conducted in a part of southwestern Queensland, Australia, in cooperation with scientists of the Queensland Department of Primary Industries. The primary purpose was to test the use of digital classification techniques to create a 'land systems map' usable for grazing land management. A recently published map of 'land systems' in the area (made by aerial photograph interpretation and ground surveys), which are integrated terrain units composed of vegetation, soil, topography, and geomorphic features, was used as a basis for comparison with digitally classified Landsat multispectral images. The land systems, in turn, each have a specific grazing capacity for cattle (expressed in beasts per km 2 ) which is estimated following analysis of both research results and property carrying capacities. Landsat images, in computer-compatible tape form, were first contrast-stretched to increase their visual interpretability, and digitally classified by the parallelepiped method into distinct spectral classes to determine their correspondence to the land systems classes and

  10. Evaluation of topographic index in relation to terrain roughness and ...

    Indian Academy of Sciences (India)

    Journal of Earth System Science. Current Issue : Vol. 126, Issue 8 · Current Issue Volume 126 | Issue 8. December 2017. Home · Volumes & Issues · Special Issues · Forthcoming Articles · Search · Editorial Board · Information for Authors · Subscription ...

  11. Terrain controls on the occurrence of coastal retrogressive thaw slumps along the Yukon Coast, Canada

    Science.gov (United States)

    Ramage, Justine L.; Irrgang, Anna M.; Herzschuh, Ulrike; Morgenstern, Anne; Couture, Nicole; Lantuit, Hugues

    2017-09-01

    Retrogressive thaw slumps (RTSs) are among the most active landforms in the Arctic; their number has increased significantly over the past decades. While processes initiating discrete RTSs are well identified, the major terrain controls on the development of coastal RTSs at a regional scale are not yet defined. Our research reveals the main geomorphic factors that determine the development of RTSs along a 238 km segment of the Yukon Coast, Canada. We (1) show the current extent of RTSs, (2) ascertain the factors controlling their activity and initiation, and (3) explain the spatial differences in the density and areal coverage of RTSs. We mapped and classified 287 RTSs using high-resolution satellite images acquired in 2011. We highlighted the main terrain controls over their development using univariate regression trees model. Coastal geomorphology influenced both the activity and initiation of RTSs: active RTSs and RTSs initiated after 1972 occurred primarily on terrains with slope angles greater than 3.9° and 5.9°, respectively. The density and areal coverage of RTSs were constrained by the volume and thickness of massive ice bodies. Differences in rates of coastal change along the coast did not affect the model. We infer that rates of coastal change averaged over a 39 year period are unable to reflect the complex relationship between RTSs and coastline dynamics. We emphasize the need for large-scale studies of RTSs to evaluate their impact on the ecosystem and to measure their contribution to the global carbon budget.

  12. Multidimensional method-of-lines transport for atmospheric flows over steep terrain using arbitrary meshes

    Science.gov (United States)

    Shaw, James; Weller, Hilary; Methven, John; Davies, Terry

    2017-09-01

    Including terrain in atmospheric models gives rise to mesh distortions near the lower boundary that can degrade accuracy and challenge the stability of transport schemes. Multidimensional transport schemes avoid splitting errors on distorted, arbitrary meshes, and method-of-lines schemes have a low computational cost because they perform reconstructions at fixed points. This paper presents a multidimensional method-of-lines finite volume transport scheme, ;cubicFit;, which is designed to be numerically stable on arbitrary meshes. Stability conditions derived from a von Neumann stability analysis are imposed during model initialisation to obtain stability and improve accuracy in distorted regions of the mesh, and near steeply-sloping lower boundaries. Reconstruction calculations depend upon the mesh only, needing just one vector multiply per face per time-stage irrespective of the velocity field. The cubicFit scheme is evaluated using three, idealised numerical tests. The first is a variant of a standard horizontal transport test on severely distorted terrain-following meshes. The second is a new test case that assesses accuracy near the ground by transporting a tracer at the lower boundary over steep terrain on terrain-following meshes, cut-cell meshes, and new, slanted-cell meshes that do not suffer from severe time-step constraints associated with cut cells. The third, standard test deforms a tracer in a vortical flow on hexagonal-icosahedral meshes and cubed-sphere meshes. In all tests, cubicFit is stable and largely insensitive to mesh distortions, and cubicFit results are more accurate than those obtained using a multidimensional linear upwind transport scheme. The cubicFit scheme is second-order convergent regardless of mesh distortions.

  13. On autonomous terrain model acquistion by a mobile robot

    Science.gov (United States)

    Rao, N. S. V.; Iyengar, S. S.; Weisbin, C. R.

    1987-01-01

    The following problem is considered: A point robot is placed in a terrain populated by an unknown number of polyhedral obstacles of varied sizes and locations in two/three dimensions. The robot is equipped with a sensor capable of detecting all the obstacle vertices and edges that are visible from the present location of the robot. The robot is required to autonomously navigate and build the complete terrain model using the sensor information. It is established that the necessary number of scanning operations needed for complete terrain model acquisition by any algorithm that is based on scan from vertices strategy is given by the summation of i = 1 (sup n) N(O sub i)-n and summation of i = 1 (sup n) N(O sub i)-2n in two- and three-dimensional terrains respectively, where O = (O sub 1, O sub 2,....O sub n) set of the obstacles in the terrain, and N(O sub i) is the number of vertices of the obstacle O sub i.

  14. The Improved Kriging Interpolation Algorithm for Local Underwater Terrain Based on Fractal Compensation

    Directory of Open Access Journals (Sweden)

    Pengyun Chen

    2014-01-01

    Full Text Available The interpolation-reconstruction of local underwater terrain using the underwater digital terrain map (UDTM is an important step for building an underwater terrain matching unit and directly affects the accuracy of underwater terrain matching navigation. The Kriging method is often used in terrain interpolation, but, with this method, the local terrain features are often lost. Therefore, the accuracy cannot meet the requirements of practical application. Analysis of the geographical features is performed on the basis of the randomness and self-similarity of underwater terrain. We extract the fractal features of local underwater terrain with the fractal Brownian motion model, compensating for the possible errors of the Kriging method with fractal theory. We then put forward an improved Kriging interpolation method based on this fractal compensation. Interpolation-reconstruction tests show that the method can simulate the real underwater terrain features well and that it has good usability.

  15. Introduction Wind farms in complex terrains: an introduction.

    Science.gov (United States)

    Alfredsson, P H; Segalini, A

    2017-04-13

    Wind energy is one of the fastest growing sources of sustainable energy production. As more wind turbines are coming into operation, the best locations are already becoming occupied by turbines, and wind-farm developers have to look for new and still available areas-locations that may not be ideal such as complex terrain landscapes. In these locations, turbulence and wind shear are higher, and in general wind conditions are harder to predict. Also, the modelling of the wakes behind the turbines is more complicated, which makes energy-yield estimates more uncertain than under ideal conditions. This theme issue includes 10 research papers devoted to various fluid-mechanics aspects of using wind energy in complex terrains and illustrates recent progress and future developments in this important field.This article is part of the themed issue 'Wind energy in complex terrains'. © 2017 The Author(s).

  16. ISOSTATICALLY DISTURBED TERRAIN OF NORTHWESTERN ANDES MOUNTAINS FROM SPECTRALLY CORRELATED FREE-AIR AND GRAVITY TERRAIN DATA

    Directory of Open Access Journals (Sweden)

    Hernández P Orlando

    2006-12-01

    Full Text Available Recently revised models on global tectonics describe the convergence of the North Andes, Nazca, Caribbean and South American Plates and their seismicity, volcanism, active faulting and extreme
    topography. The current plate boundaries of the area are mainly interpreted from volcanic and seismic datasets with variable confidence levels. New insights on the isostatic state and plate boundaries of
    the northwestern Andes Mountains can be obtained from the spectral analysis of recently available gravity and topography data.
    Isostatically disturbed terrain produces free-air anomalies that are highly correlated with the gravity effects of the terrain. The terrain gravity effects (TGE and free air gravity anomalies (FAGA of the
    Andes mountains spectral correlation data confirms that these mountains are isostatically disturbed. Strong negative terrain-correlated FAGA along western South America and the Greater and Lesser Antilles are consistent with anomalously deepened mantle displaced by subducting oceanic plates.

    Inversion of the compensated terrain gravity effects (CTGE reveals plate subduction systems with alternating shallower and steeper subduction angles. The gravity modeling highlights crustal
    deformation from plate collision and subduction and other constraints on the tectonism of the plate boundary zones for the region.

  17. Exact and approximate computations of watersheds on triangulated terrains

    DEFF Research Database (Denmark)

    Tsirogiannis, Konstantinos; de Berg, Mark

    2011-01-01

    The natural way of modeling water flow on a triangulated terrain is to make the fundamental assumption that water follows the direction of steepest descent (dsd). However, computing watersheds and other flow-related structures according to the dsd model in an exact manner is difficult: the dsd...... implementation that computes watersheds on triangulated terrains following strictly the dsd model and using exact arithmetic, and we experimentally investigate its computational cost. Our experiments show that the algorithm cannot handle large data sets effectively, due to the bit-sizes needed in the exact...

  18. Terrain Quantization Model Based on Global Subdivision Grid

    Directory of Open Access Journals (Sweden)

    MENG Li

    2016-12-01

    Full Text Available To solve the current problems in terrain quantization, such as the limitation of grid levels, the difficulties in data organization and management, and other issues, a quadrilateral terrain quantization model based on global subdivision grid is proposed. The model adopts GeoSOT as the spatial reference, and realize the correlation and retrieval of quantization data among different layers based on GeoSOT location identification code, which provides methods of the the quantization procession, the organization and storage, the data aggregation of the vector data and regular grid data.

  19. Hexographic Method of Complex Town-Planning Terrain Estimate

    Science.gov (United States)

    Khudyakov, A. Ju

    2017-11-01

    The article deals with the vital problem of a complex town-planning analysis based on the “hexographic” graphic analytic method, makes a comparison with conventional terrain estimate methods and contains the method application examples. It discloses a procedure of the author’s estimate of restrictions and building of a mathematical model which reflects not only conventional town-planning restrictions, but also social and aesthetic aspects of the analyzed territory. The method allows one to quickly get an idea of the territory potential. It is possible to use an unlimited number of estimated factors. The method can be used for the integrated assessment of urban areas. In addition, it is possible to use the methods of preliminary evaluation of the territory commercial attractiveness in the preparation of investment projects. The technique application results in simple informative graphics. Graphical interpretation is straightforward from the experts. A definite advantage is the free perception of the subject results as they are not prepared professionally. Thus, it is possible to build a dialogue between professionals and the public on a new level allowing to take into account the interests of various parties. At the moment, the method is used as a tool for the preparation of integrated urban development projects at the Department of Architecture in Federal State Autonomous Educational Institution of Higher Education “South Ural State University (National Research University)”, FSAEIHE SUSU (NRU). The methodology is included in a course of lectures as the material on architectural and urban design for architecture students. The same methodology was successfully tested in the preparation of business strategies for the development of some territories in the Chelyabinsk region. This publication is the first in a series of planned activities developing and describing the methodology of hexographical analysis in urban and architectural practice. It is also

  20. CONTEXT-BASED URBAN TERRAIN RECONSTRUCTION FROM IMAGES AND VIDEOS

    Directory of Open Access Journals (Sweden)

    D. Bulatov

    2012-07-01

    Full Text Available Detection of buildings and vegetation, and even more reconstruction of urban terrain from sequences of aerial images and videos is known to be a challenging task. It has been established that those methods that have as input a high-quality Digital Surface Model (DSM, are more straight-forward and produce more robust and reliable results than those image-based methods that require matching line segments or even whole regions. This motivated us to develop a new dense matching technique for DSM generation that is capable of simultaneous integration of multiple images in the reconstruction process. The DSMs generated by this new multi-image matching technique can be used for urban object extraction. In the first contribution of this paper, two examples of external sources of information added to the reconstruction pipeline will be shown. The GIS layers are used for recognition of streets and suppressing false alarms in the depth maps that were caused by moving vehicles while the near infrared channel is applied for separating vegetation from buildings. Three examples of data sets including both UAV-borne video sequences with a relatively high number of frames and high-resolution (10 cm ground sample distance data sets consisting of (few spatial-temporarily diverse images from large-format aerial frame cameras, will be presented. By an extensive quantitative evaluation of the Vaihingen block from the ISPRS benchmark on urban object detection, it will become clear that our procedure allows a straight-forward, efficient, and reliable instantiation of 3D city models.

  1. Analysis of terrains suitable for tourism and recreation by using geographic information system (GIS).

    Science.gov (United States)

    Aklıbaşında, Meliha; Bulut, Yahya

    2014-09-01

    The use and utilization areas of geographic information system (GIS) increase every day due to both enabling easiness in storing, updating, grouping, analyzing, correlating, and mapping of data about evaluation factors in planning studies and having quite low error margin depending on the accuracy of data stored. In fact, GIS is also used both in visualization and in various analyses in planning tourism terrains. In this study, the effectiveness of GIS on holistic evaluation of natural and cultural resources in planning tourism terrains was analyzed. Natural and cultural resources in Kayseri Yahyalı were quantified by using ArcGIS 9.3 software from GIS software; data were analyzed and potential tourism and recreation terrains, level of suitability, and rate of coverage were determined. As a result of the analyses, it was determined that 11.847 ha area (6,53%) was quite suitable for such kind of activities, 103.010 ha (56,77%) was suitable, 39.278 ha (21,65%) was less suitable, and 27.314 ha area (15,05%) was not suitable. In the next stage, landscape properties which are suitable for tourism and recreation were evaluated and landscape types were classified in the sense of their tourist attraction. It was determined that the water resources and valley landscapes were the basic sources of the tourism and recreation activities of Yahyalı, and it was determined that the landscape of the forest and mountain was important for variety of the tourism and recreation activities of Yahyalı.

  2. Generating a model of the terrain in the aspect of flood risk estimation

    Directory of Open Access Journals (Sweden)

    Andrzej Kwinta

    2014-12-01

    Full Text Available Flood modeling is carried out based on the Digital Terrain Model (DTM and hydrological data. The quality of the input data for modeling determines the reliability of flood risk assessment. The accuracy of the DTM is affected by the method of data acquisition and mathematical modeling errors. This paper presents a method for evaluating the impact of the accuracy of measurement and modeling based on the DTM. The analysis was performed on a hypothetical example generated by statistical methods. This method can be used to analyze various aspects of precision in creating DTMs.

  3. Simulating Sand Behavior through Terrain Subdivision and Particle Refinement

    Science.gov (United States)

    Clothier, M.

    2013-12-01

    Advances in computer graphics, GPUs, and parallel processing hardware have provided researchers with new methods to visualize scientific data. In fact, these advances have spurred new research opportunities between computer graphics and other disciplines, such as Earth sciences. Through collaboration, Earth and planetary scientists have benefited by using these advances in hardware technology to process large amounts of data for visualization and analysis. At Oregon State University, we are collaborating with the Oregon Space Grant and IGERT Ecosystem Informatics programs to investigate techniques for simulating the behavior of sand. In addition, we have also been collaborating with the Jet Propulsion Laboratory's DARTS Lab to exchange ideas on our research. The DARTS Lab specializes in the simulation of planetary vehicles, such as the Mars rovers. One aspect of their work is testing these vehicles in a virtual "sand box" to test their performance in different environments. Our research builds upon this idea to create a sand simulation framework to allow for more complex and diverse environments. As a basis for our framework, we have focused on planetary environments, such as the harsh, sandy regions on Mars. To evaluate our framework, we have used simulated planetary vehicles, such as a rover, to gain insight into the performance and interaction between the surface sand and the vehicle. Unfortunately, simulating the vast number of individual sand particles and their interaction with each other has been a computationally complex problem in the past. However, through the use of high-performance computing, we have developed a technique to subdivide physically active terrain regions across a large landscape. To achieve this, we only subdivide terrain regions where sand particles are actively participating with another object or force, such as a rover wheel. This is similar to a Level of Detail (LOD) technique, except that the density of subdivisions are determined by

  4. Integrating land cover and terrain characteristics to explain plague ...

    African Journals Online (AJOL)

    Boosted Regression Tree (BRT) statistical method was used to clarify the relationships between land cover and terrain variables with small mammals and fleas. Results indicate that elevation positively influenced the presence of small mammals. The presence of fleas was clearly influenced by land management features ...

  5. Scalable Algorithms for Large High-Resolution Terrain Data

    DEFF Research Database (Denmark)

    Mølhave, Thomas; Agarwal, Pankaj K.; Arge, Lars Allan

    2010-01-01

    In this paper we demonstrate that the technology required to perform typical GIS computations on very large high-resolution terrain models has matured enough to be ready for use by practitioners. We also demonstrate the impact that high-resolution data has on common problems. To our knowledge, so...

  6. Mountain Biking: Does Rough Terrain Make Rugged Riders?

    Science.gov (United States)

    Cinque, Chris

    1987-01-01

    No formal research has been conducted on the training effects and injury risks of all-terrain bicycles in mountain biking, but experience indicates they are apparently safe and may provide greater fitness benefits than traditional bicycles. The bicycles are described, and their apparent benefits are discussed. (MT)

  7. Modeling Air-Quality in Complex Terrain Using Mesoscale and ...

    African Journals Online (AJOL)

    Air-quality in a complex terrain (Colorado-River-Valley/Grand-Canyon Area, Southwest U.S.) is modeled using a higher-order closure mesoscale model and a higher-order closure dispersion model. Non-reactive tracers have been released in the Colorado-River valley, during winter and summer 1992, to study the ...

  8. Terrain Mapping and Obstacle Detection Using Gaussian Processes

    DEFF Research Database (Denmark)

    Kjærgaard, Morten; Massaro, Alessandro Salvatore; Bayramoglu, Enis

    2011-01-01

    In this paper we consider a probabilistic method for extracting terrain maps from a scene and use the information to detect potential navigation obstacles within it. The method uses Gaussian process regression (GPR) to predict an estimate function and its relative uncertainty. To test the new met...

  9. Terrain Mapping and Obstacle Detection using Gaussian Processes

    DEFF Research Database (Denmark)

    Kjærgaard, Morten; Massaro, Alessandro Salvatore; Bayramoglu, Enis

    2011-01-01

    In this paper we consider a probabilistic method for extracting terrain maps from a scene and use the information to detect potential navigation obstacles within it. The method uses Gaussian process regression (GPR) to predict an estimate function and its relative uncertainty. To test the new met...

  10. The retrieval of land surface albedo in rugged terrain

    NARCIS (Netherlands)

    Gao, B.; Jia, L.; Menenti, M.

    2012-01-01

    Land surface albedo may be derived from the satellite data through the estimation of a bidirectional reflectance distribution function (BRDF) model and angular integration. However many BRDF models do not consider explicitly the topography. In rugged terrain, the topography influences the observed

  11. How fine is fine enough when doing CFD terrain simulations

    DEFF Research Database (Denmark)

    Sørensen, Niels N.; Bechmann, Andreas; Réthoré, Pierre-Elouan

    The present work addresses the problem of establishing the necessary grid resolution to obtain a given level of numerical accuracy using a CFD model for prediction of flow over terrain. It is illustrated, that a very high resolution may be needed if the numerical difference between consecutive...

  12. How fine is fine enough when doing CFD terrain simulations

    DEFF Research Database (Denmark)

    Sørensen, Niels N.; Bechmann, Andreas; Réthoré, Pierre-Elouan

    2012-01-01

    The present work addresses the problemof establishing the necessary grid resolution to obtain a given level of numerical accuracy using a CFD model for prediction of flow over terrain. It is illustrated, that a very high resolution may be needed if the numerical difference between consecutive...

  13. Simulation of Wind Farms in Flat & Complex terrain using CFD

    DEFF Research Database (Denmark)

    Prospathopoulos, John; Cabezon, D.; Politis, E.S.

    2010-01-01

    Use of computational fluid dynamic (CFD) methods to predict the power production from wind entire wind farms in flat and complex terrain is presented in this paper. Two full 3D Navier–Stokes solvers for incompressible flow are employed that incorporate the k–ε and k–ω turbulence models respectively...

  14. Prediction of wind energy distribution in complex terrain using CFD

    DEFF Research Database (Denmark)

    Xu, Chang; Li, Chenqi; Yang, Jianchuan

    2013-01-01

    Based on linear models, WAsP software predicts wind energy distribution, with a good accuracy for flat terrain, but with a large error under complicated topography. In this paper, numerical simulations are carried out using the FLUENT software on a mesh generated by the GAMBIT and ARGIS software...

  15. Shape-assisted body reorientation enhances trafficability through cluttered terrain

    Science.gov (United States)

    Li, Chen; Pullin, Andrew; Haldane, Duncan; Fearing, Ronald; Full, Robert

    2014-11-01

    Many birds and fishes have slender, streamlined bodies that reduce fluid dynamic drag and allow fast and efficient locomotion. Similarly, numerous terrestrial animals run through cluttered terrain where 3-D, multi-component obstacles like grass, bushes, trees, walls, doors, and pillars also resist motion, but it is unknown whether their body shape plays a major role. Here, we challenged discoid cockroaches that possess a rounded, thin, nearly ellipsoidal body to run through tall, narrowly spaced, grass-like beams. The animals primarily rolled their body to the side to maneuver through the obstacle gaps. Reduction of body roundness by artificial shells inhibited this side roll maneuver, resulting in a lower traversal probability and a longer traversal time (P robot of a nearly cuboidal body. The rounded shell enabled the robot to use passive side rolling to maneuver through beams. To explain the mechanism, we developed a simple physics model to construct an energy landscape of the body-terrain interaction, which allowed estimation of body forces and torques exerted by the beams. Our model revealed that, by passive interaction with the terrain, a rounded body (ellipsoid) rolled more easily than an angular body (cuboid) to access energy valleys between energy barriers caused by obstacles. Our study is the first to demonstrate that a terradynamically ``streamlined'' shape can reduce terrain resistance and enhance trafficability by assisting body reorientation.

  16. Hydrogeophysical study of parts of charnockite terrain of Akure ...

    African Journals Online (AJOL)

    Hydrogeophysical study of parts of Charnockite terrain of Akure, southwestern Nigeria was carried out using the electrical resistivity method. The study involved one hundred and fifty two (152) Schlumberger geoelectric soundings (with seven (7) of them parametric)) alongside static water level measurements in 102 ...

  17. Prediction of characteristics of coastal plain soils using terrain ...

    African Journals Online (AJOL)

    Soil properties determined include depth, sand, silt, clay, electrical and hydraulic conductivity, bulk density, pH, exchangeable calcium, magnesium, sodium, potassium and acidity, available phosphorus, organic carbon, base saturation, crystalline and amorphous iron and aluminium oxides. The terrain attributes derived ...

  18. Effect of terrains on the volatiles of Cabernet Sauvignon wines ...

    African Journals Online (AJOL)

    These odorants are associated with “fruity'' and ''ripe fruit'' odor descriptors. Wine from flat land with higher OAVs of ethyl octanoate and isoamyl acetate seems to have more intense fruity aromas (pineapple, pear and banana), with floral notes. Keywords: Cabernet Sauvignon wines, volatiles, terrains, Loess Plateau region, ...

  19. Effect of terrains on the volatiles of Cabernet Sauvignon wines ...

    African Journals Online (AJOL)

    user

    2012-04-24

    Apr 24, 2012 ... from flat land with higher OAVs of ethyl octanoate and isoamyl acetate seems to have more intense fruity aromas (pineapple, pear and banana), with floral notes. Key words: Cabernet Sauvignon wines, volatiles, terrains, Loess Plateau region, headspace solid phase microextraction (HS-SPME), gas ...

  20. Planning Routes Across Economic Terrains: Maximizing Utility, Following Heuristics

    Science.gov (United States)

    Zhang, Hang; Maddula, Soumya V.; Maloney, Laurence T.

    2010-01-01

    We designed an economic task to investigate human planning of routes in landscapes where travel in different kinds of terrain incurs different costs. Participants moved their finger across a touch screen from a starting point to a destination. The screen was divided into distinct kinds of terrain and travel within each kind of terrain imposed a cost proportional to distance traveled. We varied costs and spatial configurations of terrains and participants received fixed bonuses minus the total cost of the routes they chose. We first compared performance to a model maximizing gain. All but one of 12 participants failed to adopt least-cost routes and their failure to do so reduced their winnings by about 30% (median value). We tested in detail whether participants’ choices of routes satisfied three necessary conditions (heuristics) for a route to maximize gain. We report failures of one heuristic for 7 out of 12 participants. Last of all, we modeled human performance with the assumption that participants assign subjective utilities to costs and maximize utility. For 7 out 12 participants, the fitted utility function was an accelerating power function of actual cost and for the remaining 5, a decelerating power function. We discuss connections between utility aggregation in route planning and decision under risk. Our task could be adapted to investigate human strategy and optimality of route planning in full-scale landscapes. PMID:21833269

  1. CALCULATION OF CHEMICAL ATMOSPHERE ESTIMATION GIVEN THE COMPLEX TERRAIN

    Directory of Open Access Journals (Sweden)

    M. M. Biliaiev

    2010-06-01

    Full Text Available The 3D numerical model was used to simulate the toxic gas dispersion over a complex terrain after an accident spillage. The model is based on the K-gradient transport model and the model of potential flow. The results of numerical experiment are presented.

  2. Group Dynamics and Decision Making: Backcountry Recreationists in Avalanche Terrain

    Science.gov (United States)

    Bright, Leslie Shay

    2010-01-01

    The purpose of this study was to describe and determine the prevalence of decision-making characteristics of recreational backcountry groups when making a decision of where to travel and ride in avalanche terrain from the perspective of individuals. Decision-making characteristics encompassed communication, decision-making processes, leadership,…

  3. Effects of All-Terrain Vehicles on Stream Dynamics

    Science.gov (United States)

    Anne Chin; Deven M. Rohrer; Daniel A. Marion; J. Alan Clingenpeel

    2004-01-01

    Abstract - This paper reports preliminary results from research conducted in the Ouachita National Forest to assess the effects of all-terrain vehicle (ATV) trails on stream characteristics. The study focuses on the Wolf Pen Gap Trail that has been in use since 1991. We examine whether that the trail system has caused increased sediment input to and...

  4. Terrain And Laboratory Conductivity Studies Of Flood Plains Of ...

    African Journals Online (AJOL)

    A shallow electromagnetic study (electrical conductivity and magnetic susceptibility measurements) and laboratory conductivity sampling of the flood plains of Oluwatuyi/Oshinle area of Akure have been undertaken. This is with the aim of correlating the terrain conductivity mapping with laboratory measurements to establish ...

  5. Representations and Metrics for Time-Varying Terrain Surfaces

    Science.gov (United States)

    2013-08-06

    simpler computational models, such as deterministic finite automata , for which computational equivalence is computable that we are also investigating...Surge ............................................................... 10 3.3 Application of Interactive Mesh Differencing Tool...terrain analysis applications of the uncertainty band around the ridge surface The surface and volume structure will both be multi-resolution and

  6. Sculpting Mountains: Interactive Terrain Modeling Based on Subsurface Geology.

    Science.gov (United States)

    Cordonnier, Guillaume; Cani, Marie-Paule; Benes, Bedrich; Braun, Jean; Galin, Eric

    2017-03-29

    Most mountain ranges are formed by the compression and folding of colliding tectonic plates. Subduction of one plate causes large-scale asymmetry while their layered composition (or stratigraphy) explains the multi-scale folded strata observed on real terrains. We introduce a novel interactive modeling technique to generate visually plausible, large scale terrains that capture these phenomena. Our method draws on both geological knowledge for consistency and on sculpting systems for user interaction. The user is provided hands-on control on the shape and motion of tectonic plates, represented using a new geologically-inspired model for the Earth crust. The model captures their volume preserving and complex folding behaviors under collision, causing mountains to grow. It generates a volumetric uplift map representing the growth rate of subsurface layers. Erosion and uplift movement are jointly simulated to generate the terrain. The stratigraphy allows us to render folded strata on eroded cliffs. We validated the usability of our sculpting interface through a user study, and compare the visual consistency of the earth crust model with geological simulation results and real terrains.

  7. Flow and wakes in complex terrain and offshore

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca J.; Schepers, J.G.; Pihl, Sander van der

    2007-01-01

    The paper presents research conducted in the Flow workpackage of the EU funded UPWIND project which focuses on improving models for flow within and downwind of large wind farms in complex terrain and offshore. The main activity is modelling the behaviour of wind turbine wakes in order to improve ...

  8. Interactive Editing of GigaSample Terrain Fields

    KAUST Repository

    Treib, Marc

    2012-05-01

    Previous terrain rendering approaches have addressed the aspect of data compression and fast decoding for rendering, but applications where the terrain is repeatedly modified and needs to be buffered on disk have not been considered so far. Such applications require both decoding and encoding to be faster than disk transfer. We present a novel approach for editing gigasample terrain fields at interactive rates and high quality. To achieve high decoding and encoding throughput, we employ a compression scheme for height and pixel maps based on a sparse wavelet representation. On recent GPUs it can encode and decode up to 270 and 730 MPix/s of color data, respectively, at compression rates and quality superior to JPEG, and it achieves more than twice these rates for lossless height field compression. The construction and rendering of a height field triangulation is avoided by using GPU ray-casting directly on the regular grid underlying the compression scheme. We show the efficiency of our method for interactive editing and continuous level-of-detail rendering of terrain fields comprised of several hundreds of gigasamples. © 2012 The Author(s).

  9. Crustal Structure around Ordos Terrain Derived from Ambient Noise Tomography

    Science.gov (United States)

    Liu, J.; Ning, J.; Tang, Y.; Chen, Y. J.

    2011-12-01

    We performed Rayleigh wave tomography around Ordos terrain by applying the ambient noise method to broadband seismic data. The data was recorded at 85 temporary stations of PKU array operated along Yinchuan-Jinan and 410 permanent stations of CEA network operated between Eastern margin of Tibetan plateau and Huabei basin. Receiver function technique was also applied to study Moho discontinuity in Southern Ordos by PKU array. We developed a new stacking technique to obtain high-quality dispersion curves of Rayleigh waves from cross correlation of seismic ambient noise. This technique is based on phase-matched filter and was implemented in a four-step iterative process: signal compression, stacking, signal extraction and signal decompression. We stack all the compressed Estimated Green Functions that have almost the same path to improve signal to noise ratio. Results show that this new stacking method is stable and can improve the quality of ambient noise inversion. The inversion results present in this study are consistent with tectonic nature in this region. S velocity at depths of 0-10 km beneath Huabei plain, Sichuan basin and Ordos terrain are obviously lower than those beneath Eastern margin of Tibetan plateau. That is probably due to the thick sediments in Huabei plain, Sichuan basin and Ordos block. S velocity beneath Lvliang-Taihang region keeps high in whole crust and this may relate to Cenozoic intrusion of mantle material here. Our results revealed that the crust is thick in the southern part of the Ordos terrain while it is a little thin in the northern part. This confirmed the result given by Chen et al. (2010) and explained the contradiction between the work of Chen's and former results. The contrasting crustal thickness of the Ordos terrain is also in accord with our Receiver Function results. Receiver functions revealed two interfaces at about 40 km and 60 km in southern part of the Ordos terrain, comparing with only one located at about 40 km depth

  10. Flight-appropriate 3D Terrain-rendering Toolkit for Synthetic Vision Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The TerraBlocksTM 3D terrain data format and terrain-block-rendering methodology provides an enabling basis for successful commercial deployment of...

  11. Autonomous terrain characterization and modelling for dynamic control of unmanned vehicles

    Science.gov (United States)

    Talukder, A.; Manduchi, R.; Castano, R.; Owens, K.; Matthies, L.; Castano, A.; Hogg, R.

    2002-01-01

    This end-to-end obstacle negotiation system is envisioned to be useful in optimized path planning and vehicle navigation in terrain conditions cluttered with vegetation, bushes, rocks, etc. Results on natural terrain with various natural materials are presented.

  12. Analyzing complex wake-terrain interactions and its implications on wind-farm performance.

    Science.gov (United States)

    Tabib, Mandar; Rasheed, Adil; Fuchs, Franz

    2016-09-01

    Rotating wind turbine blades generate complex wakes involving vortices (helical tip-vortex, root-vortex etc.).These wakes are regions of high velocity deficits and high turbulence intensities and they tend to degrade the performance of down-stream turbines. Hence, a conservative inter-turbine distance of up-to 10 times turbine diameter (10D) is sometimes used in wind-farm layout (particularly in cases of flat terrain). This ensures that wake-effects will not reduce the overall wind-farm performance, but this leads to larger land footprint for establishing a wind-farm. In-case of complex-terrain, within a short distance (say 10D) itself, the nearby terrain can rise in altitude and be high enough to influence the wake dynamics. This wake-terrain interaction can happen either (a) indirectly, through an interaction of wake (both near tip vortex and far wake large-scale vortex) with terrain induced turbulence (especially, smaller eddies generated by small ridges within the terrain) or (b) directly, by obstructing the wake-region partially or fully in its flow-path. Hence, enhanced understanding of wake- development due to wake-terrain interaction will help in wind farm design. To this end the current study involves: (1) understanding the numerics for successful simulation of vortices, (2) understanding fundamental vortex-terrain interaction mechanism through studies devoted to interaction of a single vortex with different terrains, (3) relating influence of vortex-terrain interactions to performance of a wind-farm by studying a multi-turbine wind-farm layout under different terrains. The results on interaction of terrain and vortex has shown a much faster decay of vortex for complex terrain compared to a flatter-terrain. The potential reasons identified explaining the observation are (a) formation of secondary vortices in flow and its interaction with the primary vortex and (b) enhanced vorticity diffusion due to increased terrain-induced turbulence. The implications of

  13. Impact of terrain attributes, parent material and soil types on gully erosion

    Science.gov (United States)

    Chaplot, Vincent

    2013-03-01

    Gully erosion is a worldwide matter of concern because of the irreversible losses of fertile land, which often have severe environmental, economic and social consequences. While most of the studies on the gullying process have investigated the involved mechanisms (either overland flow incision, seepage or piping erosion), only few have been conducted on the controlling factors of gully wall retreat, an important, if not the dominant, land degradation process and sediment source in river systems. In a representative 4.4 km2 degraded area of the Drakensberg foothills (South Africa) the main objective of this study was to evaluate the relationship between the rate of gully bank retreat (GBR) and parent material, soil types and selected terrain attributes (elevation, specific drainage area, mean slope gradient, slope length factor, stream power index, compound topographic index and slope curvatures). The survey of gully bank retreat was performed during an entire hydrological year, from September 2007 to September 2008, using a network of pins (n = 440 from 110 pits). Both the gully contours and pin coordinates were determined, using a GPS with a 0.5 m horizontal accuracy (n = 20,120). The information on the parent material and the soil types was obtained from field observations complemented by laboratory analysis, while terrain attributes were extracted from a 20 m DEM generated from 5 m interval contour lines. The average GBR value for the 6512 m of gully banks found in the area was 0.049 ± 0.0013 m y- 1, which, considering bank height and soil bulk density, corresponded to an erosion rate of 2.30 ton ha- 1 y- 1. There was no significant difference in GBR between sandstone and dolerite and between Acrisols and Luvisols. Despite a weak one-to-one correlation with the selected terrain attributes (r factors of control of GBR could help to address.

  14. Using game engine for 3D terrain visualisation of GIS data: A review

    Science.gov (United States)

    Che Mat, Ruzinoor; Shariff, Abdul Rashid Mohammed; Nasir Zulkifli, Abdul; Shafry Mohd Rahim, Mohd; Hafiz Mahayudin, Mohd

    2014-06-01

    This paper reviews on the 3D terrain visualisation of GIS data using game engines that are available in the market as well as open source. 3D terrain visualisation is a technique used to visualise terrain information from GIS data such as a digital elevation model (DEM), triangular irregular network (TIN) and contour. Much research has been conducted to transform the 2D view of map to 3D. There are several terrain visualisation softwares that are available for free, which include Cesium, Hftool and Landserf. This review paper will help interested users to better understand the current state of art in 3D terrain visualisation of GIS data using game engines.

  15. Comparing English, Mandarin, and Russian Hydrographic and Terrain Categories

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Chen-Chieh [National University of Singapore; Sorokine, Alexandre [ORNL

    2013-01-01

    The paper compares hydrographic and terrain categories in the geospatial data standards of the US, Taiwan, and Russian Federation where the dominant languages used are from di erent language families. It aims to identify structural and semantic di erences between similar categories across three geospatial data standards. By formalizing the data standard structures and identifying the properties that di erentiate sibling categories in each geospatial data standard using well-known formal relations and quality universals, we develop a common basis on which hydrographic and terrain categories in the three data standards can be compared. The result suggests that all three data standards structure categories with a mixture of relations with di erent meaning even though most of them are well-known relations in top-level ontologies. Similar categories can be found across all three standards but exact match between similar categories are rare.

  16. Quantifying Traversability of Terrain for a Mobile Robot

    Science.gov (United States)

    Howard, Ayanna; Seraji, Homayoun; Werger, Barry

    2005-01-01

    A document presents an updated discussion on a method of autonomous navigation for a robotic vehicle navigating across rough terrain. The method involves, among other things, the use of a measure of traversability, denoted the fuzzy traversability index, which embodies the information about the slope and roughness of terrain obtained from analysis of images acquired by cameras mounted on the robot. The improvements presented in the report focus on the use of the fuzzy traversability index to generate a traversability map and a grid map for planning the safest path for the robot. Once grid traversability values have been computed, they are utilized for rejecting unsafe path segments and for computing a traversalcost function for ranking candidate paths, selected by a search algorithm, from a specified initial position to a specified final position. The output of the algorithm is a set of waypoints designating a path having a minimal-traversal cost.

  17. Terrain, expérimentation et sciences sociales

    OpenAIRE

    Fleury-Vilatte, Béatrice; Walter, Jacques

    2013-01-01

    Consacrés au terrain et à la méthode expérimentale, ces « Échanges » donnent la parole à cinq chercheurs appartenant à différentes disciplines. C’est du côté de la mythologie que Stéphane Olivesi place le terrain dès lors qu’il en situe les usages et légitimations dans le champ académique. Pour sa part, Thierry Meyer mène une réflexion sur la validité externe des approches expérimentales. Françoise Bernard et Robert-Vincent Joule discutent de l’intérêt à intégrer une méthodologie d’inspiratio...

  18. Hierarchical stochastic model of terrain subsidence during tunnel excavation

    Science.gov (United States)

    Janda, Tomáš; Šejnoha, Jiří; Šejnoha, Michal

    2017-09-01

    In this contribution the Bayesian statistical method is applied to assess the expected probability distribution of the terrain subsidence in the course of tunnel excavation. The approach utilizes a number of simplifying assumptions regarding the system kinematics to arrive at a very simple model with just a few degrees of freedom. This deterministic model together with the intrinsic uncertainties of its parameters and measurement inaccuracies are used to formulate the stochastic model which defines a distribution of the predicted values of terrain subsidence. Assuming the measured data to be fixed, the stochastic model thus defines the likelihood function of the model parameters which is directly used for updating their prior distribution. This way the model parameters can be incrementally updated with each excavation step and the prediction of the model refined.

  19. Introduction Wind farms in complex terrains: an introduction

    Science.gov (United States)

    Alfredsson, P. H.; Segalini, A.

    2017-01-01

    Wind energy is one of the fastest growing sources of sustainable energy production. As more wind turbines are coming into operation, the best locations are already becoming occupied by turbines, and wind-farm developers have to look for new and still available areas—locations that may not be ideal such as complex terrain landscapes. In these locations, turbulence and wind shear are higher, and in general wind conditions are harder to predict. Also, the modelling of the wakes behind the turbines is more complicated, which makes energy-yield estimates more uncertain than under ideal conditions. This theme issue includes 10 research papers devoted to various fluid-mechanics aspects of using wind energy in complex terrains and illustrates recent progress and future developments in this important field. This article is part of the themed issue ‘Wind energy in complex terrains’. PMID:28265020

  20. Optimization of Wind Farm Layout in Complex Terrain

    DEFF Research Database (Denmark)

    Xu, Chang; Yang, Jianchuan; Li, Chenqi

    2013-01-01

    Microscopic site selection for wind farms in complex terrain is a technological difficulty in the development of onshore wind farms. This paper presented a method for optimizing wind farm layout in complex terrain. This method employed Lissaman and Jensen wake models, took wind velocity....... To calculate the output of each section, we used the wind speed distribution and its probability density as well as the wake loss between wind turbines for every section. The objective function is maximization of the whole wind farm's power output and the free variables are the wind turbines' coordinates which...... distribution law and wake loss between different turbines into consideration and calculated the sheltering area effect of wake loss from upstream wind turbines on downstream wind turbines. Wind direction was divided into sixteen sections, and the wind speed was processed by the Weibull distribution...

  1. Terrain traversability analysis methods for unmanned ground vehicles: A survey

    OpenAIRE

    Papadakis, Panagiotis

    2013-01-01

    International audience; Motion planning for unmanned ground vehicles (UGV) constitutes a domain of research where several disciplines meet, ranging from artificial intelligence and machine learning to robot perception and computer vision. In view of the plurality of related applications such as planetary exploration, search and rescue, agriculture, mining and off-road exploration, the aim of the present survey is to review the field of 3D terrain traversability analysis that is employed at a ...

  2. A Survey of Terrain Modeling Technologies and Techniques

    Science.gov (United States)

    2007-09-01

    esthetically pleasing, is not the best representa- tion of the true digital terrain elevations. The results also show that this Automatic Feature...economical and easily available in the market . • With independent control of quality of data immediately after delivery and before final payment...recommended by the GDATP/GIST team). Collection LIDAR data from an airplane must more economical and easily available in market . • With independent

  3. Functional Decomposition of Modeling and Simulation Terrain Database Generation Process

    Science.gov (United States)

    2008-09-19

    necessary, the method selected depends upon the relative maturity of functionality between the soft - ware products. Attribute values such as the...most important M&S key thrust areas are (1) credibly modeling mili- tary systems and Soldiers and (2) developing realistic environmental representa...distributor of M&S terrain databases is a logical extension of its geospatial core competencies and consistent with its role as an Army Geo - spatial

  4. An Intelligent Assistant for Construction of Terrain Databases

    OpenAIRE

    Rowe, Neil C.; Reed, Chris; Jackson, Leroy; Baer, Wolfgang

    1998-01-01

    1998 Command and Control Research and Technology Symposium, Monterey CA, June 1998, 481-486. We describe TELLUSPLAN, an intelligent assistant for the problem of bargaining between user goals and system resources in the integration of terrain databases from separate source databases. TELLUSPLAN uses nondeterministic methods from artificial intelligence and a detailed cost model to infer the most reasonable compromise with the user's needs. Supported by the Army Artificial Int...

  5. Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program

    Science.gov (United States)

    2017-05-09

    been edited and appeared in the journal Boundary Layer Meteorology. It is entitled: Mountainous Terrain: Results from MATERJ-IORN-X (June 2016...Nocturnal Boundary-Layer Evolution on a Slope at the Foot of a Desert Mountain , Journal of Applied Meteorology. 54( 4), 732-751. Marjanovic, N., Wharton...Layer Heights over an Isolated Mountain : Cases from the MA TERHORN-2012 Experiment. Journal o.f Applied Meteorology and Climatology, 55, 1927- 1952

  6. The effect of terrain slope on firefighter safety zone effectiveness

    Science.gov (United States)

    Bret Butler; J. Forthofer; K. Shannon; D. Jimenez; D. Frankman

    2010-01-01

    The current safety zone guidelines used in the US were developed based on the assumption that the fire and safety zone were located on flat terrain. The minimum safe distance for a firefighter to be from a flame was calculated as that corresponding to a radiant incident energy flux level of 7.0kW-m-2. Current firefighter safety guidelines are based on the assumption...

  7. The Potential Impact of Vertical Sampling Uncertainty on ICESat-2/ATLAS Terrain and Canopy Height Retrievals for Multiple Ecosystems

    Directory of Open Access Journals (Sweden)

    Amy L. Neuenschwander

    2016-12-01

    Full Text Available With a planned launch no later than September 2018, the Ice, Cloud and land Elevation Satellite-2 (ICESat-2 will provide a global distribution of geodetic elevation measurements for both the terrain surface and relative canopy heights. The Advanced Topographic Laser Altimeter System (ATLAS instrument on-board ICESat-2 is a LiDAR system sensitive to the photon level. The photon-counting technology has many advantages for space-based altimetry, but also has challenges, particularly with delineating the signal from background noise. As such, a current unknown facing the ecosystem community is the performance of ICESat-2 for terrain and canopy height retrievals. This paper aims to provide the science user community of ICESat-2 land/vegetation data products with a realistic understanding of the performance characteristics and potential uncertainties related to the vertical sampling error, which includes the error in the perceived height value and the measurement precision. Terrain and canopy heights from simulated ICESat-2 data are evaluated against the airborne LiDAR ground truth values to provide a baseline performance uncertainty for multiple ecosystems. Simulation results for wooded savanna and boreal forest result in a mean bias error and error uncertainty (precision for terrain height retrievals at 0.06 m (0.24 m RMSE and −0.13 m (0.77 m RMSE. In contrast, results over ecosystems with dense vegetation show terrain errors of 1.93 m (1.66 m RMSE and 2.52 m (3.18 m RMSE, indicating problems extracting terrain height due to diminished ground returns. Simulated top of canopy heights from ICESat-2 underestimated true top of canopy returns for all types analyzed with errors ranging from 0.28 m (1.39 m RMSE to 1.25 m (2.63 m RMSE. These results comprise a first step in a comprehensive evaluation of ICESat-2 anticipated performance. Future steps will include solar noise impact analysis and investigation into performance discrepancy between visible and

  8. Topological Landscapes: A Terrain Metaphor for ScientificData

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Gunther H.; Bremer, Peer-Timo; Pascucci, Valerio

    2007-08-01

    Scientific visualization and illustration tools are designed to help people understand the structure and complexity of scientific data with images that are as informative and intuitive as possible. In this context, the use of metaphors plays an important role, since they make complex information easily accessible by using commonly known concepts. In this paper we propose a new metaphor, called 'Topological Landscapes', which facilitates understanding the topological structure of scalar functions. The basic idea is to construct a terrain with the same topology as a given dataset and to display the terrain as an easily understood representation of the actual input data. In this projection from an n-dimensional scalar function to a two-dimensional (2D) model we preserve function values of critical points, the persistence (function span) of topological features, and one possible additional metric property (in our examples volume). By displaying this topologically equivalent landscape together with the original data we harness the natural human proficiency in understanding terrain topography and make complex topological information easily accessible.

  9. ROAMing terrain (Real-time Optimally Adapting Meshes)

    Energy Technology Data Exchange (ETDEWEB)

    Duchaineau, M.; Wolinsky, M.; Sigeti, D.E.; Miller, M.C.; Aldrich, C.; Mineev, M.

    1997-07-01

    Terrain visualization is a difficult problem for applications requiring accurate images of large datasets at high frame rates, such as flight simulation and ground-based aircraft testing using synthetic sensor stimulation. On current graphics hardware, the problem is to maintain dynamic, view-dependent triangle meshes and texture maps that produce good images at the required frame rate. We present an algorithm for constructing triangle meshes that optimizes flexible view-dependent error metrics, produces guaranteed error bounds, achieves specified triangle counts directly, and uses frame-to-frame coherence to operate at high frame rates for thousands of triangles per frame. Our method, dubbed Real-time Optimally Adapting Meshes (ROAM), uses two priority queues to drive split and merge operations that maintain continuous triangulations built from pre-processed bintree triangles. We introduce two additional performance optimizations: incremental triangle stripping and priority-computation deferral lists. ROAM execution time is proportionate to the number of triangle changes per frame, which is typically a few percent of the output mesh size, hence ROAM performance is insensitive to the resolution and extent of the input terrain. Dynamic terrain and simple vertex morphing are supported.

  10. CFD three dimensional wake analysis in complex terrain

    Science.gov (United States)

    Castellani, F.; Astolfi, D.; Terzi, L.

    2017-11-01

    Even if wind energy technology is nowadays fully developed, the use of wind energy in very complex terrain is still challenging. In particular, it is challenging to characterize the combination effects of wind ow over complex terrain and wake interactions between nearby turbines and this has a practical relevance too, for the perspective of mitigating anomalous vibrations and loads as well improving the farm efficiency. In this work, a very complex terrain site has been analyzed through a Reynolds-averaged CFD (Computational Fluid Dynamics) numerical wind field model; in the simulation the inuence of wakes has been included through the Actuator Disk (AD) approach. In particular, the upstream turbine of a cluster of 4 wind turbines having 2.3 MW of rated power is studied. The objective of this study is investigating the full three-dimensional wind field and the impact of three-dimensionality on the evolution of the waked area between nearby turbines. A post-processing method of the output of the CFD simulation is developed and this allows to estimate the wake lateral deviation and the wake width. The reliability of the numerical approach is inspired by and crosschecked through the analysis of the operational SCADA (Supervisory Control and Data Acquisition) data of the cluster of interest.

  11. The influence of surface soil physicochemistry on the edaphic bacterial communities in contrasting terrain types of the Central Namib Desert.

    Science.gov (United States)

    Gombeer, S; Ramond, J-B; Eckardt, F D; Seely, M; Cowan, D A

    2015-09-01

    Notwithstanding, the severe environmental conditions, deserts harbour a high diversity of adapted micro-organisms. In such oligotrophic environments, soil physicochemical characteristics play an important role in shaping indigenous microbial communities. This study investigates the edaphic bacterial communities of three contrasting desert terrain types (gravel plains, sand dunes and ephemeral rivers) with different surface geologies in the Central Namib Desert. For each site, we evaluated surface soil physicochemistries and used explorative T-RFLP methodology to get an indication of bacterial community diversities. While grain size was an important parameter in separating the three terrain types physicochemically and specific surface soil types could be distinguished, the desert edaphic bacterial communities displayed a high level of local spatial heterogeneity. Ten variables contributed significantly (P Desert and stress the importance of recording a wide variety of environmental descriptors to comprehensively assess the role of edaphic parameters in shaping microbial communities. © 2015 John Wiley & Sons Ltd.

  12. SPATIAL RESOLUTION EFFECTS OF DIGITAL TERRAIN MODELS ON LANDSLIDE SUSCEPTIBILITY ANALYSIS

    Directory of Open Access Journals (Sweden)

    K. T. Chang

    2016-06-01

    Full Text Available The purposes of this study are to identify the maximum number of correlated factors for landslide susceptibility mapping and to evaluate landslide susceptibility at Sihjhong river catchment in the southern Taiwan, integrating two techniques, namely certainty factor (CF and artificial neural network (ANN. The landslide inventory data of the Central Geological Survey (CGS, MOEA in 2004-2014 and two digital elevation model (DEM datasets including a 5-meter LiDAR DEM and a 30-meter Aster DEM were prepared. We collected thirteen possible landslide-conditioning factors. Considering the multi-collinearity and factor redundancy, we applied the CF approach to optimize these thirteen conditioning factors. We hypothesize that if the CF values of the thematic factor layers are positive, it implies that these conditioning factors have a positive relationship with the landslide occurrence. Therefore, based on this assumption and positive CF values, seven conditioning factors including slope angle, slope aspect, elevation, terrain roughness index (TRI, terrain position index (TPI, total curvature, and lithology have been selected for further analysis. The results showed that the optimized-factors model provides a better accuracy for predicting landslide susceptibility in the study area. In conclusion, the optimized-factors model is suggested for selecting relative factors of landslide occurrence.

  13. Environmental aspects of Kaiser S2 harvester utilization in mountain terrains

    Directory of Open Access Journals (Sweden)

    Jozef Slugeň

    2012-01-01

    Full Text Available This paper deals with evaluating the ecological impacts of Kaiser S2 harvester utilization in mountain terrains. The harvester was used in bark beetle calamity and secondary felling in mixed forest (spruce, fir, beech stand with average incline of 70%. Assisting its movement in these extreme conditions were two supporting bases, which were used to stabilize it in the stand. Our aim was to determine the damage to the trees, underwood and stand soil. The resulting damage of remaining stand was 6.19%, which is, considering the demanding terrain conditions and in comparison with the outcomes of other research, a relatively acceptable value. Damage to the underwood was not found, due to its insufficient height and low representation. Measurements of damage to the soil by its compression indicated that the heaviest damage was under the supporting bases, where a heavy surface damage was found by creation of holes up to 15 cm deep. This type of damage is not dangerous, because it does not create a continuous track dangerous in storm rainfall and subsequent soil erosion. Soil compression in the track and on unimpaired soil reached lower levels. All of the measurements of compression by static penetration were carried out only to the depth of 15 cm due to high soil skeleton. This also negatively affected the measurements, which had to be repeated in many cases.

  14. Evolutionary View Planning for Optimized UAV Terrain Modeling in a Simulated Environment

    Directory of Open Access Journals (Sweden)

    Ronald A. Martin

    2015-12-01

    Full Text Available This work demonstrates the use of genetic algorithms in optimized view planning for 3D reconstruction applications using small unmanned aerial vehicles (UAVs. The quality of UAV site models is currently highly dependent on manual pilot operations or grid-based automation solutions. When applied to 3D structures, these approaches can result in gaps in the total coverage or inconsistency in final model resolution. Genetic algorithms can effectively explore the search space to locate image positions that produce high quality models in terms of coverage and accuracy. A fitness function is defined, and optimization parameters are selected through semi-exhaustive search. A novel simulation environment for evaluating view plans is demonstrated using terrain generation software. The view planning algorithm is tested in two separate simulation cases: a water drainage structure and a reservoir levee, as representative samples of infrastructure monitoring. The optimized flight plan is compared against three alternate flight plans in each case. The optimized view plan is found to yield terrain models with up to 43% greater accuracy than a standard grid flight pattern, while maintaining comparable coverage and completeness.

  15. A Force-Sensing System on Legs for Biomimetic Hexapod Robots Interacting with Unstructured Terrain.

    Science.gov (United States)

    Zhang, He; Wu, Rui; Li, Changle; Zang, Xizhe; Zhang, Xuehe; Jin, Hongzhe; Zhao, Jie

    2017-06-27

    The tiger beetle can maintain its stability by controlling the interaction force between its legs and an unstructured terrain while it runs. The biomimetic hexapod robot mimics a tiger beetle, and a comprehensive force sensing system combined with certain algorithms can provide force information that can help the robot understand the unstructured terrain that it interacts with. This study introduces a complicated leg force sensing system for a hexapod robot that is the same for all six legs. First, the layout and configuration of sensing system are designed according to the structure and sizes of legs. Second, the joint toque sensors, 3-DOF foot-end force sensor and force information processing module are designed, and the force sensor performance parameters are tested by simulations and experiments. Moreover, a force sensing system is implemented within the robot control architecture. Finally, the experimental evaluation of the leg force sensor system on the hexapod robot is discussed and the performance of the leg force sensor system is verified.

  16. Automatic representation of urban terrain models for simulations on the example of VBS2

    Science.gov (United States)

    Bulatov, Dimitri; Häufel, Gisela; Solbrig, Peter; Wernerus, Peter

    2014-10-01

    Virtual simulations have been on the rise together with the fast progress of rendering engines and graphics hardware. Especially in military applications, offensive actions in modern peace-keeping missions have to be quick, firm and precise, especially under the conditions of asymmetric warfare, non-cooperative urban terrain and rapidly developing situations. Going through the mission in simulation can prepare the minds of soldiers and leaders, increase selfconfidence and tactical awareness, and finally save lives. This work is dedicated to illustrate the potential and limitations of integration of semantic urban terrain models into a simulation. Our system of choice is Virtual Battle Space 2, a simulation system created by Bohemia Interactive System. The topographic object types that we are able to export into this simulation engine are either results of the sensor data evaluation (building, trees, grass, and ground), which is done fully-automatically, or entities obtained from publicly available sources (streets and water-areas), which can be converted into the system-proper format with a few mouse clicks. The focus of this work lies in integrating of information about building façades into the simulation. We are inspired by state-of the art methods that allow for automatic extraction of doors and windows in laser point clouds captured from building walls and thus increase the level of details of building models. As a consequence, it is important to simulate these animationable entities. Doing so, we are able to make accessible some of the buildings in the simulation.

  17. 3D Finite Element Analysis of PWA-Oil Sand Terrain System Interaction

    Directory of Open Access Journals (Sweden)

    Y. Li

    2012-01-01

    Full Text Available A simulator for analyzing the interaction between the oil sand terrain and a pipe wagon articulating (PWA system has been developed in this paper. An elastic-plastic oil sand model was built based on the finite element analysis (FEA method and von Mises yield criterion using the Algor mechanical event simulation (MES software. The three-dimensional (3D distribution of the stress, strain, nodal displacement, and deformed shape of the oil sands was animated at an environmental temperature of 25°C. The 3D behavior of the oil sand terrain was investigated with different loading conditions. The effect of the load and contact area on the stress and nodal displacement was analyzed, respectively. The results indicate that both the max stress and max nodal displacement increase with the load varying from 0 to 3.6+7 N and decrease with the contact area varying from 2 to 10 m2. The method presented in this paper forms the basis for evaluating the bearing capacity of oil sand ground.

  18. A Field Study of Atmospheric Icing Analysis in a Complex Terrain of the High North

    Directory of Open Access Journals (Sweden)

    Taimur Rashid

    2014-12-01

    Full Text Available Analyses of atmospheric icing events hold the key for computing the significant parameters leading to icing load calculations. In the cold regions of the high north, atmospheric icing loads on structures become important when it comes to design and safety of infrastructures. Furthermore, icing load calculations over a certain period of time provide a vital input for designers to improve the safety of structures. Patterns of icing events can be evaluated in correlation with other meteorological parameters such as atmospheric temperature, relative humidity and wind speed to better estimate icing loads. A field study has been performed in the complex terrain of northern Norway, by the atmospheric icing research team of Narvik University College, where customized meteorological atmospheric ice monitoring stations were installed to study atmospheric icing events in relation with the associated weather parameters. The meteorological parameters of three different sites in the vicinity of Narvik (68°25′14′ N17°33′36′ E were collected, sorted, averaged to standardized timeline and further validated with recordings of weathers parameters obtained from the national weather forecasts, where a good agreement was found. Analyses were mainly performed between accreted ice loads and associated meteorological parameters. The results presented can be used as base for the development of more detailed mathematical models for the better prediction of atmospheric icing events in complex terrains.

  19. Comparison of two air temperature gridding methods over complex terrain in China

    Science.gov (United States)

    Shi, Guoping; Sun, Zhian; Qiu, Xinfa; Zeng, Yan; Chen, Peng; Liu, Changjie

    2017-08-01

    This paper evaluates the monthly mean air temperature over complex terrain in China determined using two methods: Australian National University spline and GridMet_Climate_Temperature (grid meteorological and climatic temperature (GMCT)) models. It is found that the macroscopic patterns of the temperature distributions by the two methods are very similar. The comparison of modelled temperatures with observations from 40 verification stations shows that both methods have the same value of total mean absolute bias errors (MABE) of 0.43 °C. Since the observational data used are from meteorological observational stations which are located on horizontal flat and open areas, these evaluation results only represent those on the flat open areas. In order to evaluate the effects of topographical factors on the temperature, a concept of relief amplitude is defined. The temperatures are grouped according to range of the relief amplitudes, and variation of temperature with relief amplitudes is worked out. It is found that the temperature difference between the two models varies significantly with relief amplitudes. The averaged maximum difference can be as large as 12 °C in January when the relief amplitude is greater than 700 m. The reasons for the temperature difference are investigated, and they are due to the effects of topographical slopes and aspects. One model (GMCT) includes these effects while the other does not. The evaluation results demonstrate that it is necessary to include the effects of topographical factors in the model simulation in order to produce realistic temperature distributions in the complex terrain areas. The distributions of temperature on the northern and southern slopes are determined using the GMCT model, and the results show that the temperatures on the southern slopes are clearly greater than those of the northern slopes, especially in winter. These results can be used as a guide for the reasonable and sustainable utilization of heat

  20. Effective Albedo of Vegetated Terrain at L-Band

    Science.gov (United States)

    Kurum, Mehmet; O'Neill, Peggy E.; Lang, Roger H.

    2011-01-01

    This paper derives an explicit expression for an effective albedo of vegetated terrain from the zero- and multiple- order radiative transfer (RT) model comparison. The formulation establishes a direct physical link between the effective vegetation parameterization and the theoretical description of absorption and scattering within the canopy. The paper will present an evaluation of the derived albedo for corn canopies with data taken during an experiment at Alabama A&M Winfield A. Thomas Agricultural Research Station near Huntsville, Alabama in June, 1998. The test site consisted of two 50-m x 60-m plots - one with a bare surface and the other with grass cover - and four 30-m x 50-m plots of corn at different planting densities. One corn field was planted at a full density of 9.5 plants/sq m while the others were planted at 1/3, 1/2 and 2/3 of the full density. The fields were observed with a truck-mounted L-band radiometer at incident angle of 15 degree for the period of two weeks. Soil moisture (SM) changed daily due to irrigation and natural rainfall. Variations in gravimetric SM from 18 % to 34 % were seen during this period. Ground truth data, including careful characterization of the corn size and orientation statistics, and its dielectric, was also collected and used to simulate the effective albedo for the vegetation. The single-scattering albedo is defined as the fractional power scattered from individual vegetation constituents with respect to canopy extinction. It represents single-scattering properties of vegetation elements only, and is independent of ground properties. The values of the albedo get higher when there is dense vegetation (i.e. forest, mature corn, etc.) with scatterers, such as branches and trunks (or stalks in the case of corn), which are large with respect to the wavelength. This large albedo leads to a reduction in brightness temperature in the zero-order RT solution (known as tau-omega model). Higher-order multiple-scattering RT

  1. TERRAIN TECTONICS OF THE CENTRAL ASIAN FOLDED BELT

    Directory of Open Access Journals (Sweden)

    M. M. Buslov

    2014-01-01

    Full Text Available The terrain analysis concept envisages primarily a possibility of approximation of fragments / terrains of various geodynamic settings which belong to different plates. The terrain analysis can supplement the theory of plate tectonics in solving problems of geodynamics and tectonics of regions of the crust with complex structures. The Central Asian belt is among such complicated regions. Terrain structures occurred as a result of combined movements in the system of 'frontal' and/or oblique subduction – collision. In studies of geological objects, it is required first of all to prove their (vertical and horizontal autochthony in relations to each other and then proceed to paleogeodynamic, paleotectonic and paleogeographic reconstructions. Obviously, such a complex approach needs data to be obtained by a variety of research methods, including those applied to study geologic structures, stratigraphy, paleontology, paleogeography, lithothlogy, geochemistry, geochronology, paleomagnetism etc. Only by correlating such data collected from inter-disciplinary studies of the regions, it is possible to establish reliable characteristics of the geological settings and avoid mistakes and misinterpretations that may be associated with the 'stratigraphic' approach to solutions of both regional and global problems of geodynamics and tectonics of folded areas. The terrain analysis of the Central Asian folded belt suggests that its tectonic structure combines marginal continental rock complexes that were formed by the evolution of two major oceanic plates. One of them is the plate of the Paleo-Asian Ocean. As the analogue of the current Indo-Atlantic segment of Earth, it is characterised by the presence of continental blocks in the composition of the oceanic crust and the formation of oceanic basins resulting from the breakup of Rodinia and Gondvana. In the course of its evolution, super-continents disintegrated, and the blocks were reunited into the Kazakhstan

  2. TERRAIN TECTONICS OF THE CENTRAL ASIAN FOLDED BELT

    Directory of Open Access Journals (Sweden)

    M. M. Buslov

    2015-09-01

    Full Text Available The terrain analysis concept envisages primarily a possibility of approximation of fragments / terrains of various geodynamic settings which belong to different plates. The terrain analysis can supplement the theory of plate tectonics in solving problems of geodynamics and tectonics of regions of the crust with complex structures. The Central Asian belt is among such complicated regions. Terrain structures occurred as a result of combined movements in the system of 'frontal' and/or oblique subduction – collision. In studies of geological objects, it is required first of all to prove their (vertical and horizontal autochthony in relations to each other and then proceed to paleogeodynamic, paleotectonic and paleogeographic reconstructions. Obviously, such a complex approach needs data to be obtained by a variety of research methods, including those applied to study geologic structures, stratigraphy, paleontology, paleogeography, lithothlogy, geochemistry, geochronology, paleomagnetism etc. Only by correlating such data collected from inter-disciplinary studies of the regions, it is possible to establish reliable characteristics of the geological settings and avoid mistakes and misinterpretations that may be associated with the 'stratigraphic' approach to solutions of both regional and global problems of geodynamics and tectonics of folded areas. The terrain analysis of the Central Asian folded belt suggests that its tectonic structure combines marginal continental rock complexes that were formed by the evolution of two major oceanic plates. One of them is the plate of the Paleo-Asian Ocean. As the analogue of the current Indo-Atlantic segment of Earth, it is characterised by the presence of continental blocks in the composition of the oceanic crust and the formation of oceanic basins resulting from the breakup of Rodinia and Gondvana. In the course of its evolution, super-continents disintegrated, and the blocks were reunited into the Kazakhstan

  3. Linearized simulation of flow over wind farms and complex terrains.

    Science.gov (United States)

    Segalini, Antonio

    2017-04-13

    The flow over complex terrains and wind farms is estimated here by numerically solving the linearized Navier-Stokes equations. The equations are linearized around the unperturbed incoming wind profile, here assumed logarithmic. The Boussinesq approximation is used to model the Reynolds stress with a prescribed turbulent eddy viscosity profile. Without requiring the boundary-layer approximation, two new linear equations are obtained for the vertical velocity and the wall-normal vorticity, with a reduction in the computational cost by a factor of 8 when compared with a primitive-variables formulation. The presence of terrain elevation is introduced as a vertical coordinate shift, while forestry or wind turbines are included as body forces, without any assumption about the wake structure for the turbines. The model is first validated against some available experiments and simulations, and then a simulation of a wind farm over a Gaussian hill is performed. The speed-up effect of the hill is clearly beneficial in terms of the available momentum upstream of the crest, while downstream of it the opposite can be said as the turbines face a decreased wind speed. Also, the presence of the hill introduces an additional spanwise velocity component that may also affect the turbines' operations. The linear superposition of the flow over the hill and the flow over the farm alone provided a first estimation of the wind speed along the farm, with discrepancies of the same order of magnitude for the spanwise velocity. Finally, the possibility of using a parabolic set of equations to obtain the turbulent kinetic energy after the linearized model is investigated with promising results.This article is part of the themed issue 'Wind energy in complex terrains'. © 2017 The Author(s).

  4. Linearized simulation of flow over wind farms and complex terrains

    Science.gov (United States)

    Segalini, Antonio

    2017-03-01

    The flow over complex terrains and wind farms is estimated here by numerically solving the linearized Navier-Stokes equations. The equations are linearized around the unperturbed incoming wind profile, here assumed logarithmic. The Boussinesq approximation is used to model the Reynolds stress with a prescribed turbulent eddy viscosity profile. Without requiring the boundary-layer approximation, two new linear equations are obtained for the vertical velocity and the wall-normal vorticity, with a reduction in the computational cost by a factor of 8 when compared with a primitive-variables formulation. The presence of terrain elevation is introduced as a vertical coordinate shift, while forestry or wind turbines are included as body forces, without any assumption about the wake structure for the turbines. The model is first validated against some available experiments and simulations, and then a simulation of a wind farm over a Gaussian hill is performed. The speed-up effect of the hill is clearly beneficial in terms of the available momentum upstream of the crest, while downstream of it the opposite can be said as the turbines face a decreased wind speed. Also, the presence of the hill introduces an additional spanwise velocity component that may also affect the turbines' operations. The linear superposition of the flow over the hill and the flow over the farm alone provided a first estimation of the wind speed along the farm, with discrepancies of the same order of magnitude for the spanwise velocity. Finally, the possibility of using a parabolic set of equations to obtain the turbulent kinetic energy after the linearized model is investigated with promising results. This article is part of the themed issue 'Wind energy in complex terrains'.

  5. Atmospheric stability effects on wind fields and scalar mixing within and just above a subalpine forest in sloping terrain

    Science.gov (United States)

    Burns, Sean P.; Sun, Jielun; Lenschow, D.H.; Oncley, S.P.; Stephens, B.B.; Yi, C.; Anderson, D.E.; Hu, Jiawen; Monson, Russell K.

    2011-01-01

    Air temperature Ta, specific humidity q, CO2 mole fraction ??c, and three-dimensional winds were measured in mountainous terrain from five tall towers within a 1 km region encompassing a wide range of canopy densities. The measurements were sorted by a bulk Richardson number Rib. For stable conditions, we found vertical scalar differences developed over a "transition" region between 0.05 1), the vertical scalar differences reached a maximum and remained fairly constant with increasing stability. The relationships q and ??c have with Rib are explained by considering their sources and sinks. For winds, the strong momentum absorption in the upper canopy allows the canopy sublayer to be influenced by pressure gradient forces and terrain effects that lead to complex subcanopy flow patterns. At the dense-canopy sites, soil respiration coupled with wind-sheltering resulted in CO2 near the ground being 5-7 ??mol mol-1 larger than aloft, even with strong above-canopy winds (near-neutral conditions). We found Rib-binning to be a useful tool for evaluating vertical scalar mixing; however, additional information (e.g., pressure gradients, detailed vegetation/topography, etc.) is needed to fully explain the subcanopy wind patterns. Implications of our results for CO2 advection over heterogenous, complex terrain are discussed. ?? 2010 Springer Science+Business Media B.V.

  6. IMPACT OF DIFFERENT TOPOGRAPHIC CORRECTIONS ON PREDICTION ACCURACY OF FOLIAGE PROJECTIVE COVER (FPC IN A TOPOGRAPHICALLY COMPLEX TERRAIN

    Directory of Open Access Journals (Sweden)

    S. Ediriweera

    2012-07-01

    Full Text Available Quantitative retrieval of land surface biological parameters (e.g. foliage projective cover [FPC] and Leaf Area Index is crucial for forest management, ecosystem modelling, and global change monitoring applications. Currently, remote sensing is a widely adopted method for rapid estimation of surface biological parameters in a landscape scale. Topographic correction is a necessary pre-processing step in the remote sensing application for topographically complex terrain. Selection of a suitable topographic correction method on remotely sensed spectral information is still an unresolved problem. The purpose of this study is to assess the impact of topographic corrections on the prediction of FPC in hilly terrain using an established regression model. Five established topographic corrections [C, Minnaert, SCS, SCS+C and processing scheme for standardised surface reflectance (PSSSR] were evaluated on Landsat TM5 acquired under low and high sun angles in closed canopied subtropical rainforest and eucalyptus dominated open canopied forest, north-eastern Australia. The effectiveness of methods at normalizing topographic influence, preserving biophysical spectral information, and internal data variability were assessed by statistical analysis and by comparing field collected FPC data. The results of statistical analyses show that SCS+C and PSSSR perform significantly better than other corrections, which were on less overcorrected areas of faintly illuminated slopes. However, the best relationship between FPC and Landsat spectral responses was obtained with the PSSSR by producing the least residual error. The SCS correction method was poor for correction of topographic effect in predicting FPC in topographically complex terrain.

  7. Wind farm design in complex terrain: the FarmOpt methodology

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong; Hansen, Kurt Schaldemose

    Designing wind farms in complex terrain is becoming more and more important, especially for countries like China, where a large portion of the territory is featured as complex terrain. Although potential richer wind resources could be expected at complex terrain sites (thanks to the terrain effects......), they also expose many challenges for wind farm designers/developers. In this study, we present the FarmOpt methodology for designing wind farms in complex terrain, which combines the state-of-the-art wind resource assessment methods with engineering wake models adapted for complex terrain and advanced...... layout optimization algorithms. Various constraints are also modelled and considered in the design optimization problem for maximizing the annual energy production (AEP). A case study is presented to illustrate the effectiveness of the methodology. Further developments of the FarmOpt tool are also...

  8. Program Merges SAR Data on Terrain and Vegetation Heights

    Science.gov (United States)

    Siqueira, Paul; Hensley, Scott; Rodriguez, Ernesto; Simard, Marc

    2007-01-01

    X/P Merge is a computer program that estimates ground-surface elevations and vegetation heights from multiple sets of data acquired by the GeoSAR instrument [a terrain-mapping synthetic-aperture radar (SAR) system that operates in the X and bands]. X/P Merge software combines data from X- and P-band digital elevation models, SAR backscatter magnitudes, and interferometric correlation magnitudes into a simplified set of output topographical maps of ground-surface elevation and tree height.

  9. Complementary terrain/single beacon-based AUV navigation

    Digital Repository Service at National Institute of Oceanography (India)

    Maurya, P.; Curado, T.F.; António, P.

    Complementary Terrain/Single Beacon-Based AUV Navigation � Pramod Maurya ∗,∗∗ Francisco Curado Teixeira ∗∗∗ Anto´nio Pascoal ∗ ∗ Laboratory for Robotics and Systems in Engineering and Science, Instituto Superior Te´cnico, Av. Rovisco Pais 1, 1049-001 Lisboa... new architecture that brings together TAN and SBN whereby a TAN algorithm is also fed with the ranges between the marine robot and an underwater transponder installed at a known location. Our aim is to show analytically, via the computation...

  10. Assessing the importance of terrain parameters on glide avalanche release

    Science.gov (United States)

    Peitzsch, Erich H.; Hendrikx, Jordy; Fagre, Daniel B.

    2014-01-01

    Glide snow avalanches are dangerous and difficult to predict. Despite recent research there is still a lack of understanding regarding the controls of glide avalanche release. Glide avalanches often occur in similar terrain or the same locations annually and observations suggest that topography may be critical. Thus, to gain an understanding of the terrain component of these types of avalanches we examined terrain parameters associated with glide avalanche release as well as areas of consistent glide crack formation but no subsequent avalanches. Glide avalanche occurrences visible from the Going-to-the-Sun Road corridor in Glacier National Park, Montana from 2003-2013 were investigated using an avalanche database derived of daily observations each year from April 1 to June 15. This yielded 192 glide avalanches in 53 distinct avalanche paths. Each avalanche occurrence was digitized in a GIS using satellite, oblique, and aerial imagery as reference. Topographical parameters such as area, slope, aspect, elevation and elevation were then derived for the entire dataset utilizing GIS tools and a 10m DEM. Land surface substrate and surface geology were derived from National Park Service Inventory and Monitoring maps and U.S. Geological Survey surface geology maps, respectively. Surface roughness and glide factor were calculated using a four level classification index. . Then, each avalanche occurrence was aggregated to general avalanche release zones and the frequencies were compared. For this study, glide avalanches released in elevations ranging from 1300 to 2700 m with a mean aspect of 98 degrees (east) and a mean slope angle of 38 degrees. The mean profile curvature for all glide avalanches was 0.15 and a plan curvature of -0.01, suggesting a fairly linear surface (i.e. neither convex nor concave). The glide avalanches occurred in mostly bedrock made up of dolomite and limestone slabs and talus deposits with very few occurring in alpine meadows. However, not all glide

  11. Micro- and meso-scale effects of forested terrain

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Mann, Jakob; Sogachev, Andrey

    2011-01-01

    The height and rotor diameter of modern wind turbines are so extensive, that the wind conditions they encounter often are well above the surface layer, where traditionally it is assumed that wind direction and turbulent fluxes are constant with respect to height, if the surface is homogenous...... scales are the height of the planetary boundary layer and the Monin-Obukhov length, which both are related to the energy balance of the surface. Examples of important micro- and meso-scale effects of forested terrain are shown using data and model results from recent and ongoing experiments. For micro...

  12. Towards Real-Time Detection of Gait Events on Different Terrains Using Time-Frequency Analysis and Peak Heuristics Algorithm.

    Science.gov (United States)

    Zhou, Hui; Ji, Ning; Samuel, Oluwarotimi Williams; Cao, Yafei; Zhao, Zheyi; Chen, Shixiong; Li, Guanglin

    2016-10-01

    Real-time detection of gait events can be applied as a reliable input to control drop foot correction devices and lower-limb prostheses. Among the different sensors used to acquire the signals associated with walking for gait event detection, the accelerometer is considered as a preferable sensor due to its convenience of use, small size, low cost, reliability, and low power consumption. Based on the acceleration signals, different algorithms have been proposed to detect toe off (TO) and heel strike (HS) gait events in previous studies. While these algorithms could achieve a relatively reasonable performance in gait event detection, they suffer from limitations such as poor real-time performance and are less reliable in the cases of up stair and down stair terrains. In this study, a new algorithm is proposed to detect the gait events on three walking terrains in real-time based on the analysis of acceleration jerk signals with a time-frequency method to obtain gait parameters, and then the determination of the peaks of jerk signals using peak heuristics. The performance of the newly proposed algorithm was evaluated with eight healthy subjects when they were walking on level ground, up stairs, and down stairs. Our experimental results showed that the mean F1 scores of the proposed algorithm were above 0.98 for HS event detection and 0.95 for TO event detection on the three terrains. This indicates that the current algorithm would be robust and accurate for gait event detection on different terrains. Findings from the current study suggest that the proposed method may be a preferable option in some applications such as drop foot correction devices and leg prostheses.

  13. Towards Real-Time Detection of Gait Events on Different Terrains Using Time-Frequency Analysis and Peak Heuristics Algorithm

    Directory of Open Access Journals (Sweden)

    Hui Zhou

    2016-10-01

    Full Text Available Real-time detection of gait events can be applied as a reliable input to control drop foot correction devices and lower-limb prostheses. Among the different sensors used to acquire the signals associated with walking for gait event detection, the accelerometer is considered as a preferable sensor due to its convenience of use, small size, low cost, reliability, and low power consumption. Based on the acceleration signals, different algorithms have been proposed to detect toe off (TO and heel strike (HS gait events in previous studies. While these algorithms could achieve a relatively reasonable performance in gait event detection, they suffer from limitations such as poor real-time performance and are less reliable in the cases of up stair and down stair terrains. In this study, a new algorithm is proposed to detect the gait events on three walking terrains in real-time based on the analysis of acceleration jerk signals with a time-frequency method to obtain gait parameters, and then the determination of the peaks of jerk signals using peak heuristics. The performance of the newly proposed algorithm was evaluated with eight healthy subjects when they were walking on level ground, up stairs, and down stairs. Our experimental results showed that the mean F1 scores of the proposed algorithm were above 0.98 for HS event detection and 0.95 for TO event detection on the three terrains. This indicates that the current algorithm would be robust and accurate for gait event detection on different terrains. Findings from the current study suggest that the proposed method may be a preferable option in some applications such as drop foot correction devices and leg prostheses.

  14. Digital terrain model generalization incorporating scale, semantic and cognitive constraints

    Science.gov (United States)

    Partsinevelos, Panagiotis; Papadogiorgaki, Maria

    2014-05-01

    Cartographic generalization is a well-known process accommodating spatial data compression, visualization and comprehension under various scales. In the last few years, there are several international attempts to construct tangible GIS systems, forming real 3D surfaces using a vast number of mechanical parts along a matrix formation (i.e., bars, pistons, vacuums). Usually, moving bars upon a structured grid push a stretching membrane resulting in a smooth visualization for a given surface. Most of these attempts suffer either in their cost, accuracy, resolution and/or speed. Under this perspective, the present study proposes a surface generalization process that incorporates intrinsic constrains of tangible GIS systems including robotic-motor movement and surface stretching limitations. The main objective is to provide optimized visualizations of 3D digital terrain models with minimum loss of information. That is, to minimize the number of pixels in a raster dataset used to define a DTM, while reserving the surface information. This neighborhood type of pixel relations adheres to the basics of Self Organizing Map (SOM) artificial neural networks, which are often used for information abstraction since they are indicative of intrinsic statistical features contained in the input patterns and provide concise and characteristic representations. Nevertheless, SOM remains more like a black box procedure not capable to cope with possible particularities and semantics of the application at hand. E.g. for coastal monitoring applications, the near - coast areas, surrounding mountains and lakes are more important than other features and generalization should be "biased"-stratified to fulfill this requirement. Moreover, according to the application objectives, we extend the SOM algorithm to incorporate special types of information generalization by differentiating the underlying strategy based on topologic information of the objects included in the application. The final

  15. The Cyber War: Maintaining and Controlling the Key Cyber Terrain of the Cyberspace Domain

    Science.gov (United States)

    2016-06-26

    geographic position. The definition of critical geographic terrain is clear. It may include a hill, a crossing point of a river or lake, or a valley.1...serve as a definition of key cyber terrain. The five planes are also illustrated in Figure 1.14 1) Supervisory Plane. The supervisory plane provides...terrain (e.g., adversary characteristics and possible adversary actions) are consistent. • A claim or hypothesis is meaningful to a specific real

  16. A Large-scale Terrain Transmission Mechanism Based on Hybrid P2P

    Directory of Open Access Journals (Sweden)

    YU Zhanwu

    2008-05-01

    Full Text Available Abstract: In large scale terrain roaning systems, the terrain visualization components are usually running on the localhost and terrain datasets are stored in the remote server.The server should guarantee the certain response delay and realize the teal-time tendering of huge-scale terrain when the number of user is limited. However. as the number of clients is quickly increasing, the server performance will no rapidly to satisfy the client real-time tendering requirement. Peer-to-peer (P2P technologies can efficiently reduce the bandwidth consumption of the server by the means of utilizing the client nodes' resource. The paper combines the C/S and peer-to-peer into 2 new data transmission mode for large terrain data transmission. First, it gives a new model for data transmission and new' structure for client node. Then it presents the management of peers and the look-up of terrain blocks in the new mode. Also it presents a kind of optimal algorithm for terrain block scheduling. The optimal algorithm can improve the terrain data transmitting speed and be adapted to the network change. Fault-tolerance and security are also considered in the paper. We build a prototype system and compare the new mechanism with traditional unicast mode. Experimental results have shown that the new mechanism can make the server's bad lighter than the old mode in the case of equal number of user requests and improve greatly the response time of the terrain block request.

  17. Estimation of wind velocity over a complex terrain using the Generalized Mapping Regressor

    Energy Technology Data Exchange (ETDEWEB)

    Beccali, M.; Marvuglia, A. [Dipartimento di Ricerche Energetiche ed Ambientali (DREAM), Universita degli Studi di Palermo, Viale delle Scienze - edificio 9, 90128 Palermo (Italy); Cirrincione, G. [Department de Genie Electrique, Universite de Picardie Jules Verne, 33, Rue Saint Leu, 80039 Amiens (France); Serporta, C. [ISSIA-CNR (Institute on Intelligent Systems for the Automation), Section of Palermo, Via Dante12, Palermo (Italy)

    2010-03-15

    Wind energy evaluation is an important goal in the conversion of energy systems to more environmentally friendly solutions. In this paper, we present a novel approach to wind speed spatial estimation on the isle of Sicily (Italy): an incremental self-organizing neural network (Generalized Mapping Regressor - GMR) is coupled with exploratory data analysis techniques in order to obtain a map of the spatial distribution of the average wind speed over the entire region. First, the topographic surface of the island was modelled using two different neural techniques and by exploiting the information extracted from a digital elevation model of the region. Then, GMR was used for automatic modelling of the terrain roughness. Afterwards, a statistical analysis of the wind data allowed for the estimation of the parameters of the Weibull wind probability distribution function. In the last sections of the paper, the expected values of the Weibull distributions were regionalized using the GMR neural network. (author)

  18. The North America tapestry of time and terrain

    Science.gov (United States)

    Barton, Kate E.; Howell, David G.; Vigil, Jose F.

    2003-01-01

    The North America Tapestry of Time and Terrain (1:8,000,000 scale) is a product of the US Geological Survey in the I-map series (I-2781). This map was prepared in collaboration with the Geological Survey of Canada and the Mexican Consejo Recursos de Minerales. This cartographic Tapestry is woven from a geologic map and a shaded relief image. This digital combination reveals the geologic history of North America through the interrelation of rock type, topography and time. Regional surface processes as well as continent-scale tectonic events are exposed in the three dimensions of space and the fourth dimension, geologic time. The large map shows the varying age of bedrock underlying North America, while four smaller maps show the distribution of four principal types of rock: sedimentary, volcanic, plutonic and metamorphic.This map expands the original concept of the 2000 Tapestry of Time and Terrain, by José F. Vigil, Richard J. Pike and David G. Howell, which covered the conterminous United States. The U.S. Tapestry poster and website have been popular in classrooms, homes, and even the Google office building, and we anticipate the North America Tapestry will have a similarly wide appeal, and to a larger audience.

  19. Navigating a Mobile Robot Across Terrain Using Fuzzy Logic

    Science.gov (United States)

    Seraji, Homayoun; Howard, Ayanna; Bon, Bruce

    2003-01-01

    A strategy for autonomous navigation of a robotic vehicle across hazardous terrain involves the use of a measure of traversability of terrain within a fuzzy-logic conceptual framework. This navigation strategy requires no a priori information about the environment. Fuzzy logic was selected as a basic element of this strategy because it provides a formal methodology for representing and implementing a human driver s heuristic knowledge and operational experience. Within a fuzzy-logic framework, the attributes of human reasoning and decision- making can be formulated by simple IF (antecedent), THEN (consequent) rules coupled with easily understandable and natural linguistic representations. The linguistic values in the rule antecedents convey the imprecision associated with measurements taken by sensors onboard a mobile robot, while the linguistic values in the rule consequents represent the vagueness inherent in the reasoning processes to generate the control actions. The operational strategies of the human expert driver can be transferred, via fuzzy logic, to a robot-navigation strategy in the form of a set of simple conditional statements composed of linguistic variables. These linguistic variables are defined by fuzzy sets in accordance with user-defined membership functions. The main advantages of a fuzzy navigation strategy lie in the ability to extract heuristic rules from human experience and to obviate the need for an analytical model of the robot navigation process.

  20. Walking Robots Dynamic Control Systems on an Uneven Terrain

    Directory of Open Access Journals (Sweden)

    MUNTEANU, M. S.

    2010-05-01

    Full Text Available The paper presents ZPM dynamic control of walking robots, developing an open architecture real time control multiprocessor system, in view of obtaining new capabilities for walking robots. The complexity of the movement mechanism of a walking robot was taken into account, being a repetitive tilting process with numerous instable movements and which can lead to its turnover on an uneven terrain. The control system architecture for the dynamic robot walking is presented in correlation with the control strategy which contains three main real time control loops: balance robot control using sensorial feedback, walking diagram control with periodic changes depending on the sensorial information during each walk cycle, predictable movement control based on a quick decision from the previous experimental data. The results obtained through simulation and experiments show an increase in mobility, stability in real conditions and obtaining of high performances related to the possibility of moving walking robots on terrains with a configuration as close as possible to real situations, respectively developing new technological capabilities of the walking robot control systems for slope movement and walking by overtaking or going around obstacles.

  1. An extensible framework for provenance in human terrain visual analytics.

    Science.gov (United States)

    Walker, Rick; Slingsby, Aiden; Dykes, Jason; Xu, Kai; Wood, Jo; Nguyen, Phong H; Stephens, Derek; Wong, B L William; Zheng, Yongjun

    2013-12-01

    We describe and demonstrate an extensible framework that supports data exploration and provenance in the context of Human Terrain Analysis (HTA). Working closely with defence analysts we extract requirements and a list of features that characterise data analysed at the end of the HTA chain. From these, we select an appropriate non-classified data source with analogous features, and model it as a set of facets. We develop ProveML, an XML-based extension of the Open Provenance Model, using these facets and augment it with the structures necessary to record the provenance of data, analytical process and interpretations. Through an iterative process, we develop and refine a prototype system for Human Terrain Visual Analytics (HTVA), and demonstrate means of storing, browsing and recalling analytical provenance and process through analytic bookmarks in ProveML. We show how these bookmarks can be combined to form narratives that link back to the live data. Throughout the process, we demonstrate that through structured workshops, rapid prototyping and structured communication with intelligence analysts we are able to establish requirements, and design schema, techniques and tools that meet the requirements of the intelligence community. We use the needs and reactions of defence analysts in defining and steering the methods to validate the framework.

  2. Wind Power Curve Modeling in Simple and Complex Terrain

    Energy Technology Data Exchange (ETDEWEB)

    Bulaevskaya, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wharton, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Irons, Z. [Enel Green Power North America, Andover, MA (United States); Qualley, G. [Pentalum, Colleyville, TX (United States)

    2015-02-09

    Our previous work on wind power curve modeling using statistical models focused on a location with a moderately complex terrain in the Altamont Pass region in northern California (CA). The work described here is the follow-up to that work, but at a location with a simple terrain in northern Oklahoma (OK). The goal of the present analysis was to determine the gain in predictive ability afforded by adding information beyond the hub-height wind speed, such as wind speeds at other heights, as well as other atmospheric variables, to the power prediction model at this new location and compare the results to those obtained at the CA site in the previous study. While we reach some of the same conclusions at both sites, many results reported for the CA site do not hold at the OK site. In particular, using the entire vertical profile of wind speeds improves the accuracy of wind power prediction relative to using the hub-height wind speed alone at both sites. However, in contrast to the CA site, the rotor equivalent wind speed (REWS) performs almost as well as the entire profile at the OK site. Another difference is that at the CA site, adding wind veer as a predictor significantly improved the power prediction accuracy. The same was true for that site when air density was added to the model separately instead of using the standard air density adjustment. At the OK site, these additional variables result in no significant benefit for the prediction accuracy.

  3. Compliant Biped Walking on Uneven Terrain with Point Feet

    Directory of Open Access Journals (Sweden)

    Wenqi Hou

    2016-03-01

    Full Text Available In this paper, we aim to realize compliant biped walking on uneven terrain with point feet. A control system is designed for a 5-link planar biped walker. According to the role that each leg plays, the control system is decomposed into two parts: the swing leg control and the support leg control. The trajectory of the swing foot is generated in real-time to regulate the walking speed. By considering the reaction torque of the swing leg's hip joint as disturbance, a sliding model controller is implemented at the support leg's hip joint to control the torso's posture angle. In order to make sure the landing foot does not rebound after impact, the vertical contact force control is set as the internal loop of the hip's height control. In simulation, the control system is tested on a virtual 5-link planar biped walker in Matlab. Finally, stable biped walking is realized on uneven terrain with roughness up to 2cm.

  4. Autonomous Path Tracking Steering Controller for Extraterrestrial Terrain Exporation Rover

    Science.gov (United States)

    Ahmed, Mohammed; Sonsalla, Roland; Kirchner, Frank

    Extraterrestrial surface missions typically use a robotic rover platform to carry the science instrumentation (e.g.,the twin MER rovers). Due to the risks in the rover path (i.e. low trafficability of unrecognized soil patches), it is proposed in the FASTER footnote{\\url{https://www.faster-fp7-space.eu}} project that two rovers should be used. A micro scout rover is used for determining the traversability of the terrain and collaborate with a primary rover to lower the risk of entering hazardous areas. That will improve the mission safety and the effective traverse speed for planetary rover exploration. This paper presents the design and implementation of the path following controller for micro scout rover. The objective to synthesize a control law which allows the rover to autonomously follow a desired path in a stable manner. Furthermore, the software architecture controlling the rover and all its subsystems is depicted. The performance of the designed controller is discussed and demonstrated with realistic simulations and experiments, conclusions and an outlook of future work are also given. Key words: Micro Rover, Scout Rover, Mars Exploration, Multi-Rover Team, Mobile, All-Terrain, Hybrid-Legged Wheel, Path Following, Automatic Steer, nonlinear systems.

  5. Stereo-vision-based terrain mapping for off-road autonomous navigation

    Science.gov (United States)

    Rankin, Arturo L.; Huertas, Andres; Matthies, Larry H.

    2009-05-01

    Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as nogo regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

  6. Stereo Vision Based Terrain Mapping for Off-Road Autonomous Navigation

    Science.gov (United States)

    Rankin, Arturo L.; Huertas, Andres; Matthies, Larry H.

    2009-01-01

    Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as no-go regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

  7. LiDAR-mast deviations in complex terrain and their simulation using CFD

    Directory of Open Access Journals (Sweden)

    Tobias Klaas

    2015-11-01

    Full Text Available LiDARs (Light Detection and Ranging are becoming important tools for wind resource assessments in all kinds of terrain. Compared to mast measurements, mobility and flexibility are their greatest benefits. However, care needs to be taken when setting up a measurement campaign. The influence of complex terrain on the wind leads to inhomogeneous flow. This can cause considerable errors in ground based mono-static LiDAR measurements due to their measurement principle and simplifying assumptions.Within this work, wind measurements from Fraunhofer IWES’s 200 m research mast in complex terrain at “Rödeser Berg” in Kassel, Germany, and a pulsed Doppler LiDAR (Leosphere windcube, located at the mast, are compared. The relative deviation between the measurements of the horizontal wind speed by the LiDAR and the mast (LiDAR-mast deviations varies with wind direction and height. It ranges from about −4 % underestimation to +2.5 % overestimation by the LiDAR - for heights between 120 and 200 m. Two steady-state Reynolds-Averaged-Navier-Stokes (RANS Computational Fluid Dynamics (CFD-models and a model based on linearized Navier-Stokes Equations were used to estimate the LiDAR error from a flow simulation. Model results were evaluated depending on model parameterisation such as forest height and density. Given the right parameterisations – especially for the forest model – the CFD-models showed a good performance when compared to the observed LiDAR-mast deviations. These simulations can thus be used to correct the LiDAR error induced by the complex flow.To demonstrate variations of LiDAR errors due to choice of measurement location, one of the models was run to calculate the wind flow in an area of 2×2km2$2\\times2\\,\\text{km}^{2}$ around the 200 m measurement mast. This allows the visualization of the estimated LiDAR errors to characterize measurement locations. Results showed the significant variation of measurement errors due to

  8. Real-time terrain storage generation from multiple sensors towards mobile robot operation interface.

    Science.gov (United States)

    Song, Wei; Cho, Seoungjae; Xi, Yulong; Cho, Kyungeun; Um, Kyhyun

    2014-01-01

    A mobile robot mounted with multiple sensors is used to rapidly collect 3D point clouds and video images so as to allow accurate terrain modeling. In this study, we develop a real-time terrain storage generation and representation system including a nonground point database (PDB), ground mesh database (MDB), and texture database (TDB). A voxel-based flag map is proposed for incrementally registering large-scale point clouds in a terrain model in real time. We quantize the 3D point clouds into 3D grids of the flag map as a comparative table in order to remove the redundant points. We integrate the large-scale 3D point clouds into a nonground PDB and a node-based terrain mesh using the CPU. Subsequently, we program a graphics processing unit (GPU) to generate the TDB by mapping the triangles in the terrain mesh onto the captured video images. Finally, we produce a nonground voxel map and a ground textured mesh as a terrain reconstruction result. Our proposed methods were tested in an outdoor environment. Our results show that the proposed system was able to rapidly generate terrain storage and provide high resolution terrain representation for mobile mapping services and a graphical user interface between remote operators and mobile robots.

  9. Tagungsbericht „Terrain vague: Die Brache in den Stadt- und Kulturwissenschaften“

    Directory of Open Access Journals (Sweden)

    Jacqueline Maria Broich

    2015-07-01

    Full Text Available Zum DFG-Projekt „Terrain vague: Ästhetik und Poetik urbaner Zwischenräume in der französischen Moderne“ (Romanisches Seminar der Universität zu Köln, Projektleiter Wolfram Nitsch und zum Workshop vom 24. und 25. April 2015 „Terrain vague: Die Brache in den Stadt- und Raumwissenschaften“

  10. The influence to source of data for accuracy on digital terrain models (DTM

    Directory of Open Access Journals (Sweden)

    Bajat Branislav

    2005-01-01

    Full Text Available The overview of the contemporary data acquisition methods for Digital Terrain Models (DTM, as well as the accuracy of data provided by these methods, are given in this article. The procedure of the accuracy estimation for DTM which is produced by digitizing of topographic maps and test points obtained by GPS technology and aerophotogrammetric terrain surveying, is presented.

  11. Real-Time Terrain Storage Generation from Multiple Sensors towards Mobile Robot Operation Interface

    Directory of Open Access Journals (Sweden)

    Wei Song

    2014-01-01

    Full Text Available A mobile robot mounted with multiple sensors is used to rapidly collect 3D point clouds and video images so as to allow accurate terrain modeling. In this study, we develop a real-time terrain storage generation and representation system including a nonground point database (PDB, ground mesh database (MDB, and texture database (TDB. A voxel-based flag map is proposed for incrementally registering large-scale point clouds in a terrain model in real time. We quantize the 3D point clouds into 3D grids of the flag map as a comparative table in order to remove the redundant points. We integrate the large-scale 3D point clouds into a nonground PDB and a node-based terrain mesh using the CPU. Subsequently, we program a graphics processing unit (GPU to generate the TDB by mapping the triangles in the terrain mesh onto the captured video images. Finally, we produce a nonground voxel map and a ground textured mesh as a terrain reconstruction result. Our proposed methods were tested in an outdoor environment. Our results show that the proposed system was able to rapidly generate terrain storage and provide high resolution terrain representation for mobile mapping services and a graphical user interface between remote operators and mobile robots.

  12. Urban boundary layer analysis in the complex coastal terrain of Bilbao using Enviro-HIRLAM

    Science.gov (United States)

    González-Aparicio, I.; Hidalgo, J.; Baklanov, A.; Korsholm, U.; Nuterman, R.; Mahura, A.; Santa-Coloma, O.

    2013-08-01

    This study analyses the atmospheric boundary layer over the Bilbao metropolitan area during summer (13-18 Jul 2009) and winter (20-29 Jan 2010) episodes using the Environment-High Resolution Limited Area Model (Enviro-HIRLAM) coupled with the building effect parameterisation (BEP). The main objectives of this study are: to evaluate the performance of the model to simulate the land-sea breezes over this complex terrain; to assess the simulations with the integration of an urban parameterisation in Enviro-HIRLAM and finally; and to analyse the urban-atmosphere interactions. Even if the hydrostraticity of the model is a limitation to simulate atmospheric flows over complex terrain, sensibility tests demonstrate that 2.4 km is the optimal horizontal resolution over Bilbao that allows at the same time: to obtain satisfactory reproducibility of the large-scale processes and to explore the urban effects at local scale. During the summer episode, a typical regime of diurnal sea breeze from the NW-N-NE direction and nocturnal valley breezes from the SE direction are observed over Bilbao. The urban heat island (UHI) phenomenon is developed in the city centre expanding to the suburbs from 22 to 10 local time (LT), covering an area of 130 km2. The maximum UHI intensity, 1 °C, is reached at the end of the night (5 LT), and it is advected 12 km towards the sea by the land breezes. The urban boundary layer (UBL) height amplitude varies from 100 (night time) to 1,360 m (at 14 LT). During the winter episode, the land breeze dominates the atmospheric diffusion during the day and night time. The maximum UHI intensity, 1.7 °C, is observed at 01 LT. It is spread and remained over the city covering an area of 160 km2, with a vertical extension of 33 m. The UBL reaches 780 m height at 16 LT the following day.

  13. Semi-automated extraction of longitudinal subglacial bedforms from digital terrain models - Two new methods

    Science.gov (United States)

    Jorge, Marco G.; Brennand, Tracy A.

    2017-07-01

    Relict drumlin and mega-scale glacial lineation (positive relief, longitudinal subglacial bedforms - LSBs) morphometry has been used as a proxy for paleo ice-sheet dynamics. LSB morphometric inventories have relied on manual mapping, which is slow and subjective and thus potentially difficult to reproduce. Automated methods are faster and reproducible, but previous methods for LSB semi-automated mapping have not been highly successful. Here, two new object-based methods for the semi-automated extraction of LSBs (footprints) from digital terrain models are compared in a test area in the Puget Lowland, Washington, USA. As segmentation procedures to create LSB-candidate objects, the normalized closed contour method relies on the contouring of a normalized local relief model addressing LSBs on slopes, and the landform elements mask method relies on the classification of landform elements derived from the digital terrain model. For identifying which LSB-candidate objects correspond to LSBs, both methods use the same LSB operational definition: a ruleset encapsulating expert knowledge, published morphometric data, and the morphometric range of LSBs in the study area. The normalized closed contour method was separately applied to four different local relief models, two computed in moving windows and two hydrology-based. Overall, the normalized closed contour method outperformed the landform elements mask method. The normalized closed contour method performed on a hydrological relief model from a multiple direction flow routing algorithm performed best. For an assessment of its transferability, the normalized closed contour method was evaluated on a second area, the Chautauqua drumlin field, Pennsylvania and New York, USA where it performed better than in the Puget Lowland. A broad comparison to previous methods suggests that the normalized relief closed contour method may be the most capable method to date, but more development is required.

  14. Visual Odometry for Planetary Exploration Rovers in Sandy Terrains

    Directory of Open Access Journals (Sweden)

    Linhui Li

    2013-05-01

    Full Text Available Abstract Visual odometry provides planetary exploration rovers with accurate knowledge of their position and orientation, which needs effective feature tracking results, especially in barren sandy terrains. In this paper, a stereovision based odometry algorithm is proposed for a lunar rover, which is composed of corner extraction, feature tracking and motion estimation. First, a morphology based image enhancement method is studied to guarantee enough corners are extracted. Second, a Random Sample Consensus (RANSAC algorithm is proposed to make a robust estimation of the fundamental matrix, which is the basic and critical part of feature matching and tracking. Then, the 6 degrees of freedom rover position and orientation is estimated by the RANSAC algorithm. Finally, experiments are performed in a simulated lunar surface environment using a prototype rover, which have confirmed the feasibility and effectiveness of the proposed method.

  15. Global multi-resolution terrain elevation data 2010 (GMTED2010)

    Science.gov (United States)

    Danielson, Jeffrey J.; Gesch, Dean B.

    2011-01-01

    In 1996, the U.S. Geological Survey (USGS) developed a global topographic elevation model designated as GTOPO30 at a horizontal resolution of 30 arc-seconds for the entire Earth. Because no single source of topographic information covered the entire land surface, GTOPO30 was derived from eight raster and vector sources that included a substantial amount of U.S. Defense Mapping Agency data. The quality of the elevation data in GTOPO30 varies widely; there are no spatially-referenced metadata, and the major topographic features such as ridgelines and valleys are not well represented. Despite its coarse resolution and limited attributes, GTOPO30 has been widely used for a variety of hydrological, climatological, and geomorphological applications as well as military applications, where a regional, continental, or global scale topographic model is required. These applications have ranged from delineating drainage networks and watersheds to using digital elevation data for the extraction of topographic structure and three-dimensional (3D) visualization exercises (Jenson and Domingue, 1988; Verdin and Greenlee, 1996; Lehner and others, 2008). Many of the fundamental geophysical processes active at the Earth's surface are controlled or strongly influenced by topography, thus the critical need for high-quality terrain data (Gesch, 1994). U.S. Department of Defense requirements for mission planning, geographic registration of remotely sensed imagery, terrain visualization, and map production are similarly dependent on global topographic data. Since the time GTOPO30 was completed, the availability of higher-quality elevation data over large geographic areas has improved markedly. New data sources include global Digital Terrain Elevation Data (DTEDRegistered) from the Shuttle Radar Topography Mission (SRTM), Canadian elevation data, and data from the Ice, Cloud, and land Elevation Satellite (ICESat). Given the widespread use of GTOPO30 and the equivalent 30-arc

  16. Sound Diffraction Modeling of Rotorcraft Noise Around Terrain

    Science.gov (United States)

    Stephenson, James H.; Sim, Ben W.; Chitta, Subhashini; Steinhoff, John

    2017-01-01

    A new computational technique, Wave Confinement (WC), is extended here to account for sound diffraction around arbitrary terrain. While diffraction around elementary scattering objects, such as a knife edge, single slit, disc, sphere, etc. has been studied for several decades, realistic environments still pose significant problems. This new technique is first validated against Sommerfeld's classical problem of diffraction due to a knife edge. This is followed by comparisons with diffraction over three-dimensional smooth obstacles, such as a disc and Gaussian hill. Finally, comparisons with flight test acoustics data measured behind a hill are also shown. Comparison between experiment and Wave Confinement prediction demonstrates that a Poisson spot occurred behind the isolated hill, resulting in significantly increased sound intensity near the center of the shadowed region.

  17. Predicting Wine Quality from Terrain Characteristics by Regression Trees

    Directory of Open Access Journals (Sweden)

    Reiner Schwarz

    1997-11-01

    Full Text Available On utilise une précédente étude cartographique sur les caractéristiques des terrains de l'espace du Rhinegau allemand. On essaye d'évaluer la qualité relative du Riesling d'après des facteurs de localisation à l'aide d'une classification et d'un arbre de régression (CART. La validité des résultats suppose que la qualité supplante la quantité, que le niveau des prix ou les méthodes de vinification ne sont pas pris en compte. L'étude montre que CART est un outil statistique valable, sans restriction quant à la nature des données.

  18. A high-accuracy map of global terrain elevations

    Science.gov (United States)

    Yamazaki, Dai; Ikeshima, Daiki; Tawatari, Ryunosuke; Yamaguchi, Tomohiro; O'Loughlin, Fiachra; Neal, Jeffery C.; Sampson, Christopher C.; Kanae, Shinjiro; Bates, Paul D.

    2017-06-01

    Spaceborne digital elevation models (DEMs) are a fundamental input for many geoscience studies, but they still include nonnegligible height errors. Here we introduce a high-accuracy global DEM at 3″ resolution ( 90 m at the equator) by eliminating major error components from existing DEMs. We separated absolute bias, stripe noise, speckle noise, and tree height bias using multiple satellite data sets and filtering techniques. After the error removal, land areas mapped with ±2 m or better vertical accuracy were increased from 39% to 58%. Significant improvements were found in flat regions where height errors larger than topography variability, and landscapes such as river networks and hill-valley structures, became clearly represented. We found the topography slope of previous DEMs was largely distorted in most of world major floodplains (e.g., Ganges, Nile, Niger, and Mekong) and swamp forests (e.g., Amazon, Congo, and Vasyugan). The newly developed DEM will enhance many geoscience applications which are terrain dependent.

  19. Nocturnal low-level jets: sporadic turbulence on complex terrain

    Science.gov (United States)

    Jimenez, M. A.; Cuxart, J.

    2009-04-01

    Under weak pressure gradient conditions and clear-sky nights the development of locally generated circulations is favourished, specially in complex terrain. As night advances, the layer close to the ground cools down and stably stratified conditions prevail, with weak and usually sporadic or intermittent turbulence. In this work this phenomena is studied through high-resolution mesoscale simulations that are verified with data from weather stations and satellite information. The chosen domain is the island of Majorca, located in the western Mediterranean sea. A large variety of circulations is observed in the three main basins of the island, with drainage flows and organization at the basin scale. These low-level jet structures occasionaly cause turbulent bursts and very efficient mixing in the vertical, leading to significant changes of the atmospheric conditions close to the ground.

  20. Terrain Considerations and Data Base Development for the Design and Testing of Devices to Detect Intruder-Induced Ground Motion

    Science.gov (United States)

    1978-05-01

    in the literature dealing with pavement design) *l6 The compression spring constant can have one of several shapes:’- (a) it can be linear; (b) it...H:od, and on the evaluation and •nalysis of the terrain data obtained from available literature sources, 16 field sites were considered and visited prior...northwest to the San Joaquin Hills on the southeast, a distance of 80 km; its width from the sea back to the Puente Hills varies from 24 km 2 to 32

  1. Interpolating atmospheric water vapor delay by incorporating terrain elevation information

    Science.gov (United States)

    Xu, W. B.; Li, Z. W.; Ding, X. L.; Zhu, J. J.

    2011-09-01

    In radio signal-based observing systems, such as Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR), the water vapor in the atmosphere will cause delays during the signal transmission. Such delays vary significantly with terrain elevation. In the case when atmospheric delays are to be eliminated from the measured raw signals, spatial interpolators may be needed. By taking advantage of available terrain elevation information during spatial interpolation process, the accuracy of the atmospheric delay mapping can be considerably improved. This paper first reviews three elevation-dependent water vapor interpolation models, i.e., the Best Linear Unbiased Estimator in combination with the water vapor Height Scaling Model (BLUE + HSM), the Best Linear Unbiased Estimator coupled with the Elevation-dependent Covariance Model (BLUE + ECM), and the Simple Kriging with varying local means based on the Baby semi-empirical model (SKlm + Baby for short). A revision to the SKlm + Baby model is then presented, where the Onn water vapor delay model is adopted to substitute the inaccurate Baby semi-empirical model (SKlm + Onn for short). Experiments with the zenith wet delays obtained through the GPS observations from the Southern California Integrated GPS Network (SCIGN) demonstrate that the SKlm + Onn model outperforms the other three. The RMS of SKlm + Onn is only 0.55 cm, while those of BLUE + HSM, BLUE + ECM and SKlm + Baby amount to 1.11, 1.49 and 0.77 cm, respectively. The proposed SKlm + Onn model therefore represents an improvement of 29-63% over the other known models.

  2. Stability Impact on Wake Development in Moderately Complex Terrain

    Science.gov (United States)

    Infield, D.; Zorzi, G.

    2017-05-01

    This paper uses a year of SCADA data from Whitelee Wind Farm near Glasgow to investigate wind turbine wake development in moderately complex terrain. Atmospheric stability measurements in terms of Richardson number from a met mast at an adjoining site have been obtained and used to assess the impact of stability on wake development. Considerable filtering of these data has been undertaken to ensure that all turbines are working normally and are well aligned with the wind direction. A group of six wind turbines, more or less in a line, have been selected for analysis, and winds within a 2 degree direction sector about this line are used to ensure, as far as possible, that all the turbines investigated are fully immersed in the wake/s of the upstream turbine/s. Results show how the terrain effects combine with the wake effects, with both being of comparable importance for the site in question. Comparison has been made with results from two commercial CFD codes for neutral stability, and reasonable agreement is demonstrated. Richardson number has been plotted against wind shear and turbulence intensity at a met mast on the wind farm that for the selected wind direction is not in the wake of any turbines. Good correlations are found indicating that the Richardson numbers obtained are reliable. The filtered data used for wake analysis were split according to Richardson number into two groups representing slightly stable to neutral, and unstable conditions. Very little difference in wake development is apparent. A greater difference can be observed when the data are separated simply by turbulence intensity, suggesting that, although turbulence intensity is correlated with stability, of the two it is the parameter that most directly impacts on wake development through mixing of ambient and wake flows.

  3. Pacing during an ultramarathon running event in hilly terrain

    Directory of Open Access Journals (Sweden)

    Hugo A. Kerhervé

    2016-10-01

    Full Text Available Purpose The dynamics of speed selection as a function of distance, or pacing, are used in recreational, competitive, and scientific research situations as an indirect measure of the psycho-physiological status of an individual. The purpose of this study was to determine pacing on level, uphill and downhill sections of participants in a long (>80 km ultramarathon performed on trails in hilly terrain. Methods Fifteen ultramarathon runners competed in a  173 km event (five finished at  103 km carrying a Global-Positioning System (GPS device. Using the GPS data, we determined the speed, relative to average total speed, in level (LEV, uphill (UH and downhill (DH gradient categories as a function of total distance, as well as the correlation between overall performance and speed variability, speed loss, and total time stopped. Results There were no significant differences in normality, variances or means in the relative speed in 173-km and 103-km participants. Relative speed decreased in LEV, UH and DH. The main component of speed loss occurred between 5% and 50% of the event distance in LEV, and between 5% and 95% in UH and DH. There were no significant correlations between overall performance and speed loss, the variability of speed, or total time stopped. Conclusions Positive pacing was observed at all gradients, with the main component of speed loss occurring earlier (mixed pacing in LEV compared to UH and DH. A speed reserve (increased speed in the last section was observed in LEV and UH. The decrease in speed and variability of speed were more important in LEV and DH than in UH. The absence of a significant correlation between overall performance and descriptors of pacing is novel and indicates that pacing in ultramarathons in trails and hilly terrain differs to other types of running events.

  4. Numerical simulation of radiation fog in complex terrain

    Science.gov (United States)

    Zhang, X.; Musson-Genon, L.; Carissimo, B.; Dupont, E.

    2009-09-01

    The interest for micro-scale modeling of the atmosphere is growing for environmental applications related, for example, to energy production, transport and urban development. The turbulence in the stable layers where pollutant dispersion is low and can lead to strong pollution events. This could be further complicated by the presence of clouds or fog and is specifically difficult in urban or industrial area due to the presence of buildings. In this context, radiation fog formation and dissipation over complex terrain were therefore investigated with a state-of-the-art model. This study is divided into two phases. The first phase is a pilot stage, which consist of employing a database from the ParisFog campaign which took place in the south of Paris during winter 2006-07 to assess the ability of the cloud model to reproduce the detailed structure of radiation fog. The second phase use the validated model for the study of influence of complex terrain on fog evolution. Special attention is given to the detailed and complete simulations and validation technique used is to compare the simulated results using the 3D cloud model of computational fluid dynamical software Code_Saturne with one of the best collected in situ data during the ParisFog campaign. Several dynamical, microphysical parameterizations and simulation conditions have been described. The resulting 3D cloud model runs at a horizontal resolution of 30 m and a vertical resolution comparable to the 1D model. First results look very promising and are able to reproduce the spatial distribution of fog. The analysis of the behavior of the different parameterized physical processes suggests that the subtle balance between the various processes is achieved.

  5. LEBANESE SOIL AND TERRAIN UNITES DELINEATION BASED ON DIGITAL ELEVATION MODELS

    Directory of Open Access Journals (Sweden)

    Jean A. Doumit

    2015-01-01

    Full Text Available The Soil and Terrain digital database (SOTER stores attribute data on landform and soils, the United Nations Environmental Program (UNEP create a soil and terrain digital database with a global coverage at a spatial resolution of one kilometer approximately. For a little country as Lebanon such data with a very low resolution cannot be useful, Until recently, only manual methods were used to delineate SOTER (SOil and TERrain Digital Database Units [21]. Theaimofourstudyisto apply aquantitativemethodtoderive terrain classes that match the physiography SOTER of the Lebanese territory at regional scale. According to SRTMdigital elevation model todefinetheSOTERTerrainUnit: hypsometry, slope, reliefintensity and stream density. Several GIS techniques were employed to translate the SOTER mapping concept. The four features are combined and vectorized to achieve the delineation of the SOTER Terrain unit’s map at a spatial precision of 90 meters.

  6. Landing Control of Foot with Springs for Walking Robots on Rough Terrain

    Directory of Open Access Journals (Sweden)

    Moyuru Yamada

    2009-09-01

    Full Text Available Landing control is one of the important issues for biped walking robot, because robots are expected to walk on not only known flat surfaces but also unknown and uneven terrain for working at various fields. This paper presents a new controller design for a robotic foot to land on unknown terrain. The robotic foot considered in this study equips springs to reduce the impact force at the foot landing. There are two objectives in the landing control; achieving the desired ground reaction force and positioning the foot on unknown terrain. To achieve these two objectives simultaneously by adjusting the foot position, we propose a PI force controller with a desired foot position, which guarantees the robust stability of control system with respect to terrain variance, and exact positioning of the foot to unknown terrain. Simulation results using the Open Dynamics Engine demonstrate the effectiveness of the proposed controller.

  7. Experimental Setup to Assess Blast and Penetration-Induced Secondary Debris in a Military Operations in Urban Terrain (MOUT) Environment

    Science.gov (United States)

    2015-11-01

    in a Military Operations in Urban Terrain (MOUT) Environment by Paul S Duvall Approved for public release; distribution...Research Laboratory Experimental Setup to Assess Blast and Penetration-Induced Secondary Debris in a Military Operations in Urban Terrain...Induced Secondary Debris in a Military Operations in Urban Terrain (MOUT) Environment 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  8. A real-time airborne terrain aided inertial navigation system and its performance analysis

    Science.gov (United States)

    Zhang, Q. Q.; Zhao, L.; Zhou, J. H.; Wang, B. H.; Zhang, Y. P.

    2017-12-01

    The current terrain aided navigation system has a shortcoming that it depends on terrain feature, so we need to select the terrain matching area and plan the flight path according to the flight mission in advance. In this paper, we present a real-time airborne terrain aided inertial navigation system. The system can plan and select the matching area online according to the heading angle and estimated position errors during aircraft flight, and adopt the appropriate terrain-aided navigation algorithm for different terrain areas and flight conditions. So it can ensure the positioning accuracy and improve the ability of carrier to maneuver at the same time. In order to verify the performance of the system, a flight simulation experiment and a real flight test are carried out, and we conduct a research on the performance of matching area planning and real-time positioning. The tests results show that the system can improve the ability of carrier to maneuver and the performance of real-time positioning. In addition, the system has a higher positioning accuracy and reliability than traditional TERCOM and SITAN methods. The position error is less than 50 m in acquisition mode and less than 18 m in tracking mode with the terrain elevation map of 25 m-resolution.

  9. Convective boundary layer heights over mountainous terrain – A review of concepts –

    Directory of Open Access Journals (Sweden)

    Stephan F.J. De Wekker

    2015-12-01

    Full Text Available Mountainous terrain exerts an important influence on the Earth's atmosphere and affects atmospheric transport and mixing at a wide range of temporal and spatial scales. The vertical scale of this transport and mixing is determined by the height of the atmospheric boundary layer, which is therefore an important parameter in air pollution studies, weather forecasting, climate modeling, and many other applications. It is recognized that the spatio-temporal structure of the daytime convective boundary layer (CBL height is strongly modified and more complex in hilly and mountainous terrain compared to flat terrain. While the CBL over flat terrain is mostly dominated by turbulent convection, advection from multi-scale thermally driven flows plays an important role for the CBL evolution over mountainous terrain. However, detailed observations of the CBL structure and understanding of the underlying processes are still limited. Characteristics of CBL heights in mountainous terrain are reviewed for dry, convective conditions. CBLs in valleys and basins, where hazardous accumulation of pollutants is of particular concern, are relatively well-understood compared to CBLs over slopes, ridges, or mountain peaks. Interests in the initiation of shallow and deep convection, and of budgets and long-range transport of air pollutants and trace gases, have triggered some recent studies on terrain induced exchange processes between the CBL and the overlying atmosphere. These studies have helped to gain more insight into CBL structure over complex mountainous terrain, but also show that the universal definition of CBL height over mountains remains an unresolved issue. The review summarizes the progress that has been made in documenting and understanding spatio-temporal behavior of CBL heights in mountainous terrain and concludes with a discussion of open research questions and opportunities for future research.

  10. Convective boundary layer heights over mountainous terrain - A review of concepts -

    Science.gov (United States)

    De Wekker, Stephan; Kossmann, Meinolf

    2015-12-01

    Mountainous terrain exerts an important influence on the Earth's atmosphere and affects atmospheric transport and mixing at a wide range of temporal and spatial scales. The vertical scale of this transport and mixing is determined by the height of the atmospheric boundary layer, which is therefore an important parameter in air pollution studies, weather forecasting, climate modeling, and many other applications. It is recognized that the spatio-temporal structure of the daytime convective boundary layer (CBL) height is strongly modified and more complex in hilly and mountainous terrain compared to flat terrain. While the CBL over flat terrain is mostly dominated by turbulent convection, advection from multi-scale thermally driven flows plays an important role for the CBL evolution over mountainous terrain. However, detailed observations of the CBL structure and understanding of the underlying processes are still limited. Characteristics of CBL heights in mountainous terrain are reviewed for dry, convective conditions. CBLs in valleys and basins, where hazardous accumulation of pollutants is of particular concern, are relatively well-understood compared to CBLs over slopes, ridges, or mountain peaks. Interests in the initiation of shallow and deep convection, and of budgets and long-range transport of air pollutants and trace gases, have triggered some recent studies on terrain induced exchange processes between the CBL and the overlying atmosphere. These studies have helped to gain more insight into CBL structure over complex mountainous terrain, but also show that the universal definition of CBL height over mountains remains an unresolved issue. The review summarizes the progress that has been made in documenting and understanding spatio-temporal behavior of CBL heights in mountainous terrain and concludes with a discussion of open research questions and opportunities for future research.

  11. Delineation of Fractured Aquifer Using Numerical Analysis (Factor of Resistivity Data in a Granite Terrain

    Directory of Open Access Journals (Sweden)

    Rolland Andrade

    2014-01-01

    Full Text Available In hard rock terrain, fractured aquifers comprise the major source of groundwater availability where the phreatic aquifer is desaturated. Identification of fracture zones in hard rock terrain and potential groundwater source delineation had been a perennial problem in hydrology. The purpose of this paper is to highlight the study over a small watershed area, in a granite terrain, wherein an attempt was made to delineate and map the fractured aquifer using numerical (factor analysis of the conventional vertical electrical sounding data, which was obscure in curve matching technique. This numerical approach in concatenation with resistivity imaging or other techniques would prove to be an effective tool in groundwater exploration.

  12. A vision-based terrain morphology estimation model inspired by the avian hippocampus

    Directory of Open Access Journals (Sweden)

    John Oyekan

    2015-04-01

    In this paper, we take inspiration from the avian hippocampus and develop a preliminary model for estimating a terrain׳s morphology using visually detected features on the terrain. This could then be used to localise a portable micro-UAV during a demining task for humanitarian purposes in third world countries affected by buried land mines from previous wars. Our goal is that in future, the presented model and algorithm in this work would enable effective coverage of an affected area using the visual information obtained from the environment.

  13. Influence of sub-kilometer precipitation datasets on simulated snowpack and glacier winter balance in alpine terrain.

    Science.gov (United States)

    Vionnet, Vincent; Six, Delphine; Auger, Ludovic; Lafaysse, Matthieu; Quéno, Louis; Réveillet, Marion; Dombrowski-Etchevers, Ingrid; Thibert, Emmanuel; Dumont, Marie

    2017-04-01

    Capturing spatial and temporal variabilities of meteorological conditions at fine scale is necessary for modelling snowpack and glacier winter mass balance in alpine terrain. In particular, precipitation amount and phase are strongly influenced by the complex topography. In this study, we assess the impact of three sub-kilometer precipitation datasets (rainfall and snowfall) on distributed simulations of snowpack and glacier winter mass balance with the detailed snowpack model Crocus for winter 2011-2012. The different precipitation datasets at 500-m grid spacing over part of the French Alps (200*200 km2 area) are coming either from (i) the SAFRAN precipitation analysis specially developed for alpine terrain, or from (ii) operational outputs of the atmospheric model AROME at 2.5-km grid spacing downscaled to 500 m with fixed lapse rate or from (iii) a version of the atmospheric model AROME at 500-m grid spacing. Others atmospherics forcings (air temperature and humidity, incoming longwave and shortwave radiation, wind speed) are taken from the AROME simulations at 500-m grid spacing. These atmospheric forcings are firstly compared against a network of automatic weather stations. Results are analysed with respect to station location (valley, mid- and high-altitude). The spatial pattern of seasonal snowfall and its dependency with elevation is then analysed for the different precipitation datasets. Large differences between SAFRAN and the two versions of AROME are found at high-altitude. Finally, results of Crocus snowpack simulations are evaluated against (i) punctual in-situ measurements of snow depth and snow water equivalent, and (ii) maps of snow covered areas retrieved from optical satellite data (MODIS). Measurements of winter accumulation of six glaciers of the French Alps are also used and provide very valuable information on precipitation at high-altitude where the conventional observation network is scarce. This study illustrates the potential and

  14. Terrain and drift influences on snow surface aerodynamics (Invited)

    Science.gov (United States)

    Clifton, A.; Leonard, K. C.; Manes, C.; Lehning, M.

    2010-12-01

    It has long been recognised in many branches of aeolian research that the process of sediment transport by the wind alters the surface aerodynamics. This effect is less clear over snow surfaces, particularly because of the difficulty of accurately identifying the contribution of surface topography and surface change. We present a synopsis of data from a series of experiments carried out over the last 5 years in a wind tunnel, in a test site in the European Alps and in Antarctica. This data covers both snow surface aerodynamic properties and drift activity and required the development of laboratory and field techniques to measure and better understand snow surface aerodynamics and drift activity. Our data allow the different contributions of snow drift and terrain to be separated, revealing that in some situations drift may significantly modify the apparent aerodynamic properties of the underlying surface. This effect is similar to that seen for soil or sand transport. A comparison with established land-surface classification methods of predicting roughness length shows that these effects can be important when assessing wind fields over snow.

  15. Unevenness Point Descriptor for Terrain Analysis in Mobile Robot Applications

    Directory of Open Access Journals (Sweden)

    Mauro Bellone

    2013-07-01

    Full Text Available In recent years, the use of imaging sensors that produce a three-dimensional representation of the environment has become an efficient solution to increase the degree of perception of autonomous mobile robots. Accurate and dense 3D point clouds can be generated from traditional stereo systems and laser scanners or from the new generation of RGB-D cameras, representing a versatile, reliable and cost-effective solution that is rapidly gaining interest within the robotics community. For autonomous mobile robots, it is critical to assess the traversability of the surrounding environment, especially when driving across natural terrain. In this paper, a novel approach to detect traversable and non-traversable regions of the environment from a depth image is presented that could enhance mobility and safety through integration with localization, control and planning methods. The proposed algorithm is based on the analysis of the normal vector of a surface obtained through Principal Component Analysis and it leads to the definition of a novel, so defined, Unevenness Point Descriptor. Experimental results, obtained with vehicles operating in indoor and outdoor environments, are presented to validate this approach.

  16. Detecting Terrain Stoniness From Airborne Laser Scanning Data †

    Directory of Open Access Journals (Sweden)

    Paavo Nevalainen

    2016-08-01

    Full Text Available Three methods to estimate the presence of ground surface stones from publicly available Airborne Laser Scanning (ALS point clouds are presented. The first method approximates the local curvature by local linear multi-scale fitting, and the second method uses Discrete-Differential Gaussian curvature based on the ground surface triangulation. The third baseline method applies Laplace filtering to Digital Elevation Model (DEM in a 2 m regular grid data. All methods produce an approximate Gaussian curvature distribution which is then vectorized and classified by logistic regression. Two training data sets consisted of 88 and 674 polygons of mass-flow deposits, respectively. The locality of the polygon samples is a sparse canopy boreal forest, where the density of ALS ground returns is sufficiently high to reveal information about terrain micro-topography. The surface stoniness of each polygon sample was categorized for supervised learning by expert observation on the site. The leave-pair-out (L2O cross-validation of the local linear fit method results in the area under curve A U C = 0 . 74 and A U C = 0 . 85 on two data sets, respectively. This performance can be expected to suit real world applications such as detecting coarse-grained sediments for infrastructure construction. A wall-to-wall predictor based on the study was demonstrated.

  17. Detecting changes in terrain using unmanned aerial vehicles

    Science.gov (United States)

    Rahman, Zia-ur; Hines, Glenn D.; Logan, Michael J.

    2005-05-01

    In recent years, small unmanned aerial vehicles (UAVs) have been used for more than the thrill they bring to model airplane enthusiasts. Their flexibility and low cost have made them a viable option for low-altitude reconnaissance. In a recent effort, we acquired video data from a small UAV during several passes over the same flight path. The objective of the exercise was to determine if objects had been added to the terrain along the flight path between flight passes. Several issues accrue to this simple-sounding problem: (1) lighting variations may cause false detection of objects because of changes in shadow orientation and strength between passes; (2) variations in the flight path due to wind-speed, and heading change may cause misalignment of gross features making the task of detecting changes between the frames very difficult; and (3) changes in the aircraft orientation and altitude lead to a change in size of the features from frame-to-frame making a comparison difficult. In this paper, we discuss our efforts to perform this change detection, and the lessons that we learned from this exercise.

  18. Complex terrain experiments in the New European Wind Atlas

    Science.gov (United States)

    Angelou, N.; Callies, D.; Cantero, E.; Arroyo, R. Chávez; Courtney, M.; Cuxart, J.; Dellwik, E.; Gottschall, J.; Ivanell, S.; Kühn, P.; Lea, G.; Matos, J. C.; Palma, J. M. L. M.; Peña, A.; Rodrigo, J. Sanz; Söderberg, S.; Vasiljevic, N.; Rodrigues, C. Veiga

    2017-01-01

    The New European Wind Atlas project will create a freely accessible wind atlas covering Europe and Turkey, develop the model chain to create the atlas and perform a series of experiments on flow in many different kinds of complex terrain to validate the models. This paper describes the experiments of which some are nearly completed while others are in the planning stage. All experiments focus on the flow properties that are relevant for wind turbines, so the main focus is the mean flow and the turbulence at heights between 40 and 300 m. Also extreme winds, wind shear and veer, and diurnal and seasonal variations of the wind are of interest. Common to all the experiments is the use of Doppler lidar systems to supplement and in some cases replace completely meteorological towers. Many of the lidars will be equipped with scan heads that will allow for arbitrary scan patterns by several synchronized systems. Two pilot experiments, one in Portugal and one in Germany, show the value of using multiple synchronized, scanning lidar, both in terms of the accuracy of the measurements and the atmospheric physical processes that can be studied. The experimental data will be used for validation of atmospheric flow models and will by the end of the project be freely available. This article is part of the themed issue ‘Wind energy in complex terrains’. PMID:28265025

  19. Terrain modelling and motion planning for an autonomous exploration rover

    Science.gov (United States)

    Richard, F.; Benoliel, S.; Faugeras, O.; Grandjean, P.; Hayard, M.; Simeon, T.

    1994-01-01

    To assess the feasibility of planetary exploration missions using rovers, the French national agency CNES, with a consortium of European laboratories and industrial concerns, has initiated the Eureka project, 'Illustration of an Autonomous Robot for the Exploration of Space' (IARES). IARES is a demonstrator composed of a rover and a ground station, linked by telemetry and telecommand. It is aimed at verifying, on earth, robotic concepts developed by the RISP group of French laboratories (LAAS, INRIA, CERT, LETI) to perform scientific missions such as autonomous terrain sample collecting over large areas. To cope with the actual needs of planet exploration, IARES suitability is assessed through constraints on limited bandwidth, time delay and on-board resources. This autonomy relies heavily on robust onboard trajectory generation capabilities. This paper presents the main functions of the IARES navigation sub-system and shows how they are combined to allow movement in Mars-like environments. Section 2 gives an overall description of the IARES system. Section 3 details the functions of the Navigation sub-system, and finally, section 4 illustrates with a simple example the use of these functions.

  20. Aerodynamic performances of cruise missile flying above local terrain

    Science.gov (United States)

    Ahmad, A.; Saad, M. R.; Che Idris, A.; Rahman, M. R. A.; Sujipto, S.

    2016-10-01

    Cruise missile can be classified as a smart bomb and also Unmanned Aerial Vehicle (UAV) due to its ability to move and manoeuvre by itself without a pilot. Cruise missile flies in constant velocity in cruising stage. Malaysia is one of the consumers of cruise missiles that are imported from other nations, which can have distinct geographic factors including their local terrains compared to Malaysia. Some of the aerodynamic performances of missile such as drag and lift coefficients can be affected by the local geographic conditions in Malaysia, which is different from the origin nation. Therefore, a detailed study must be done to get aerodynamic performance of cruise missiles that operate in Malaysia. The effect of aerodynamic angles such as angle of attack and side slip can be used to investigate the aerodynamic performances of cruise missile. Hence, subsonic wind tunnel testings were conducted to obtain the aerodynamic performances of the missile at various angle of attack and sideslip angles. Smoke visualization was also performed to visualize the behaviour of flow separation. The optimum angle of attack found was at α=21° and side slip, β=10° for optimum pitching and yawing motion of cruise missile.

  1. Geometrical properties of a discontinuity network in gneissic rock, a case study in high alpine terrain

    Science.gov (United States)

    Koppensteiner, Matthias; Zangerl, Christian

    2017-04-01

    For the purposes of estimating slope stability and investigating landslide formation processes, it is indispensable to obtain information about the discontinuity properties of the rock mass. These properties control failure processes, deformation behaviour and groundwater flow. Scanline measurements represent a systematic surveying method, however they make certain demands in case of natural outcorps in a high alpine terrain. The performance of the scanline method is tested and the thereby obtained and evaluated data is compared to findings from other studies. An area of a well exposed, fractured rock mass composed of granodioritic gneisses in the Oetztal-Stubai crytalline basement of the Alps (Austria) has been chosen to perform the investigations. Eight scanlines have been measured on a single hillside with varying lengths between 8 and 30 meters. The orientations of the scanlines have been varied in order to minimize the sampling bias associated with the angle between the scanlines and the intersected discontinuities. For every intersecting discontinuity at a certain tape length, the orientation, the trace length and the terminations of the trace have been recorded. Primarily, the discontinuity data from all scanlines have been analyzed with the software package Dips (Rocscience, 1989) in order to determine their allocation in sets. For the evaluation of the spacing and trace length properties, two scripts have been developed in the language Matlab (The MathWorks, 1984) to faciliate setwise processing of the entire dataset. Variation of the scanline directions and lengths returned homogeneous sample sizes for the individual discontinuity sets. Both, normal spacings and trace lengths show negative exponential distributions for all sets. A comparison of four different methods to estimate trace lengths show that the result is highly dependent on the chosen method itself. However, when the relation of the results for the respective sets within one of the methods is

  2. Rapid Traversability Assessment in 2.5D Grid-based Map on Rough Terrain

    Directory of Open Access Journals (Sweden)

    Yi Huang

    2008-11-01

    Full Text Available This paper presents a rapid traversability assessment approach based on an extended 2.5D grid-based representaion of the rough terrain. Stereo vision system is used to perceive the environment surrounding robot. Conventional 2D, 3D and other 2.5D grid maps determine the traversability indices of the grids directly from the sensor feedback, while our approach attempts to address the indices of terrain from multiple grids instead. By analyzing the properties of multiple grids that the robot is to traverse, passable grids are distinguished, which also takes the robot's size into account. Fuzzy logic framework is applied to extract traversabiltiy indices from the terrain characteristics. A soccer robot equipped with a stereo vision system is adopted for experiments. The results show that our map is capable of speeding the process of traversability assessment and providing an autonomous mobile robot with a appropriate representation of 3D uneven terrain profile.

  3. TERRAIN DATA, CITY OF SOUTH LAKE TAHOE, EL DORADO COUNTY, CA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

  4. TERRAIN submission for Rock River Watershed Risk Map, Walworth County Portion

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. DCS Terrain Submission for City of Scappoose PAL, Columbia County OR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  6. Adaptive Pulsed Laser Line Extraction for Terrain Reconstruction using a Dynamic Vision Sensor

    Directory of Open Access Journals (Sweden)

    Christian eBrandli

    2014-01-01

    Full Text Available Mobile robots need to know the terrain in which they are moving for path planning and obstacle avoidance. This paper proposes the combination of a bio-inspired, redundancy-suppressing dynamic vision sensor with a pulsed line laser to allow fast terrain reconstruction. A stable laser stripe extraction is achieved by exploiting the sensor’s ability to capture the temporal dynamics in a scene. An adaptive temporal filter for the sensor output allows a reliable reconstruction of 3D terrain surfaces. Laser stripe extractions up to pulsing frequencies of 500Hz were achieved using a line laser of 3mW at a distance of 45cm using an event-based algorithm that exploits the sparseness of the sensor output. As a proof of concept, unstructured rapid prototype terrain samples have been successfully reconstructed with an accuracy of 2mm.

  7. Seasonal variation of wind direction fluctuations vs Pasquill stabilities in complex terrain

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.; Murthy, K.P.R.V.

    The authors have studied the seasonal variation of sigma theta (the standard deviation of wind direction fluctuations) vs Pasquill stabilities over complex terrain. It is found that the values of sigma theta are quite high in the month of April...

  8. DCS Terrain Submission for Sauk County, Wisconsin USA (Baraboo River Project)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. DCS Terrain Submission for Vernon County, Wisconsin USA (Baraboo River Project)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. Quality analysis of digital terrain models for the test area Zlatibor

    Directory of Open Access Journals (Sweden)

    Bajat Branislav

    2003-01-01

    Full Text Available Digital terrain models (DTM have recently become products which substitute standard methods for the terrain relief presentation. As a part of a Geographic Information Systems (GIS they represent not only a data base related to heights that are used for terrain visualization by the means of interpolation routines for the generation of contours, or terrain presentation by the 3D meshes, but also a useful data base in many GIS and other applications. Numerous users of DTMs should also be supplied with information of DTM quality. This is obtained by the statistical analysis of residuals between generated height and heights of the control points called ground truth. The results of this analysis might be compulsorily part of metadata base for all DTMs products.

  11. Wind Erosion of Layered Sediments on Mars, and the Role of Terrain

    Science.gov (United States)

    Steele, L. J.; Kite, E. S.; Michaels, T. I.

    2017-10-01

    Most sedimentary rocks on Mars exist as mounds in craters and canyons. To investigate the role of terrain in wind erosion, and the formation and evolution of these mounds, we combine mesoscale model output with a landscape evolution model.

  12. Laboratory simulations of the atmospheric mixed layer in flow over complex terrain

    Data.gov (United States)

    U.S. Environmental Protection Agency — A laboratory study of the influence of complex terrain on the interface between a well-mixed boundary layer and an elevated stratified layer was conducted in the...

  13. Pitted terrains around Marcia crater on Vesta: strong eucritic absorptions and their implications

    Science.gov (United States)

    Giebner, T.; Otto, K.; Jaumann, R.; Schröder, S. E.; Krohn, K.; Matz, K.-D.; Stephan, K.; Preusker, F.; Roatsch, T.

    2017-09-01

    On the asteroid Vesta, we found that some of the pitted terrains around the crater Marcia exhibit strong eucritic-like absorption features and are spectrally distinct from their immediate surrounding.

  14. DCS Terrain Submission for City of Washougal PAL, Clark County WA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  15. VBMP Digital Terrain Models - 2006/2007 (VA State Plane South)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

  16. Latent heat flux measurements over complex terrain by airborne water vapour and wind lidars

    National Research Council Canada - National Science Library

    Kiemle, Christoph; Wirth, Martin; Fix, Andreas; Rahm, Stephan; Corsmeier, Ulrich; Di Girolamo, Paolo

    2011-01-01

    Vertical profiles of the latent heat flux in a convective boundary layer (CBL) are obtained for the first time over complex terrain with airborne water vapour differential absorption lidar and Doppler wind lidar...

  17. TERRAIN, WAYNE COUNTY, MI CITY OF ROMULUS 10-05-2466P PMR, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. DCS Terrain Submission for City of Kelso PAL, Cowlitz County WA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  19. Ames Stereo Pipeline and LROC ASU Digital Terrain Model (DTM) Comparison

    Science.gov (United States)

    Brown, H. M.; Awumah, A. A.; Henriksen, M. R.; Manheim, M. R.; Cisneros, E.; Wagner, R. V.; Robinson, M. S.

    2017-06-01

    Comparison between NASA Ames Stereo Pipeline (ASP) and ASU LROC teams digital terrain model (DTM) products made from the same NAC stereo pairs. Using absolute, relative, and qualitative measurements, we provide recommendations for DTM product use.

  20. I/O-Efficient Computation of Water Flow Across a Terrain

    DEFF Research Database (Denmark)

    Arge, Lars Allan; Revsbæk, Morten; Zeh, Norbert

    2010-01-01

    Consider rain falling at a uniform rate onto a terrain T represented as a triangular irregular network. Over time, water collects in the basins of T, forming lakes that spill into adjacent basins. Our goal is to compute, for each terrain vertex, the time this vertex is flooded (covered by water......). We present an I/O-efficient algorithm that solves this problem using O(sort(X) log (X/M) + sort(N)) I/Os, where N is the number of terrain vertices, X is the number of pits of the terrain, sort(N) is the cost of sorting N data items, and M is the size of the computer's main memory. Our algorithm...

  1. DCS Terrain Submission for City of Longview PAL, Cowlitz County WA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  2. Path Planning Software and Graphics Interface for an Autonomous Vehicle, Accounting for Terrain Features

    National Research Council Canada - National Science Library

    Hurezeanu, Vlad

    2000-01-01

    .... This vehicle performs tasks to include surveying fields, laying mines, and teleoperation. The capability of the vehicle will be increased if its supporting software plans paths that take into account the terrain features...

  3. TERRAIN, Lake county, Illinois, USA-- BOGUS METADATA SEE NON-FEMA PROFILE METADATA PROVIDED BY VENDOR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  4. Pitted Terrain on Vesta and Implications for the Presence of Volatiles

    Science.gov (United States)

    Denevi, B. W.; Blewett, D. T.; Buczkowski, D. L.; Capaccioni, F.; Capria, M. T.; De Sanctis, M. C.; Garry, W. B.; Gaskell, R. W.; Le Corre, L.; Li, J.-Y.; Marchi, S.; McCoy, T. J.; Nathues, A.; O'Brien, D. P.; Petro, N. E.; Pieters, C. M.; Preusker, F.; Raymond, C. A.; Reddy, V.; Russell, C. T.; Schenk, P.; Scully, J. E. C.; Sunshine, J. M.; Tosi, F.; Williams, D. A.; Wyrick, D.

    2012-10-01

    We investigated the origin of unusual pitted terrain on asteroid Vesta, revealed in images from the Dawn spacecraft. Pitted terrain is characterized by irregular rimless depressions found in and around several impact craters, with a distinct morphology not observed on other airless bodies. Similar terrain is associated with numerous martian craters, where pits are thought to form through degassing of volatile-bearing material heated by the impact. Pitted terrain on Vesta may have formed in a similar manner, which indicates that portions of the surface contain a relatively large volatile component. Exogenic materials, such as water-rich carbonaceous chondrites, may be the source of volatiles, suggesting that impactor materials are preserved locally in relatively high abundance on Vesta and that impactor composition has played an important role in shaping the asteroid’s geology.

  5. La recherche sur le terrain ouvre des horizons au Vietnam | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Vivre les réalités de la recherche sur le terrain voilà ce que Claire Le Barbenchon, titulaire d'une bourse de recherche du CRDI en 2015, se remémore avec affection. « La recherche sur le terrain était une toute nouvelle expérience, mentionne-t-elle, et ce dans un pays encore inexploré pour moi : le Vietnam. »

  6. Proposal of a personal mobility vehicle capable of traversing rough terrain.

    Science.gov (United States)

    Nakajima, Shuro

    2014-05-01

    Personal mobility vehicles (PMVs) are now being actively developed. Most PMVs are wheel-driven, a mode of transport notable for its efficiency. However, such vehicles tend to have little mobility over rough terrain. We propose a new type of PMV, a vehicle that traverses relatively smooth terrain by wheel but is capable of negotiating rough terrain by using its wheel mechanisms as legs. The PMV we propose is intended to provide its user with a degree of outdoor mobility in daily urban life, say when going to a neighbourhood shop or simply taking a stroll. We do not consider elevators and other infrastructural elements that should be barrier-free, but rather focus on unimproved terrains that act as barriers to transport; for example, the steps that often act as de facto boundaries around building entrances. We developed a new type of PMV and implemented a new algorithm to realize the capability to move on rough terrain. We experimentally compared the capability of a commercially available PMV and the developed PMV. Through an experiment involving the traversing of a representative terrain and a comparative experiment using a stock PMV, we demonstrated the features of the proposed PMV. We developed a single-seat personal mobility vehicle, the RT-Mover PType 3, which is capable of traversing steps and other unimproved terrain often found within an urban environment. RT-Mover PType 3 can handle oblique slopes and other terrain that can be quite difficult to negotiate with a conventional electric wheelchair, thus enabling individuals with impaired mobility to move freely about urban environments. The current vehicle is primarily intended for the active elderly and other individuals in fairly good health, although, through further research and development, we do hope to extend its usefulness to those with substantial mobility impairments.

  7. Slip-based terrain estimation with a skid-steer vehicle

    Science.gov (United States)

    Reina, Giulio; Galati, Rocco

    2016-10-01

    In this paper, a novel approach for online terrain characterisation is presented using a skid-steer vehicle. In the context of this research, terrain characterisation refers to the estimation of physical parameters that affects the terrain ability to support vehicular motion. These parameters are inferred from the modelling of the kinematic and dynamic behaviour of a skid-steer vehicle that reveals the underlying relationships governing the vehicle-terrain interaction. The concept of slip track is introduced as a measure of the slippage experienced by the vehicle during turning motion. The proposed terrain estimation system includes common onboard sensors, that is, wheel encoders, electrical current sensors and yaw rate gyroscope. Using these components, the system can characterise terrain online during normal vehicle operations. Experimental results obtained from different surfaces are presented to validate the system in the field showing its effectiveness and potential benefits to implement adaptive driving assistance systems or to automatically update the parameters of onboard control and planning algorithms.

  8. Terrain Extraction by Integrating Terrestrial Laser Scanner Data and Spectral Information

    Science.gov (United States)

    Lau, C. L.; Halim, S.; Zulkepli, M.; Azwan, A. M.; Tang, W. L.; Chong, A. K.

    2015-10-01

    The extraction of true terrain points from unstructured laser point cloud data is an important process in order to produce an accurate digital terrain model (DTM). However, most of these spatial filtering methods just utilizing the geometrical data to discriminate the terrain points from nonterrain points. The point cloud filtering method also can be improved by using the spectral information available with some scanners. Therefore, the objective of this study is to investigate the effectiveness of using the three-channel (red, green and blue) of the colour image captured from built-in digital camera which is available in some Terrestrial Laser Scanner (TLS) for terrain extraction. In this study, the data acquisition was conducted at a mini replica landscape in Universiti Teknologi Malaysia (UTM), Skudai campus using Leica ScanStation C10. The spectral information of the coloured point clouds from selected sample classes are extracted for spectral analysis. The coloured point clouds which within the corresponding preset spectral threshold are identified as that specific feature point from the dataset. This process of terrain extraction is done through using developed Matlab coding. Result demonstrates that a higher spectral resolution passive image is required in order to improve the output. This is because low quality of the colour images captured by the sensor contributes to the low separability in spectral reflectance. In conclusion, this study shows that, spectral information is capable to be used as a parameter for terrain extraction.

  9. Analysis of loads on wind turbines in complex terrain wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, K.; Markkilde Petersen, S. (The Test Station for Wind Turbines, Risoe National laboratory, Roskilde (Denmark)); Lading, P.; Sangill, O. (Windgineering ApS, Centre for Advanced Technology, Roskilde (Denmark))

    1992-09-01

    This paper describes structural load analysis of wind turbines erected in wind farms in complex terrain. The analysis is based on measurements on two Danwin turbines in Alta Mesa, San Gorgonia Pass California. The wind climate in wind farms in mountainous terrain differs significantly from wind conditions in homogeneous terrain, and this influences the turbine loading. Special attention is paid to characterize this difference by the wind turbulence characteristics. The power spectrum of the longitudinal turbulence component is investigated, and the measured wind conditions are analyzed in relation to what is expected for the free flow in homogenous terrain. The structural response is characterized by the main loads, i.e. blade and rotor loads. The response is related to the actual wind inflow. The relative importance of the deterministic and stochastic load-generating mechanisms is investigated. The azimuthal variations of the loads are calculated, and the load signals are spectral analyzed. The fatigue loads are estimated by Rainflow counting at different operational conditions and the resulting lifetime accumulated load spectra are calculated on the basis of wind distribution and turbulence level. The differences between lifetime fatigue loads seen in wind farms in complex terrain and wind farms in homogenous terrain are discussed. The accumulated load spectra are compared to the Danish Standard for Loads and Safety of Wind Turbines, and extensions to this standard are suggested for wind turbines erected in wind farm clusters. (au) (17 refs.).

  10. Millimeter-wave Interferometric Synthetic Aperture Radar Data Imaging Based on Terrain Surface Projection

    Directory of Open Access Journals (Sweden)

    Wei Shun-jun

    2015-02-01

    Full Text Available Millimeter-wave Interferometric Synthetic Aperture Radar (InSAR has smaller size, lower weight, and higher resolution compared with other bands. Thus, it has become a hot research topic. However, owing to its shorter wavelength, millimeter-wave InSAR data processing requires high-precision measurements of platform motion. For nonideal trajectories, traditional methods face difficulties in echo imaging and interferogram extraction. In addition, existing methods mainly produce SAR images based on plane projection. When the terrain changes abruptly, these methods may cause strong interferometric phase unwrapping and geometric distortion in SAR images. To overcome the abovementioned disadvantages of conventional methods in millimeter-wave InSAR imaging, an approach based on terrain surface projection is proposed. The echoes of different antennas are projected on the same terrain surface space for data imaging and interferogram extraction. In addition, the relation between terrain elevation and interferometric phase is derived. Simulations and experimental results verify the effectiveness of the proposed method; furthermore, the proposed approach improves the precision of interferometric phase extraction in complex motion conditions, while minimizing geometric distortion and phase wrapping in rough terrain, which is more conducive to terrain description and elevation inversion.

  11. An ice-rich flow origin for the banded terrain in the Hellas basin, Mars

    Science.gov (United States)

    Diot, X.; El-Maarry, M. R.; Guallini, L.; Schlunegger, F.; Norton, K. P.; Thomas, N.; Sutton, S.; Grindrod, P. M.

    2015-12-01

    The interior of Hellas Basin displays a complex landscape and a variety of geomorphological domains. One of these domains, the enigmatic banded terrain covers much of the northwestern part of the basin. We use high-resolution (Context Camera and High-Resolution Imaging Science Experiment) Digital Terrain Models to show that most of the complex viscous flowing behavior exhibited by the banded terrain is controlled by topography and flow-like interactions between neighboring banded terrain. Furthermore, the interior of the basin hosts several landforms suggestive of the presence of near-surface ice, which include polygonal patterns with elongated pits, scalloped depressions, isolated mounds, and collapse structures. We suggest that thermal contraction cracking and sublimation of near-surface ice are responsible for the formation and the development of most of the ice-related landforms documented in Hellas. The relatively pristine form, lack of superposed craters, and strong association with the banded terrain, suggest an Amazonian (water) expected in Hellas and summertime temperatures often exceeding the melting point of water ice suggest that the basin may have recorded relatively "temperate" climatic conditions compared to other places on Mars. Therefore, the potentially ice-rich banded terrain may have deformed with lower viscosity and stresses compared to other locations on Mars, which may account for its unique morphology.

  12. Impacts of terrain attributes and human activities on soil texture class variations in hilly areas, south-west China.

    Science.gov (United States)

    Li, Ai-Di; Guo, Peng-Tao; Wu, Wei; Liu, Hong-Bin

    2017-06-01

    Knowledge of soil texture variations is critical for agricultural and engineering applications because texture influences many other soil properties. This study used random forest method to evaluate the effects of human activities and topographic parameters on the spatial variability of soil texture in hilly areas where soil parent material was uniform. The study site covers 252 km 2 and is located in the Upper Yangtze River Basin of south-west China. A total of 3636 samples were collected from the cultivated soils at a depth of 20 cm of dryland (sloping field and terraced land) landscape. The soil texture class for each sample was estimated by experienced soil scientists in the field. Two soil texture classes (loam and clay) were observed in the watershed. Eleven terrain parameters were derived from a digital elevation model with a resolution of 30 m. Compared with loamy soils, clayey soils were mostly observed in the areas with lower elevation and gentle slopes. The outcome of random forest indicated that human activities and elevation had strong effects on soil texture class variations across the study site. Further results showed that the relative importance of terrain parameters to soil texture class variations varied with dryland landscape. Topographic wetness index and elevation were the most important variables for sloping field and terraced land landscapes, respectively.

  13. Close-Range Sensing Techniques in Alpine Terrain

    Science.gov (United States)

    Rutzinger, M.; Höfle, B.; Lindenbergh, R.; Oude Elberink, S.; Pirotti, F.; Sailer, R.; Scaioni, M.; Stötter, J.; Wujanz, D.

    2016-06-01

    Early career researchers such as PhD students are a main driving force of scientific research and are for a large part responsible for research innovation. They work on specialized topics within focused research groups that have a limited number of members, but might also have limited capacity in terms of lab equipment. This poses a serious challenge for educating such students as it is difficult to group a sufficient number of them to enable efficient knowledge transfer. To overcome this problem, the Innsbruck Summer School of Alpine Research 2015 on close-range sensing techniques in Alpine terrain was organized in Obergurgl, Austria, by an international team from several universities and research centres. Of the applicants a group of 40 early career researchers were selected with interest in about ten types of specialized surveying tools, i.e. laser scanners, a remotely piloted aircraft system, a thermal camera, a backpack mobile mapping system and different grade photogrammetric equipment. During the one-week summer school, students were grouped according to their personal preference to work with one such type of equipment under guidance of an expert lecturer. All students were required to capture and process field data on a mountain-related theme like landslides or rock glaciers. The work on the assignments lasted the whole week but was interspersed with lectures on selected topics by invited experts. The final task of the summer school participants was to present and defend their results to their peers, lecturers and other colleagues in a symposium-like setting. Here we present the framework and content of this summer school which brought together scientists from close-range sensing and environmental and geosciences.

  14. Mechanisms initiating deep convection over complex terrain during COPS

    Directory of Open Access Journals (Sweden)

    Christoph Kottmeier

    2008-12-01

    Full Text Available Precipitating convection in a mountain region of moderate topography is investigated, with particular emphasis on its initiation in response to boundary-layer and mid- and upper-tropospheric forcing mechanisms. The data used in the study are from COPS (Convective and Orographically-induced Precipitation Study that took place in southwestern Germany and eastern France in the summer of 2007. It is found that the initiation of precipitating convection can be roughly classified as being due to either: (i surface heating and low-level flow convergence; (ii surface heating and moisture supply overcoming convective inhibition during latent and/or potential instability; or (iii mid-tropospheric dynamical processes due to mesoscale convergence lines and forced mean vertical motion. These phenomena have to be adequately represented in models in order to improve quantitative precipitation forecast. Selected COPS cases are analysed and classified into these initiation categories. Although only a subset of COPS data (mainly radiosondes, surface weather stations, radar and satellite data are used here, it is shown that convective systems are captured in considerable detail by sensor synergy. Convergence lines were observed by Doppler radar in the location where deep convection is triggered several hours later. The results suggest that in many situations, observations of the location and timing of convergence lines will facilitate the nowcasting of convection. Further on, forecasting of the initiation of convection is significantly complicated if advection of potentially convective air masses over changing terrain features plays a major role. The passage of a frontal structure over the Vosges - Rhine valley - Black Forest orography was accompanied by an intermediate suppression of convection over the wide Rhine valley. Further downstream, an intensification of convection was observed over the Black Forest due to differential surface heating, a convergence line

  15. Wind Resource Assessment in Complex Terrain with a High-Resolution Numerical Weather Prediction Model

    Science.gov (United States)

    Gruber, Karin; Serafin, Stefano; Grubišić, Vanda; Dorninger, Manfred; Zauner, Rudolf; Fink, Martin

    2014-05-01

    A crucial step in planning new wind farms is the estimation of the amount of wind energy that can be harvested in possible target sites. Wind resource assessment traditionally entails deployment of masts equipped for wind speed measurements at several heights for a reasonably long period of time. Simplified linear models of atmospheric flow are then used for a spatial extrapolation of point measurements to a wide area. While linear models have been successfully applied in the wind resource assessment in plains and offshore, their reliability in complex terrain is generally poor. This represents a major limitation to wind resource assessment in Austria, where high-altitude locations are being considered for new plant sites, given the higher frequency of sustained winds at such sites. The limitations of linear models stem from two key assumptions in their formulation, the neutral stratification and attached boundary-layer flow, both of which often break down in complex terrain. Consequently, an accurate modeling of near-surface flow over mountains requires the adoption of a NWP model with high horizontal and vertical resolution. This study explores the wind potential of a site in Styria in the North-Eastern Alps. The WRF model is used for simulations with a maximum horizontal resolution of 800 m. Three nested computational domains are defined, with the innermost one encompassing a stretch of the relatively broad Enns Valley, flanked by the main crest of the Alps in the south and the Nördliche Kalkalpen of similar height in the north. In addition to the simulation results, we use data from fourteen 10-m wind measurement sites (of which 7 are located within valleys and 5 near mountain tops) and from 2 masts with anemometers at several heights (at hillside locations) in an area of 1600 km2 around the target site. The potential for wind energy production is assessed using the mean wind speed and turbulence intensity at hub height. The capacity factor is also evaluated

  16. Influence of terrain and highway construction on thermokarst distribution, North Slave region, NWT, Canada

    Science.gov (United States)

    Morse, Peter; Wolfe, Stephen; McWade, Taylor

    2017-04-01

    Permafrost degradation has been observed throughout the north and is expected to have broad reaching effects on the land and its people. Nevertheless, for much of Northern Canada little quantified information about thermokarst exists. For example, in the southern North Slave region, NWT, thermokarst distribution has never been assessed though permafrost is in thermal disequilibrium and modelling suggests permafrost extent will decline. Additionally, differential subsidence has been observed in the subarctic city of Yellowknife and along highway infrastructure connecting it to the south. To better understand present and future permafrost conditions, we mapped the location and size of thermokarst ponding (a change from forest cover to water) in the study area by comparing historic and modern remotely sensed data sets available from 1945, 1961, and 2005. These data were used to evaluate the dominant terrain controls on the distribution of thermokarst in the region, and the potential influence that highway construction may have had on thermokarst development. Historically, discontinuous permafrost developed in a time-transgressive manner during the Holocene as lake-level receded from glacial Lake McConnell to present-day Great Slave Lake (5 mmṡa-1 over the last 8000 years). As a consequence of inundation the upland areas are characterized by extensive wave-washed bedrock outcrops with glaciolacustrine (GL) sediments and glaciofluvial materials occurring between them, whereas the lowland areas feature prominent GL deposits that cover nearly 70 % of the exposed surface. Throughout much of the region ground ice accumulation likely accompanied permafrost aggradation into fine-grained sediments, as is evident by lithalsa growth in particular. Highway 3, constructed during the mid-1960s, was preferentially aligned to crossed terrain underlain by fine-grained sediments to avoid bedrock and waterbodies. Local silt and clay used for highway embankment construction was sourced

  17. Error Analysis of Satellite Precipitation-Driven Modeling of Flood Events in Complex Alpine Terrain

    Directory of Open Access Journals (Sweden)

    Yiwen Mei

    2016-03-01

    Full Text Available The error in satellite precipitation-driven complex terrain flood simulations is characterized in this study for eight different global satellite products and 128 flood events over the Eastern Italian Alps. The flood events are grouped according to two flood types: rain floods and flash floods. The satellite precipitation products and runoff simulations are evaluated based on systematic and random error metrics applied on the matched event pairs and basin-scale event properties (i.e., rainfall and runoff cumulative depth and time series shape. Overall, error characteristics exhibit dependency on the flood type. Generally, timing of the event precipitation mass center and dispersion of the time series derived from satellite precipitation exhibits good agreement with the reference; the cumulative depth is mostly underestimated. The study shows a dampening effect in both systematic and random error components of the satellite-driven hydrograph relative to the satellite-retrieved hyetograph. The systematic error in shape of the time series shows a significant dampening effect. The random error dampening effect is less pronounced for the flash flood events and the rain flood events with a high runoff coefficient. This event-based analysis of the satellite precipitation error propagation in flood modeling sheds light on the application of satellite precipitation in mountain flood hydrology.

  18. Assessing the Value of UAV Photogrammetry for Characterizing Terrain in Complex Peatlands

    Directory of Open Access Journals (Sweden)

    Julie Lovitt

    2017-07-01

    Full Text Available Microtopographic variability in peatlands has a strong influence on greenhouse gas fluxes, but we lack the ability to characterize terrain in these environments efficiently over large areas. To address this, we assessed the capacity of photogrammetric data acquired from an unmanned aerial vehicle (UAV or drone to reproduce ground elevations measured in the field. In particular, we set out to evaluate the role of (i vegetation/surface complexity and (ii supplementary LiDAR data on results. We compared remote-sensing observations to reference measurements acquired with survey grade GPS equipment at 678 sample points, distributed across a 61-hectare treed bog in northwestern Alberta, Canada. UAV photogrammetric data were found to capture elevation with accuracies, by root mean squares error, ranging from 14–42 cm, depending on the state of vegetation/surface complexity. We judge the technology to perform well under all but the most-complex conditions, where ground visibility is hindered by thick vegetation. Supplementary LiDAR data did not improve results significantly, nor did it perform well as a stand-alone technology at the low densities typically available to researchers.

  19. Forecasting Organized Crime Homicides: Risk Terrain Modeling of Camorra Violence in Naples, Italy.

    Science.gov (United States)

    Dugato, Marco; Calderoni, Francesco; Berlusconi, Giulia

    2017-06-01

    Mafia homicides are usually committed for retaliation, economic profit, or rivalry among groups. The variety of possible reasons suggests the inefficacy of a preventive approach. However, like most violent crimes, mafia homicides concentrate in space due to place-specific social and environmental features. Starting from the existing literature, this study applies the Risk Terrain Modeling approach to forecast the Camorra homicides in Naples, Italy. This approach is based on the identification and evaluation of the underlying risk factors able to affect the risk of a homicide. This information is then used to predict the most likely location of future events. The findings of this study demonstrate that past homicides, drug dealing, confiscated assets, and rivalries among groups make it possible to predict up to 85% of 2012 mafia homicides, identifying 11% of city areas at highest risk. By contrast, variables controlling for the socio-economic conditions of areas are not significantly related to the risk of homicide. Moreover, this study shows that, even in a restricted space, the same risk factors may combine in different ways, giving rise to areas of equal risk but requiring targeted remedies. These results provide an effective basis for short- and long-term targeted policing strategies against organized crime- and gang-related violence. A similar approach may also provide practitioners, policy makers, and local administrators in other countries with significant support in understanding and counteracting also other forms of violent behavior by gangs or organized crime groups.

  20. Water quality in relation to vegetative buffers around sinkholes in karst terrain

    Science.gov (United States)

    Petersen, A.; Vondracek, B.

    2006-01-01

    There are approximately 8,340 mapped sinkholes in karst terrain of southeast Minnesota. Most sinkholes are adjacent to row crops that likely contribute pollutants to surface waters and aquifers. Vegetated buffers can improve water quality by reducing sediment, fertilizers, pesticides, and other potential contaminants from runoff, and may benefit water quality when placed around sinkholes. We evaluated sediment, nitrogen, phosphorus, and runoff for buffers from 2.5 to 30 m (8.3 to 98 ft) wide with a spreadsheet model. We found buffers 30 m (98 ft) wide may reduce pollution by 80 percent, although buffers 15 m (49 ft) wide may be most cost effective. Buffers could contribute to goals of reducing sediment, nitrogen, and phosphorus loads in Minnesota waters. Buffers 15 m (49 ft) wide around all sinkholes would retire approximately 436 ha (1,077 ac) of land from production and cost approximately $260,000 yr-1 based on Conservation Reserve Program payments, while requiring <14 percent of the budget of the program for groundwater protection in southeast Minnesota.

  1. The influences on radar-based rainfall estimation due to complex terrain

    Science.gov (United States)

    Craciun, Cristian; Stefan, Sabina

    2017-04-01

    One of the concerns regarding radar-based quantitative precipitation estimation (QPE) is the level of reliability of radar data, on which the forecaster should trust when he must issue warnings regarding weather phenomena that might put human lives and good in danger. The aim of the current study is to evaluate, by objective means, the difference between radar estimated and gauge measured precipitation over an area with complex terrain. Radar data supplied for the study comes from an S-band, single polarization, Doppler weather system, Weather Surveillance Radar 98 Doppler (WSR-98D), that is located in center part of Romania. Gage measurements are supplied by a net of 27 weather stations, located within the coverage area of the radar. The approach consists in a few steps. In the first one the field of reflectivity data is converted into rain rate, using the radar's native Z-R relationship, and the rain rate field is then transformed into rain accumulation over certain time intervals. In the next step were investigated the differences between radar and gauge rainfall accumulations by using four objective functions: mean bias between radar estimations and ground measurements, root mean square factor, and Spearman and Pearson correlations. The results shows that the differences and the correlations between radar-based accumulations and rain gauge amounts have rather local significance than general relevance over the studied area.

  2. Dispersion of TSP and PM(10) emissions from quarries in complex terrain.

    Science.gov (United States)

    Tartakovsky, Dmitry; Stern, Eli; Broday, David M

    2016-01-15

    This study evaluates AERMOD and CALPUFF dispersion calculations of particulate matter emissions from stone quarries in two mountainous regions against TSP and PM10 measurements, using both observational and WRF-modeled meteorological data. Due to different model parameterization, AERMOD dispersion predictions were in better agreement with the measured concentrations than those obtained by CALPUFF. As expected, the smaller the distance between the meteorological station, the source (quarry) and the receptors, the better the predictions of both AERMOD and CALPUFF. In contrast, using in-situ wind field obtained by runs of the WRF meteorological model for the complex terrain study area provided, in general, less accurate dispersion estimates than when using (even remote) meteorological observations. In particular, using the three-dimensional WRF-modeled wind field within CALPUFF did not provide any advantage over using the two-dimensional wind field, which is the common procedure of AERMOD and CALPUFF. Dry deposition was more significant for ambient concentration estimation in AERMOD than in CALPUFF. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. MELSAR: a mesoscale air quality model for complex terrain. Volume 2. Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Allwine, K.J.; Whiteman, C.D.

    1985-04-01

    This final report is submitted as part of the Green River Ambient Model Assessment (GRAMA) project conducted at the US Department of Energy's Pacific Northwest Laboratory for the US Environmental Protection Agency. The GRAMA Program has, as its ultimate goal, the development of validated air quality models that can be applied to the complex terrain of the Green River Formation of western Colorado, eastern Utah and southern Wyoming. The Green River Formation is a geologic formation containing large reserves of oil shale, coal, and other natural resources. Development of these resources may lead to a degradation of the air quality of the region. Air quality models are needed immediately for planning and regulatory purposes to assess the magnitude of these regional impacts. This report documents one of the models being developed for this purpose within GRAMA - specifically a model to predict short averaging time (less than or equal to 24 h) pollutant concentrations resulting from the mesoscale transport of pollutant releases from multiple sources. MELSAR has not undergone any rigorous operational testing, sensitivity analyses, or validation studies. Testing and evaluation of the model are needed to gain a measure of confidence in the model's performance. This report consists of two volumes. This volume contains the Appendices, which include listings of the FORTRAN code and Volume 1 contains the model overview, technical description, and user's guide. 13 figs., 10 tabs.

  4. Comparison of Measured and Numerically Simulated Turbulence Statistics in a Convective Boundary Layer Over Complex Terrain

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Raj K.; Berg, Larry K.; Kosović, Branko; Mirocha, Jeffrey D.; Pekour, Mikhail S.; Shaw, William J.

    2016-11-25

    High resolution numerical simulation can provide insight into important physical processes that occur within the planetary boundary layer (PBL). The present work employs large eddy simulation (LES) using the Weather Forecasting and Research (WRF) model, with the LES domain nested within mesoscale simulation, to simulate real conditions in the convective PBL over an area of complex terrain. A multiple nesting approach has been used to downsize the grid spacing from 12.15 km (mesoscale) to 0.03 km (LES). A careful selection of grid spacing in the WRF Meso domain has been conducted to minimize artifacts in the WRF-LES solutions. The WRF-LES results have been evaluated with in situ and remote sensing observations collected during the US Department of Energy-supported Columbia BasinWind Energy Study (CBWES). Comparison of the first- and second-order moments, turbulence spectrum, and probability density function (PDF) of wind speed shows good agreement between the simulations and data. Furthermore, the WRF-LES variables show a great deal of variability in space and time caused by the complex topography in the LES domain. The WRF-LES results show that the flow structures, such as roll vortices and convective cells, vary depending on both the location and time of day. In addition to basic studies related to boundary-layer meteorology, results from these simulations can be used in other applications, such as studying wind energy resources, atmospheric dispersion, fire weather etc.

  5. Cooperative Behaviours with Swarm Intelligence in Multirobot Systems for Safety Inspections in Underground Terrains

    Directory of Open Access Journals (Sweden)

    Chika Yinka-Banjo

    2014-01-01

    Full Text Available Underground mining operations are carried out in hazardous environments. To prevent disasters from occurring, as often as they do in underground mines, and to prevent safety routine checkers from disasters during safety inspection checks, multirobots are suggested to do the job of safety inspection rather than human beings and single robots. Multirobots are preferred because the inspection task will be done in the minimum amount of time. This paper proposes a cooperative behaviour for a multirobot system (MRS to achieve a preentry safety inspection in underground terrains. A hybrid QLACS swarm intelligent model based on Q-Learning (QL and the Ant Colony System (ACS was proposed to achieve this cooperative behaviour in MRS. The intelligent model was developed by harnessing the strengths of both QL and ACS algorithms. The ACS optimizes the routes used for each robot while the QL algorithm enhances the cooperation between the autonomous robots. A description of a communicating variation within the QLACS model for cooperative behavioural purposes is presented. The performance of the algorithms in terms of without communication, with communication, computation time, path costs, and the number of robots used was evaluated by using a simulation approach. Simulation results show achieved cooperative behaviour between robots.

  6. Assessment of GF-3 Polarimetric SAR Data for Physical Scattering Mechanism Analysis and Terrain Classification.

    Science.gov (United States)

    Yin, Junjun; Yang, Jian; Zhang, Qingjun

    2017-12-01

    On 10 August 2016 China launched the GF-3, its first C-band polarimetric synthetic aperture radar (SAR) satellite, which was put into operation at the end of January, 2017. GF-3 polarimetric SAR has many advantages such as high resolution and multi-polarization imaging capabilities. Polarimetric SAR can fully characterize the backscatter property of targets, and thus it is of great interest to explore the physical scattering mechanisms of terrain types, which is very important in interpreting polarimetric SAR imagery and for its further usages in Earth observations. In this paper, focusing on target scattering characterization and feature extraction, we generalize the Δ α B / α B method, which was proposed under the reflection symmetric assumption, for the general backscatter process to account for both the reflection symmetry and asymmetry cases. Then, we evaluate the performances of physical scattering mechanism analysis methods for GF-3 polarimetric SAR imagery. Radarsat-2 data acquired over the same area is used for cross validation. Results show that GF-3 polarimetric SAR data has great potential for target characterization, especially for ocean area observation.

  7. Comparison of Measured and Numerically Simulated Turbulence Statistics in a Convective Boundary Layer Over Complex Terrain

    Science.gov (United States)

    Rai, Raj K.; Berg, Larry K.; Kosović, Branko; Mirocha, Jeffrey D.; Pekour, Mikhail S.; Shaw, William J.

    2017-04-01

    The Weather Research and Forecasting (WRF) model can be used to simulate atmospheric processes ranging from quasi-global to tens of m in scale. Here we employ large-eddy simulation (LES) using the WRF model, with the LES-domain nested within a mesoscale WRF model domain with grid spacing decreasing from 12.15 km (mesoscale) to 0.03 km (LES). We simulate real-world conditions in the convective planetary boundary layer over an area of complex terrain. The WRF-LES model results are evaluated against observations collected during the US Department of Energy-supported Columbia Basin Wind Energy Study. Comparison of the first- and second-order moments, turbulence spectrum, and probability density function of wind speed shows good agreement between the simulations and observations. One key result is to demonstrate that a systematic methodology needs to be applied to select the grid spacing and refinement ratio used between domains, to avoid having a grid resolution that falls in the grey zone and to minimize artefacts in the WRF-LES model solutions. Furthermore, the WRF-LES model variables show large variability in space and time caused by the complex topography in the LES domain. Analyses of WRF-LES model results show that the flow structures, such as roll vortices and convective cells, vary depending on both the location and time of day as well as the distance from the inflow boundaries.

  8. Solar resources estimation combining digital terrain models and satellite images techniques

    Energy Technology Data Exchange (ETDEWEB)

    Bosch, J.L.; Batlles, F.J. [Universidad de Almeria, Departamento de Fisica Aplicada, Ctra. Sacramento s/n, 04120-Almeria (Spain); Zarzalejo, L.F. [CIEMAT, Departamento de Energia, Madrid (Spain); Lopez, G. [EPS-Universidad de Huelva, Departamento de Ingenieria Electrica y Termica, Huelva (Spain)

    2010-12-15

    One of the most important steps to make use of any renewable energy is to perform an accurate estimation of the resource that has to be exploited. In the designing process of both active and passive solar energy systems, radiation data is required for the site, with proper spatial resolution. Generally, a radiometric stations network is used in this evaluation, but when they are too dispersed or not available for the study area, satellite images can be utilized as indirect solar radiation measurements. Although satellite images cover wide areas with a good acquisition frequency they usually have a poor spatial resolution limited by the size of the image pixel, and irradiation must be interpolated to evaluate solar irradiation at a sub-pixel scale. When pixels are located in flat and homogeneous areas, correlation of solar irradiation is relatively high, and classic interpolation can provide a good estimation. However, in complex topography zones, data interpolation is not adequate and the use of Digital Terrain Model (DTM) information can be helpful. In this work, daily solar irradiation is estimated for a wide mountainous area using a combination of Meteosat satellite images and a DTM, with the advantage of avoiding the necessity of ground measurements. This methodology utilizes a modified Heliosat-2 model, and applies for all sky conditions; it also introduces a horizon calculation of the DTM points and accounts for the effect of snow covers. Model performance has been evaluated against data measured in 12 radiometric stations, with results in terms of the Root Mean Square Error (RMSE) of 10%, and a Mean Bias Error (MBE) of +2%, both expressed as a percentage of the mean value measured. (author)

  9. Spatial distribution of thermokarst terrain in Arctic Alaska

    Science.gov (United States)

    Farquharson, L. M.; Mann, D. H.; Grosse, G.; Jones, B. M.; Romanovsky, V. E.

    2016-11-01

    In landscapes underlain by ice-rich permafrost, the development of thermokarst landforms can have drastic impacts on ecosystem processes and human infrastructure. Here we describe the distribution of thermokarst landforms in the continuous permafrost zone of Arctic Alaska, analyze linkages to the underlying surficial geology, and discuss the vulnerability of different types of landscapes to future thaw. We identified nine major thermokarst landforms and then mapped their distributions in twelve representative study areas totaling 300-km2. These study areas differ in their geologic history, permafrost-ice content, and ground thermal regime. Results show that 63% of the entire study area is occupied by thermokarst landforms and that the distribution of thermokarst landforms and overall landscape complexity varies markedly with surficial geology. Areas underlain by ice-rich marine silt are the most affected by thermokarst (97% of total area), whereas areas underlain by glacial drift are least affected (14%). Drained thermokarst-lake basins are the most widespread thermokarst landforms, covering 33% of the entire study region, with greater prevalence in areas of marine silt (48% coverage), marine sand (47%), and aeolian silt (34%). Thermokarst-lakes are the second most common thermokarst landform, covering 16% of the study region, with highest coverage in areas underlain by marine silt (39% coverage). Thermokarst troughs and pits cover 7% of the study region and are the third most prevalent thermokarst landform. They are most common in areas underlain by deltaic sands and gravels (18% coverage) and marine sand (12%). Alas valleys are widespread in areas of aeolian silt (14%) located in gradually sloping uplands. Areas of marine silt have been particularly vulnerable to thaw in the past because they are ice-rich and have low-gradient topography facilitating the repeated development of thermokarst-lakes. In the future, ice-rich aeolian, upland terrain (yedoma) will be

  10. AERIAL TERRAIN MAPPING USING UNMANNED AERIAL VEHICLE APPROACH

    Directory of Open Access Journals (Sweden)

    K. N. Tahar

    2012-08-01

    Full Text Available This paper looks into the latest achievement in the low-cost Unmanned Aerial Vehicle (UAV technology in their capacity to map the semi-development areas. The objectives of this study are to establish a new methodology or a new algorithm in image registration during interior orientation process and to determine the accuracy of the photogrammetric products by using UAV images. Recently, UAV technology has been used in several applications such as mapping, agriculture and surveillance. The aim of this study is to scrutinize the usage of UAV to map the semi-development areas. The performance of the low cost UAV mapping study was established on a study area with two image processing methods so that the results could be comparable. A non-metric camera was attached at the bottom of UAV and it was used to capture images at both sites after it went through several calibration steps. Calibration processes were carried out to determine focal length, principal distance, radial lens distortion, tangential lens distortion and affinity. A new method in image registration for a non-metric camera is discussed in this paper as a part of new methodology of this study. This method used the UAV Global Positioning System (GPS onboard to register the UAV image for interior orientation process. Check points were established randomly at both sites using rapid static Global Positioning System. Ground control points are used for exterior orientation process, and check point is used for accuracy assessment of photogrammetric product. All acquired images were processed in a photogrammetric software. Two methods of image registration were applied in this study, namely, GPS onboard registration and ground control point registration. Both registrations were processed by using photogrammetric software and the result is discussed. Two results were produced in this study, which are the digital orthophoto and the digital terrain model. These results were analyzed by using the root

  11. Aerial Terrain Mapping Using Unmanned Aerial Vehicle Approach

    Science.gov (United States)

    Tahar, K. N.

    2012-08-01

    This paper looks into the latest achievement in the low-cost Unmanned Aerial Vehicle (UAV) technology in their capacity to map the semi-development areas. The objectives of this study are to establish a new methodology or a new algorithm in image registration during interior orientation process and to determine the accuracy of the photogrammetric products by using UAV images. Recently, UAV technology has been used in several applications such as mapping, agriculture and surveillance. The aim of this study is to scrutinize the usage of UAV to map the semi-development areas. The performance of the low cost UAV mapping study was established on a study area with two image processing methods so that the results could be comparable. A non-metric camera was attached at the bottom of UAV and it was used to capture images at both sites after it went through several calibration steps. Calibration processes were carried out to determine focal length, principal distance, radial lens distortion, tangential lens distortion and affinity. A new method in image registration for a non-metric camera is discussed in this paper as a part of new methodology of this study. This method used the UAV Global Positioning System (GPS) onboard to register the UAV image for interior orientation process. Check points were established randomly at both sites using rapid static Global Positioning System. Ground control points are used for exterior orientation process, and check point is used for accuracy assessment of photogrammetric product. All acquired images were processed in a photogrammetric software. Two methods of image registration were applied in this study, namely, GPS onboard registration and ground control point registration. Both registrations were processed by using photogrammetric software and the result is discussed. Two results were produced in this study, which are the digital orthophoto and the digital terrain model. These results were analyzed by using the root mean square

  12. Climbing Mt. Sharp: Maximizing Curiosity's Science Over Traversable Terrains

    Science.gov (United States)

    Fraeman, A. A.; Arvidson, R. E.; Bellutta, P.; Sletten, R. S.; Team, M.

    2013-12-01

    As Curiosity transitions from the plains of Gale Crater to the flanks of Mt. Sharp, the rover will begin to encounter material and terrains that could present greater mobility challenges. These challenges include the presence of significantly steeper slopes and large dunes that have the potential to embed the vehicle. Strategic path planning during this phase of the mission will therefore require carefully selecting a traversable route that is both time-efficient and that will provide access to the most scientifically rewarding targets. We consider possible solutions to this optimization problem by examining multiple orbital data sets in order to locate likely mobility hazards and to select potential science waypoints for future in situ investigation. High resolution HiRISE monochromatic images and digital elevation models show filled craters, rock fields, areas with slopes too steep for the rover to traverse, and other possible mobility obstacles on the northwest flank of Mt. Sharp. Using this context, we review accessibility to scientific targets on Mt. Sharp that have been previously discussed in landing site workshop presentations and peer-reviewed publications. Additionally, we identify new targets using detailed geologic maps combined with oversampled CRISM observations that provide mineralogical information at unprecedented high spatial resolutions (up to 6 m/pixel). For example, the spatially sharpened CRISM spectral data show a localized hematite deposit that is associated with the upper-most stratum of a ridge which is located ~3km from the rover's entry point to Mt. Sharp. This deposit may represent a previously habitable environment and is therefore a high priority target for in situ investigation. In order to study the hematite and also to eventually access the phyllosilicate-bearing trough that is located directly behind the ridge, Curiosity will have to cross this ridge, but the ridge edges are often defined by regions with slopes that are too steep

  13. Stochastic Cascade Dynamical Downscaling of Precipitation over Complex Terrain

    Science.gov (United States)

    Posadas, A.; Duffaut, L. E.; Jones, C.; Carvalho, L. V.; Carbajal, M.; Heidinger, H.; Quiroz, R.

    2013-12-01

    spatial and temporal variability of rainfall between the rainfall fields obtained from the rain gauge network and those generated by the simulation model. The potential advantages of this methodology are discussed.Stochastic Cascade Dynamical Downscaling of Precipitation over Complex Terrain

  14. Spatial distribution of thermokarst terrain in Arctic Alaska

    Science.gov (United States)

    Farquharson, Louise; Mann, Dan H; Grosse, Guido; Jones, Benjamin M.; Romanovsky, Vladimir

    2016-01-01

    In landscapes underlain by ice-rich permafrost, the development of thermokarst landforms can have drastic impacts on ecosystem processes and human infrastructure. Here we describe the distribution of thermokarst landforms in the continuous permafrost zone of Arctic Alaska, analyze linkages to the underlying surficial geology, and discuss the vulnerability of different types of landscapes to future thaw. We identified nine major thermokarst landforms and then mapped their distributions in twelve representative study areas totaling 300-km2. These study areas differ in their geologic history, permafrost-ice content, and ground thermal regime. Results show that 63% of the entire study area is occupied by thermokarst landforms and that the distribution of thermokarst landforms and overall landscape complexity varies markedly with surficial geology. Areas underlain by ice-rich marine silt are the most affected by thermokarst (97% of total area), whereas areas underlain by glacial drift are least affected (14%). Drained thermokarst-lake basins are the most widespread thermokarst landforms, covering 33% of the entire study region, with greater prevalence in areas of marine silt (48% coverage), marine sand (47%), and aeolian silt (34%). Thermokarst-lakes are the second most common thermokarst landform, covering 16% of the study region, with highest coverage in areas underlain by marine silt (39% coverage). Thermokarst troughs and pits cover 7% of the study region and are the third most prevalent thermokarst landform. They are most common in areas underlain by deltaic sands and gravels (18% coverage) and marine sand (12%). Alas valleys are widespread in areas of aeolian silt (14%) located in gradually sloping uplands. Areas of marine silt have been particularly vulnerable to thaw in the past because they are ice-rich and have low-gradient topography facilitating the repeated development of thermokarst-lakes. In the future, ice-rich aeolian, upland terrain (yedoma) will be

  15. Secondary chaotic terrain formation in the higher outflow channels of southern circum-Chryse, Mars

    Science.gov (United States)

    Rodriguez, J.A.P.; Kargel, J.S.; Tanaka, K.L.; Crown, D.A.; Berman, D.C.; Fairen, A.G.; Baker, V.R.; Furfaro, R.; Candelaria, P.; Sasaki, S.

    2011-01-01

    Higher outflow channel dissection in the martian region of southern circum-Chryse appears to have extended from the Late Hesperian to the Middle Amazonian Epoch. These outflow channels were excavated within the upper 1. km of the cryolithosphere, where no liquid water is expected to have existed during these geologic epochs. In accordance with previous work, our examination of outflow channel floor morphologies suggests the upper crust excavated by the studied outflow channels consisted of a thin (a few tens of meters) layer of dry geologic materials overlying an indurated zone that extends to the bases of the investigated outflow channels (1. km in depth). We find that the floors of these outflow channels contain widespread secondary chaotic terrains (i.e., chaotic terrains produced by the destruction of channel-floor materials). These chaotic terrains occur within the full range of outflow channel dissection and tend to form clusters. Our examination of the geology of these chaotic terrains suggests that their formation did not result in the generation of floods. Nevertheless, despite their much smaller dimensions, these chaotic terrains are comprised of the same basic morphologic elements (e.g., mesas, knobs, and smooth deposits within scarp-bound depressions) as those located in the initiation zones of the outflow channels, which suggests that their formation must have involved the release of ground volatiles. We propose that these chaotic terrains developed not catastrophically but gradually and during multiple episodes of nested surface collapse. In order to explain the formation of secondary chaotic terrains within zones of outflow channel dissection, we propose that the regional Martian cryolithosphere contained widespread lenses of volatiles in liquid form. In this model, channel floor collapse and secondary chaotic terrain formation would have taken place as a consequence of instabilities arising during their exhumation by outflow channel dissection

  16. Characterization of Course and Terrain and Their Effect on Skier Speed in World Cup Alpine Ski Racing

    Science.gov (United States)

    Gilgien, Matthias; Crivelli, Philip; Spörri, Jörg; Kröll, Josef; Müller, Erich

    2015-01-01

    World Cup (WC) alpine ski racing consists of four main competition disciplines (slalom, giant slalom, super-G and downhill), each with specific course and terrain characteristics. The International Ski Federation (FIS) has regulated course length, altitude drop from start to finish and course setting in order to specify the characteristics of the respective competition disciplines and to control performance and injury-related aspects. However to date, no detailed data on course setting and its adaptation to terrain is available. It is also unknown how course and terrain characteristics influence skier speed. Therefore, the aim of the study was to characterize course setting, terrain geomorphology and their relationship to speed in male WC giant slalom, super-G and downhill. The study revealed that terrain was flatter in downhill compared to the other disciplines. In all disciplines, variability in horizontal gate distance (gate offset) was larger than in gate distance (linear distance from gate to gate). In giant slalom the horizontal gate distance increased with terrain inclination, while super-G and downhill did not show such a connection. In giant slalom and super-G, there was a slight trend towards shorter gate distances as the steepness of the terrain increased. Gates were usually set close to terrain transitions in all three disciplines. Downhill had a larger proportion of extreme terrain inclination changes along the skier trajectory per unit time skiing than the other disciplines. Skier speed decreased with increasing steepness of terrain in all disciplines except for downhill. In steep terrain, speed was found to be controllable by increased horizontal gate distances in giant slalom and by shorter gate distances in giant slalom and super-G. Across the disciplines skier speed was largely explained by course setting and terrain inclination in a multiple linear model. PMID:25760039

  17. Characterization of course and terrain and their effect on skier speed in World Cup alpine ski racing.

    Directory of Open Access Journals (Sweden)

    Matthias Gilgien

    Full Text Available World Cup (WC alpine ski racing consists of four main competition disciplines (slalom, giant slalom, super-G and downhill, each with specific course and terrain characteristics. The International Ski Federation (FIS has regulated course length, altitude drop from start to finish and course setting in order to specify the characteristics of the respective competition disciplines and to control performance and injury-related aspects. However to date, no detailed data on course setting and its adaptation to terrain is available. It is also unknown how course and terrain characteristics influence skier speed. Therefore, the aim of the study was to characterize course setting, terrain geomorphology and their relationship to speed in male WC giant slalom, super-G and downhill. The study revealed that terrain was flatter in downhill compared to the other disciplines. In all disciplines, variability in horizontal gate distance (gate offset was larger than in gate distance (linear distance from gate to gate. In giant slalom the horizontal gate distance increased with terrain inclination, while super-G and downhill did not show such a connection. In giant slalom and super-G, there was a slight trend towards shorter gate distances as the steepness of the terrain increased. Gates were usually set close to terrain transitions in all three disciplines. Downhill had a larger proportion of extreme terrain inclination changes along the skier trajectory per unit time skiing than the other disciplines. Skier speed decreased with increasing steepness of terrain in all disciplines except for downhill. In steep terrain, speed was found to be controllable by increased horizontal gate distances in giant slalom and by shorter gate distances in giant slalom and super-G. Across the disciplines skier speed was largely explained by course setting and terrain inclination in a multiple linear model.

  18. Characterization of course and terrain and their effect on skier speed in World Cup alpine ski racing.

    Science.gov (United States)

    Gilgien, Matthias; Crivelli, Philip; Spörri, Jörg; Kröll, Josef; Müller, Erich

    2015-01-01

    World Cup (WC) alpine ski racing consists of four main competition disciplines (slalom, giant slalom, super-G and downhill), each with specific course and terrain characteristics. The International Ski Federation (FIS) has regulated course length, altitude drop from start to finish and course setting in order to specify the characteristics of the respective competition disciplines and to control performance and injury-related aspects. However to date, no detailed data on course setting and its adaptation to terrain is available. It is also unknown how course and terrain characteristics influence skier speed. Therefore, the aim of the study was to characterize course setting, terrain geomorphology and their relationship to speed in male WC giant slalom, super-G and downhill. The study revealed that terrain was flatter in downhill compared to the other disciplines. In all disciplines, variability in horizontal gate distance (gate offset) was larger than in gate distance (linear distance from gate to gate). In giant slalom the horizontal gate distance increased with terrain inclination, while super-G and downhill did not show such a connection. In giant slalom and super-G, there was a slight trend towards shorter gate distances as the steepness of the terrain increased. Gates were usually set close to terrain transitions in all three disciplines. Downhill had a larger proportion of extreme terrain inclination changes along the skier trajectory per unit time skiing than the other disciplines. Skier speed decreased with increasing steepness of terrain in all disciplines except for downhill. In steep terrain, speed was found to be controllable by increased horizontal gate distances in giant slalom and by shorter gate distances in giant slalom and super-G. Across the disciplines skier speed was largely explained by course setting and terrain inclination in a multiple linear model.

  19. CONTEXT-BASED URBAN TERRAIN RECONSTRUCTION FROM UAV-VIDEOS FOR GEOINFORMATION APPLICATIONS

    Directory of Open Access Journals (Sweden)

    D. Bulatov

    2012-09-01

    Full Text Available Urban terrain reconstruction has many applications in areas of civil engineering, urban planning, surveillance and defense research. Therefore the needs of covering ad-hoc demand and performing a close-range urban terrain reconstruction with miniaturized and relatively inexpensive sensor platforms are constantly growing. Using (miniaturized unmanned aerial vehicles, (MUAVs, represents one of the most attractive alternatives to conventional large-scale aerial imagery. We cover in this paper a four-step procedure of obtaining georeferenced 3D urban models from video sequences. The four steps of the procedure – orientation, dense reconstruction, urban terrain modeling and geo-referencing – are robust, straight-forward, and nearly fully-automatic. The two last steps – namely, urban terrain modeling from almost-nadir videos and co-registration of models 6ndash; represent the main contribution of this work and will therefore be covered with more detail. The essential substeps of the third step include digital terrain model (DTM extraction, segregation of buildings from vegetation, as well as instantiation of building and tree models. The last step is subdivided into quasi- intrasensorial registration of Euclidean reconstructions and intersensorial registration with a geo-referenced orthophoto. Finally, we present reconstruction results from a real data-set and outline ideas for future work.

  20. Wind farm layout optimization in complex terrain: A preliminary study on a Gaussian hill

    Science.gov (United States)

    Feng, J.; Shen, W. Z.

    2014-06-01

    One of the crucial problems for wind farm (WF) development is wind farm layout optimization. It seeks to find the optimal positions of wind turbines (WTs) inside a WF, so as to maximize and/or minimize a single objective or multiple objectives, while satisfying certain constraints. Although this problem for WFs in flat terrain or offshore has been investigated in many studies, it is still a challenging problem for WFs in complex terrain. In this preliminary study, the wind flow conditions of complex terrain without WTs are first obtained from computational fluid dynamics (CFD) simulation, then an adapted Jensen wake model is developed by considering the terrain features and taking the inflow conditions as input. Using this combined method, the wake effects of WF in complex terrain are properly modelled. Besides, a random search (RS) algorithm proposed in previous study is improved by adding some adaptive mechanisms and applied to solve the layout optimization problem of a WF on a Gaussian shape hill. The layout of the WF with a certain number of WTs is optimized to maximize the total power output, which obtained steady improvements over expert guess layouts.

  1. Birds achieve high robustness in uneven terrain through active control of landing conditions.

    Science.gov (United States)

    Birn-Jeffery, Aleksandra V; Daley, Monica A

    2012-06-15

    We understand little about how animals adjust locomotor behaviour to negotiate uneven terrain. The mechanical demands and constraints of such behaviours likely differ from uniform terrain locomotion. Here we investigated how common pheasants negotiate visible obstacles with heights from 10 to 50% of leg length. Our goal was to determine the neuro-mechanical strategies used to achieve robust stability, and address whether strategies vary with obstacle height. We found that control of landing conditions was crucial for minimising fluctuations in stance leg loading and work in uneven terrain. Variation in touchdown leg angle (θ(TD)) was correlated with the orientation of ground force during stance, and the angle between the leg and body velocity vector at touchdown (β(TD)) was correlated with net limb work. Pheasants actively targeted obstacles to control body velocity and leg posture at touchdown to achieve nearly steady dynamics on the obstacle step. In the approach step to an obstacle, the birds produced net positive limb work to launch themselves upward. On the obstacle, body dynamics were similar to uniform terrain. Pheasants also increased swing leg retraction velocity during obstacle negotiation, which we suggest is an active strategy to minimise fluctuations in peak force and leg posture in uneven terrain. Thus, pheasants appear to achieve robustly stable locomotion through a combination of path planning using visual feedback and active adjustment of leg swing dynamics to control landing conditions. We suggest that strategies for robust stability are context specific, depending on the quality of sensory feedback available, especially visual input.

  2. Modelling changes in terrain resistance as a component of landform evolution in unstable hill country

    Science.gov (United States)

    Crozier, M. J.; Preston, N. J.

    Accurate modelling of landform evolution in unstable terrain requires some means of determining the frequency and magnitude of landslide occurrence. In many areas, this can be achieved with reference to the potency of the triggering regime and the susceptibility of the terrain. Terrain susceptibility is controlled by inherent geomechanical resistance and topographic conditions which filter the effect of the triggering agent. For a given terrain, susceptibility can be conveniently represented by establishing the triggering threshold required for the occurrence of landslides. Problems are identified in use of thresholds developed from historical and contemporary measurements of landslide activity to predict or postdict landslide activity. Even if all other external controlling factors remain constant, there appear to be event-related temporal shifts in terrain resistance which change the level of the triggering threshold and the occurrence of landslides over time. Mechanisms responsible for this change are proposed and the results of field investigation into geomechanical limiting equilibrium conditions are produced to demonstrate the effects of these mechanisms and the changes in resistance they produce. A conceptual model is presented to place event-related changes in susceptibility into the context of a major phase of landslide-induced soil erosion which has affected New Zealand hill country since European deforestation.

  3. Remote Sensing of Martian Terrain Hazards via Visually Salient Feature Detection

    Science.gov (United States)

    Al-Milli, S.; Shaukat, A.; Spiteri, C.; Gao, Y.

    2014-04-01

    The main objective of the FASTER remote sensing system is the detection of rocks on planetary surfaces by employing models that can efficiently characterise rocks in terms of semantic descriptions. The proposed technique abates some of the algorithmic limitations of existing methods with no training requirements, lower computational complexity and greater robustness towards visual tracking applications over long-distance planetary terrains. Visual saliency models inspired from biological systems help to identify important regions (such as rocks) in the visual scene. Surface rocks are therefore completely described in terms of their local or global conspicuity pop-out characteristics. These local and global pop-out cues are (but not limited to); colour, depth, orientation, curvature, size, luminance intensity, shape, topology etc. The currently applied methods follow a purely bottom-up strategy of visual attention for selection of conspicuous regions in the visual scene without any topdown control. Furthermore the choice of models used (tested and evaluated) are relatively fast among the state-of-the-art and have very low computational load. Quantitative evaluation of these state-ofthe- art models was carried out using benchmark datasets including the Surrey Space Centre Lab Testbed, Pangu generated images, RAL Space SEEKER and CNES Mars Yard datasets. The analysis indicates that models based on visually salient information in the frequency domain (SRA, SDSR, PQFT) are the best performing ones for detecting rocks in an extra-terrestrial setting. In particular the SRA model seems to be the most optimum of the lot especially that it requires the least computational time while keeping errors competitively low. The salient objects extracted using these models can then be merged with the Digital Elevation Models (DEMs) generated from the same navigation cameras in order to be fused to the navigation map thus giving a clear indication of the rock locations.

  4. VIIRS/NPP Moderate Resolution Terrain Corrected Geolocation 6-Min L1 Swath 750m Light V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The Visible Infrared Imaging Radiometer Suite (VIIRS) Moderate Resolution Terrain Correction Geolocation (VNP03MODLL) Version 1 product from the Suomi National...

  5. Cloud, Aerosol, and Complex Terrain Interactions (CACTI) Preliminary Science Plan

    Energy Technology Data Exchange (ETDEWEB)

    Varble, Adam [Univ. of Utah, Salt Lake City, UT (United States); Nesbitt, Steve [Univ. of Illinois, Urbana-Champaign, IL (United States); Salio, Paola [Univ. of Buenos Aires (Argentina); Zipser, Edward [Univ. of Utah, Salt Lake City, UT (United States); van den Heever, Susan [Colorado State Univ., Fort Collins, CO (United States); McFarquhar, Greg [Univ. of Illinois, Urbana-Champaign, IL (United States); Kollias, Pavlos [Stony Brook Univ., NY (United States); Kreidenweis, Sonia [Colorado State Univ., Fort Collins, CO (United States); DeMott, Paul [Colorado State Univ., Fort Collins, CO (United States); Jensen, Michael [Brookhaven National Lab. (BNL), Upton, NY (United States); Houze, Jr., Robert [Univ. of Washington, Seattle, WA (United States); Rasmussen, Kristen [Colorado State Univ., Fort Collins, CO (United States); Leung, Ruby [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Romps, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gochis, David [National Center for Atmospheric Research, Boulder, CO (United States); Avila, Eldo [National Univ. of Cordoba (Argentina); Williams, Christopher [Univ. of Colorado, Boulder, CO (United States); National Center for Atmospheric Research, Boulder, CO (United States)

    2017-02-01

    General circulation models and downscaled regional models exhibit persistent biases in deep convective initiation location and timing, cloud top height, stratiform area and precipitation fraction, and anvil coverage. Despite important impacts on the distribution of atmospheric heating, moistening, and momentum, nearly all climate models fail to represent convective organization, while system evolution is not represented at all. Improving representation of convective systems in models requires characterization of their predictability as a function of environmental conditions, and this characterization depends on observing many cases of convective initiation, non-initiation, organization, and non-organization. The Cloud, Aerosol, and Complex Terrain Interactions (CACTI) experiment in the Sierras de Córdoba mountain range of north-central Argentina is designed to improve understanding of cloud life cycle and organization in relation to environmental conditions so that cumulus, microphysics, and aerosol parameterizations in multi-scale models can be improved. The Sierras de Córdoba range has a high frequency of orographic boundary-layer clouds, many reaching congestus depths, many initiating into deep convection, and some organizing into mesoscale systems uniquely observable from a single fixed site. Some systems even grow upscale to become among the deepest, largest, and longest-lived in the world. These systems likely contribute to an observed regional trend of increasing extreme rainfall, and poor prediction of them likely contributes to a warm, dry bias in climate models downstream of the Sierras de Córdoba range in a key agricultural region. Many environmental factors influence the convective lifecycle in this region including orographic, low-level jet, and frontal circulations, surface fluxes, synoptic vertical motions influenced by the Andes, cloud detrainment, and aerosol properties. Local and long-range transport of smoke resulting from biomass burning as

  6. Terrain Inclination Aided Three-Dimensional Localization and Mapping for an Outdoor Mobile Robot

    Directory of Open Access Journals (Sweden)

    Xiaorui Zhu

    2013-01-01

    Full Text Available A new 3D localization and mapping technique with terrain inclination assistance is proposed in this paper to allow a robot to identify its location and build a global map in an outdoor environment. The Iterative Closest Points (ICP algorithm and terrain inclination-based localization are combined together to achieve accurate and fast localization and mapping. Inclinations of the terrains the robot navigates are used to achieve local localization during the interval between two laser scans. Using the results of the above localization as the initial condition, the ICP algorithm is then applied to align the overlapped laser scan maps to update the overhanging obstacles for building a global map of the surrounding area. Comprehensive experiments were carried out for the validation of the proposed 3D localization and mapping technique. The experimental results show that the proposed technique could reduce time consumption and improve the accuracy of the performance.

  7. Path-following control of wheeled planetary exploration robots moving on deformable rough terrain.

    Science.gov (United States)

    Ding, Liang; Gao, Hai-bo; Deng, Zong-quan; Li, Zhijun; Xia, Ke-rui; Duan, Guang-ren

    2014-01-01

    The control of planetary rovers, which are high performance mobile robots that move on deformable rough terrain, is a challenging problem. Taking lateral skid into account, this paper presents a rough terrain model and nonholonomic kinematics model for planetary rovers. An approach is proposed in which the reference path is generated according to the planned path by combining look-ahead distance and path updating distance on the basis of the carrot following method. A path-following strategy for wheeled planetary exploration robots incorporating slip compensation is designed. Simulation results of a four-wheeled robot on deformable rough terrain verify that it can be controlled to follow a planned path with good precision, despite the fact that the wheels will obviously skid and slip.

  8. Pitted terrains on (1) Ceres and implications for shallow subsurface volatile distribution

    Science.gov (United States)

    Sizemore, H.G.; Platz, Thomas; Schorghofer, Norbert; Prettyman, Thomas; De Sanctis, Maria Christina; Crown, David A.; Schmedemann, Nico; Nessemann, Andeas; Kneissl, Thomas; Simone Marchi,; Schenk, Paul M.; Bland, Michael; Schmidt, B.E.; Hughson, Kynan H.G.; Tosi, F.; Zambon, F; Mest, S.C.; Yingst, R.A.; Williams, D.A.; Russell, C.T.; Raymond, C.A.

    2017-01-01

    Prior to the arrival of the Dawn spacecraft at Ceres, the dwarf planet was anticipated to be ice-rich. Searches for morphological features related to ice have been ongoing during Dawn's mission at Ceres. Here we report the identification of pitted terrains associated with fresh Cerean impact craters. The Cerean pitted terrains exhibit strong morphological similarities to pitted materials previously identified on Mars (where ice is implicated in pit development) and Vesta (where the presence of ice is debated). We employ numerical models to investigate the formation of pitted materials on Ceres and discuss the relative importance of water ice and other volatiles in pit development there. We conclude that water ice likely plays an important role in pit development on Ceres. Similar pitted terrains may be common in the asteroid belt and may be of interest to future missions motivated by both astrobiology and in situ resource utilization.

  9. Pitted terrains on (1) Ceres and implications for shallow subsurface volatile distribution

    Science.gov (United States)

    Sizemore, H. G.; Platz, T.; Schorghofer, N.; Prettyman, T. H.; De Sanctis, M. C.; Crown, D. A.; Schmedemann, N.; Neesemann, A.; Kneissl, T.; Marchi, S.; Schenk, P. M.; Bland, M. T.; Schmidt, B. E.; Hughson, K. H. G.; Tosi, F.; Zambon, F.; Mest, S. C.; Yingst, R. A.; Williams, D. A.; Russell, C. T.; Raymond, C. A.

    2017-07-01

    Prior to the arrival of the Dawn spacecraft at Ceres, the dwarf planet was anticipated to be ice-rich. Searches for morphological features related to ice have been ongoing during Dawn's mission at Ceres. Here we report the identification of pitted terrains associated with fresh Cerean impact craters. The Cerean pitted terrains exhibit strong morphological similarities to pitted materials previously identified on Mars (where ice is implicated in pit development) and Vesta (where the presence of ice is debated). We employ numerical models to investigate the formation of pitted materials on Ceres and discuss the relative importance of water ice and other volatiles in pit development there. We conclude that water ice likely plays an important role in pit development on Ceres. Similar pitted terrains may be common in the asteroid belt and may be of interest to future missions motivated by both astrobiology and in situ resource utilization.

  10. Wind farm layout optimization in complex terrain: A preliminary study on a Gaussian hill

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2014-01-01

    One of the crucial problems for wind farm (WF) development is wind farm layout optimization. It seeks to find the optimal positions of wind turbines (WTs) inside a WF, so as to maximize and/or minimize a single objective or multiple objectives, while satisfying certain constraints. Although...... this problem for WFs in flat terrain or offshore has been investigated in many studies, it is still a challenging problem for WFs in complex terrain. In this preliminary study, the wind flow conditions of complex terrain without WTs are first obtained from computational fluid dynamics (CFD) simulation...... adaptive mechanisms and applied to solve the layout optimization problem of a WF on a Gaussian shape hill. The layout of the WF with a certain number of WTs is optimized to maximize the total power output, which obtained steady improvements over expert guess layouts....

  11. Paleogeography of the northern portion of the Mixteca terrain, southern Mexico, during the Middle Jurassic

    Science.gov (United States)

    Caballero-Miranda, C.; Morán-Zenteno, D. J.; Urrutia-Fucugauchi, J.; Silva-Romo, G.; Böhnel, H.; Jurado-Chichay, Z.; Cabral-Cano, E.

    A preliminary paleogeographic reconstruction of the northern Mixteca terrain in southern Mexico is presented for the Middle Jurassic. The reconstruction is derived from combined analyses of spatial distribution of marine-continental Jurassic sedimentary units, identification of sediment source, and observations based on sedimentary indicators of environment and transport directions, as well as paleomagnetic and anisotropy of magnetic susceptibility (AMS) results. There is an overall agreement between the AMS magnetic fabric results and the sedimentary indicators of current directions and paleogeographic elements. The results suggest a coastline at the south-southwest portion of this terrain, a general transport of fluvial sediments to the south and southwest, and marine influxes from the south. A Pacific margin provenance is supported by the paleomagnetic results for the northern portion of the Mixteca terrain.

  12. An Inter-Comparison Study of Multi- and DBS Lidar Measurements in Complex Terrain

    DEFF Research Database (Denmark)

    Pauscher, Lukas; Vasiljevic, Nikola; Callies, Doron

    2016-01-01

    Wind measurements using classical profiling lidars suffer from systematic measurement errors in complex terrain. Moreover, their ability to measure turbulence quantities is unsatisfactory for wind-energy applications. This paper presents results from a measurement campaign during which multiple...... seems to be more important for turbulence measurements. In summary, the results clearly show the advantages of the ML technique in complex terrain and indicate that it has the potential to achieve significantly higher accuracy in measuring turbulence quantities for wind-energy applications than...... WindScanners were focused on one point next to a reference mast in complex terrain. This multi-lidar (ML) technique is also compared to a profiling lidar using the Doppler beam swinging (DBS) method. First- and second-order statistics of the radial wind velocities from the individual instruments...

  13. Rolling ball algorithm as a multitask filter for terrain conductivity measurements

    Science.gov (United States)

    Rashed, Mohamed

    2016-09-01

    Portable frequency domain electromagnetic devices, commonly known as terrain conductivity meters, have become increasingly popular in recent years, especially in locating underground utilities. Data collected using these devices, however, usually suffer from major problems such as complexity and interference of apparent conductivity anomalies, near edge local spikes, and fading of conductivity contrast between a utility and the surrounding soil. This study presents the experience of adopting the rolling ball algorithm, originally designed to remove background from medical images, to treat these major problems in terrain conductivity measurements. Applying the proposed procedure to data collected using different terrain conductivity meters at different locations and conditions proves the capability of the rolling ball algorithm to treat these data both efficiently and quickly.

  14. A Research on Wind Farm Micro-sitting Optimization in Complex Terrain

    DEFF Research Database (Denmark)

    Xu, Chang; Yang, Jianchuan; Li, Chenqi

    2013-01-01

    turbines’ park coordinates which subject to the boundary and minimum distance conditions between two wind turbines. A Cross Particle Swarm Optimization (CPSO) method is developed and applied to optimize the layout for a certain wind farm case. Compared with the uniform and experience method, results show......Wind farm layout optimization in complex terrain is a pretty difficult issue for onshore wind farm. In this article, a novel optimization method is proposed to optimize the layout for wind farms in complex terrain. This method utilized Lissaman and Jensen wake models for taking the terrain height...... and the wake loss from the upstream turbines into the wind turbine power output calculation. Wind direction is divided into sixteen sections, and the wind speed is processed using the Weibull distribution. The objective is to maximize the total wind farm power output and the free design variables are the wind...

  15. A framework for global terrain classification using 250-m DEMs to predict geohazards

    Science.gov (United States)

    Iwahashi, J.; Matsuoka, M.; Yong, A.

    2016-12-01

    Geomorphology is key for identifying factors that control geohazards induced by landslides, liquefaction, and ground shaking. To systematically identify landforms that affect these hazards, Iwahashi and Pike (2007; IP07) introduced an automated terrain classification scheme using 1-km-scale Shuttle Radar Topography Mission (SRTM) digital elevation models (DEMs). The IP07 classes describe 16 categories of terrain types and were used as a proxy for predicting ground motion amplification (Yong et al., 2012; Seyhan et al., 2014; Stewart et al., 2014; Yong, 2016). These classes, however, were not sufficiently resolved because coarse-scaled SRTM DEMs were the basis for the categories (Yong, 2016). Thus, we develop a new framework consisting of more detailed polygonal global terrain classes to improve estimations of soil-type and material stiffness. We first prepare high resolution 250-m DEMs derived from the 2010 Global Multi-resolution Terrain Elevation Data (GMTED2010). As in IP07, we calculate three geometric signatures (slope, local convexity and surface texture) from the DEMs. We create additional polygons by using the same signatures and multi-resolution segmentation techniques on the GMTED2010. We consider two types of surface texture thresholds in different window sizes (3x3 and 13x13 pixels), in addition to slope and local convexity, to classify pixels within the DEM. Finally, we apply the k-means clustering and thresholding methods to the 250-m DEM and produce more detailed polygonal terrain classes. We compare the new terrain classification maps of Japan and California with geologic, aerial photography, and landslide distribution maps, and visually find good correspondence of key features. To predict ground motion amplification, we apply the Yong (2016) method for estimating VS30. The systematic classification of geomorphology has the potential to provide a better understanding of the susceptibility to geohazards, which is especially vital in populated areas.

  16. Terrain-based Predictive Modeling of a Functional Riparian Corridor in a Coastal Northern California Watershed

    Science.gov (United States)

    Robinson, T.; Davis, J. D.

    2016-12-01

    Riparian corridors and their associated geomorphic landforms (e.g., channels, floodplains, and terraces) and vegetation communities (e.g., forests and wetlands) have been significantly degraded in California, prompting an expansion of efforts to delineate riparian corridors and identify priorities for conservation via deed restrictions and easements. Current techniques to delineate riparian corridors for these purposes include fixed-width buffers based on stream centerlines and digitization of woody vegetation from aerial photos. Although efficient, these delineation methods do not accurately capture the extent of ecologically functional riparian corridors and result in riparian habitat being excluded from conservation efforts while non-riparian is included. From a physical perspective, ecologically functional riparian corridors have widths that vary with topography and ample space for dynamic fluvial geomorphic processes that create and maintain river morphology and vegetation and sustain ecological interactions that extend from the stream channel laterally into upland ecosystems and up- and downstream ecosystems in longitudinal directions. New terrain-based spatial analysis techniques and high-resolution digital terrain data show promise in delineating ecologically functional riparian corridors. In this study, we compare the efficacy of three terrain-based predictors of riparian corridors that have emerged in the literature—elevation above channel, flow accumulation, and distance from channel. The results of each terrain predictor are compared with field-based indicators of the riparian corridor of an alluvial reach of Mark West Creek in Sonoma County, California (a mediterranean climate). Indicators include soil type, fluvial geomorphic landforms, and vegetation. A one-meter digital terrain model from LiDAR (Light Detection and Ranging) supplied by a NASA ROSES grant is used as the base terrain data for spatial analysis. We discuss in detail the use of

  17. TouchTerrain: A simple web-tool for creating 3D-printable topographic models

    Science.gov (United States)

    Hasiuk, Franciszek J.; Harding, Chris; Renner, Alex Raymond; Winer, Eliot

    2017-12-01

    An open-source web-application, TouchTerrain, was developed to simplify the production of 3D-printable terrain models. Direct Digital Manufacturing (DDM) using 3D Printers can change how geoscientists, students, and stakeholders interact with 3D data, with the potential to improve geoscience communication and environmental literacy. No other manufacturing technology can convert digital data into tangible objects quickly at relatively low cost; however, the expertise necessary to produce a 3D-printed terrain model can be a substantial burden: knowledge of geographical information systems, computer aided design (CAD) software, and 3D printers may all be required. Furthermore, printing models larger than the build volume of a 3D printer can pose further technical hurdles. The TouchTerrain web-application simplifies DDM for elevation data by generating digital 3D models customized for a specific 3D printer's capabilities. The only required user input is the selection of a region-of-interest using the provided web-application with a Google Maps-style interface. Publically available digital elevation data is processed via the Google Earth Engine API. To allow the manufacture of 3D terrain models larger than a 3D printer's build volume the selected area can be split into multiple tiles without third-party software. This application significantly reduces the time and effort required for a non-expert like an educator to obtain 3D terrain models for use in class. The web application is deployed at http://touchterrain.geol.iastate.edu/

  18. Salt or ice diapirism origin for the honeycomb terrain in Hellas basin, Mars?: Implications for the early martian climate

    Science.gov (United States)

    Weiss, David K.; Head, James W.

    2017-03-01

    The "honeycomb" terrain is a Noachian-aged cluster of ∼7 km wide linear cell-like depressions located on the northwestern floor of Hellas basin, Mars. A variety of origins have been proposed for the honeycomb terrain, including deformation rings of subglacial sediment, frozen convection cells from a Hellas impact melt sheet, a swarm of igneous batholiths, salt diapirism, and ice diapirism. Recent work has shown that the salt or ice diapirism scenarios appear to be most consistent with the morphology and morphometry of the honeycomb terrain. The salt and ice diapirism scenarios have different implications for the ancient martian climate and hydrological cycle, and so distinguishing between the two scenarios is critical. In this study, we specifically test whether the honeycomb terrain is consistent with a salt or ice diapir origin. We use thermal modeling to assess the stability limits on the thickness of an ice or salt diapir-forming layer at depth within the Hellas basin. We also apply analytical models for diapir formation to evaluate the predicted diapir wavelengths in order to compare with observations. Ice diapirism is generally predicted to reproduce the observed honeycomb wavelengths for ∼100 m to ∼1 km thick ice deposits. Gypsum and kieserite diapirism is generally predicted to reproduce the observed honeycomb wavelengths for ≥ 600-1000 m thick salt deposits, but only with a basaltic overburden. Halite diapirism generally requires approx. ≥ 1 km thick halite deposits in order to reproduce the observed honeycomb wavelengths. Hellas basin is a distinctive environment for diapirism on Mars due to its thin crust (which reduces surface heat flux), low elevation (which allows Hellas to act as a water/ice/sediment sink and increases the surface temperature), and location within the southern highlands (which may provide proximity to inflowing saline water or glacial ice). The plausibility of an ice diapir mechanism generally requires temperatures ≤ 250

  19. Training Revising Based Traversability Analysis of Complex Terrains for Mobile Robot

    Directory of Open Access Journals (Sweden)

    Rui Song

    2014-05-01

    Full Text Available Traversability analysis is one of the core issues in the autonomous navigation for mobile robots to identify the accessible area by the information of sensors on mobile robots. This paper proposed a model to analyze the traversability of complex terrains based on rough sets and training revising. The model described the traversability for mobile robots by traversability cost. Through the experiment, the paper gets the conclusion that traversability analysis model based on rough sets and training revising can be used where terrain features are rich and complex, can effectively handle the unstructured environment, and can provide reliable and effective decision rules in the autonomous navigation for mobile robots.

  20. A BEM approach to validate a model for predicting sound propagation over non-flat terrain

    DEFF Research Database (Denmark)

    Quirós Alpera, Susana; Jacobsen, Finn; Juhl, Peter Møller

    2003-01-01

    A two-dimensional boundary element model for sound propagation in a homogeneous atmosphere above non-flat terrain has been constructed. An infinite impedance plane is taken into account in the Green's function in the underlying integral equation, so that only the nonflat parts of the terrain need....... Sound Vibrat. 223 (1999) 355]. The resulting BEM model, which can handle arbitrary combinations of barriers and hollows, has been used for validating a ray model for various difficult configurations, including combinations of valleys and barriers. (C) 2003 Elsevier Science Ltd. All rights reserved....

  1. A BEM approach to validate a model for predicting sound propagation over non-flat terrain

    DEFF Research Database (Denmark)

    Quirósy Alpera, S.; Jacobsen, Finn; Juhl, P.M.

    2003-01-01

    A two-dimensional boundary element model for sound propagation in a homogeneous atmosphere above non-flat terrain has been constructed. An infinite impedance plane is taken into account in the Green's function in the underlying integral equation, so that only the nonflat parts of the terrain need....... Sound Vibrat. 223 (1999) 355]. The resulting BEM model, which can handle arbitrary combinations of barriers and hollows, has been used for validating a ray model for various difficult configurations, including combinations of valleys and barriers....

  2. Prediction of wind power potential by wind speed probability distribution in a hilly terrain near Bh

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Siraj; Diwakar, Nilesh

    2010-09-15

    Daily wind speed data in metre per second and its direction of flow in degree were recorded from of the India Meteorological Department for a site near the Bhopal Airport for the period of eleven years. The influence of roughness of the terrain, obstacles and topography in terms of contour for the area were also taken into consideration. These data were analysed using WAsP programme and regional wind climate of the area was determined. It is seen from the analysis of the wind speed data and keeping the topographical variation of terrain, exploitable wind speed is experienced at 50 m.

  3. Extraction of oil palm plantations on the undulating terrains in the Borneo using PALSAR Global Mosaic

    Science.gov (United States)

    Tanigaki, Y.; Ishii, R.; Kobayashi, H.; Nagai, S.; Suzuki, R.

    2013-12-01

    Conversions of forests and peat swamps into oil palm plantations might cause decrease of net ecosystem production, change of water stream and loss of biodiversity. Most of the oil plantations in the South East Asia have been expanded in the past decade. For monitoring the distribution and condition of these plantations, the PALSAR Global Mosaic data set (PGM) have been utilized. This PGM is one of the L-Band Synthetic Aparture Radar (SAR) data sets orthorectified and mosaicked (unified). Unlike optical satellite imagery, the L-band SAR is useful especially for cloudy tropic regions. In addition, PGM have high resolution (about 10 m) and contains cross polarization (HV) SAR data which is useful for observation of forest because cross polarization SAR data contain data of the volume scattering which reflect the volume of plant bodies. On the other hand, topographic effect in PGM is not reduced sufficiently because of low resolution of DEM utilized to make PGM. As a result, pixel value of PGM is affected by the highlight effect especially in undulating terrains. These undulating terrains consist of rises which have about 10m height, exist in about 100m horizontal interval and cause striped patterns on SAR images. These patterns result in difficulty in extracting oil palm plantation using SAR imagery in the undulating terrains. However, many papers extracting oil palm plantations didn't show the accuracy of distributions extracted as oil palm plantation in the undulating terrains and thus it isn't clear how well oil palm plantations on the undulating terrains can be extracted. In this study, we carried out a supervised classification and extracted oil palm plantations in the north-west of Borneo Island. The Island is a part of the South East Asia and contains undulating terrains. In this extraction, we used the PGM data, a learning model and the training data made from PGM data, aerial photograph, high resolution optical satellite data and field survey data. After

  4. Polarimetric SAR Terrain Classification Using Polarimetric Features Derived from Rotation Domain

    Directory of Open Access Journals (Sweden)

    Tao Chensong

    2017-10-01

    Full Text Available Terrain classification is an important application for understanding and interpreting Polarimetric Synthetic Aperture Radar (PolSAR images. One common PolSAR terrain classification uses roll-invariant feature parameters such as H/A/a/SPAN. However, the back scattering response of a target is closely related to its orientation and attitude. This frequently introduces ambiguity in the interpretation of scattering mechanisms and limits the accuracy of the PolSAR terrain classification, which only uses roll-invariant feature parameters for classification. To address this problem, the uniform polarimetric matrix rotation theory, which interprets a target’s scattering properties when its polarimetric matrix is rotated along the radar line of sight and derives a series of polarimetric features to describe hidden information of the target in the rotation domain was proposed. Based on this theory, in this study, we apply the polarimetric features in the rotation domain to PolSAR terrain discrimination and classification, and develop a PolSAR terrain classification method using both the polarimetric features in the rotation domain and the roll-invariant features of H/A/a/SPAN. This method also uses both the selected polarimetric feature parameters in the rotation domain and H/A/a/SPAN as input for a Support Vector Machine (SVM classifier and achieves better classification performance by complementing the terrain discrimination abilities of both. Results from comparison experiments based on AIRSAR and UAVSAR data demonstrate that compared with the conventional method, which only uses H/A/a/SPAN as SVM classifier input, the proposed method can achieve higher classification accuracy and better robustness. For fifteen terrain classes of AIRSAR data, the total classification accuracy of the proposed method was 92.3%, which is higher than the 91.1% of the conventional method. Moreover, for seven terrain classes of multi-temporal UAVSAR data, the averaged

  5. Analyse spatiale, évaluation et cartographie du risque glissement de terrain

    OpenAIRE

    Malet, Jean-Philippe; Thiery, Yannick; Maquaire, Olivier; Puissant, Anne

    2006-01-01

    International audience; RÉSUMÉ : Pour évaluer et cartographier le risque « glissement de terrain », les techniques d'analyse spatiale et les technologies SIG sont rarement utilisées. En particulier, aucune étude concerne la cartographie automatique du risque « glissement de terrain » à grande échelle (1:10,000 è), échelle de travail correspondant à la cartographie règlementaire du risque naturel en France. Cet article présente une procédure en trois étapes pour évaluer et cartographier le ris...

  6. Traversable terrain classification for outdoor autonomous robots using single 2D laser scans

    DEFF Research Database (Denmark)

    Andersen, Jens Christian; Blas, Morten Rufus; Andersen, Nils Axel

    2006-01-01

    , curvature, slope, width and invalid data. These are then used to extract road borders, traversable terrain and identify obstacles. Experimental results are shown and discussed. The results were obtained using a DTU developed mobile robot, and the autonomous tests were conducted in a national park......Interpreting laser data to allow autonomous robot navigation on paved as well as dirt roads using a fixed angle 2D laser scanner is a daunting task. This paper introduces an algorithm for terrain classification that fuses seven distinctly different classifiers: raw height, roughness, step size...

  7. Hybrid RANS/LES method for wind flow over complex terrain

    DEFF Research Database (Denmark)

    Bechmann, Andreas; Sørensen, Niels N.

    2010-01-01

    ), and this layer acts as wall model for the outer flow handled by LES. The well-known high Reynolds number two-equation k - turbulence model is used in the RANS layer and the model automatically switches to a two-equation k - subgrid scale stress model in the LES region. The approach can be used for flow over...... the turbulent kinetic energy, whereas the new method captures the high turbulence levels well but underestimates the mean velocity. The presented results are for a relative mild configuration of complex terrain, but the proposed method can also be used for highly complex terrain where the benefits of the new...

  8. Terrain Classification for Outdoor Autonomous Robots using 2D Laser Scans

    DEFF Research Database (Denmark)

    Rufus Blas, Morten; Riisgaard, Søren; Ravn, Ole

    2005-01-01

    Interpreting laser data to allow autonomous robot navigation on paved as well as dirt roads using a fixed angle 2D laser scanner is a daunting task. This paper introduces an algorithm for terrain classification that fuses four distinctly different classifiers: raw height, step size, slope, and ro...... with a department developed Medium Mobile Robot and tests conducted in a national park environment......Interpreting laser data to allow autonomous robot navigation on paved as well as dirt roads using a fixed angle 2D laser scanner is a daunting task. This paper introduces an algorithm for terrain classification that fuses four distinctly different classifiers: raw height, step size, slope...

  9. LINCOM wind flow model: Application to complex terrain with thermal stratification

    DEFF Research Database (Denmark)

    Dunkerley, F.; Moreno, J.; Mikkelsen, T.

    2001-01-01

    LINCOM is a fast linearised and spectral wind flow model for use over hilly terrain. It is designed to rapidly generate mean wind field predictions which provide input to atmospheric dispersion models and wind engineering applications. The thermal module, LINCOM-T, has recently been improved...... to provide reasonably robust results over a range of stability conditions. The results predicted for idealised terrain only are presented here. Meteorological data used to initialise the model are normally obtained from measurements or from outputs from larger scale numerical models. These standard data...

  10. Online 3D terrain visualisation using Unity 3D game engine: A comparison of different contour intervals terrain data draped with UAV images

    Science.gov (United States)

    Hafiz Mahayudin, Mohd; Che Mat, Ruzinoor

    2016-06-01

    The main objective of this paper is to discuss on the effectiveness of visualising terrain draped with Unmanned Aerial Vehicle (UAV) images generated from different contour intervals using Unity 3D game engine in online environment. The study area that was tested in this project was oil palm plantation at Sintok, Kedah. The contour data used for this study are divided into three different intervals which are 1m, 3m and 5m. ArcGIS software were used to clip the contour data and also UAV images data to be similar size for the overlaying process. The Unity 3D game engine was used as the main platform for developing the system due to its capabilities which can be launch in different platform. The clipped contour data and UAV images data were process and exported into the web format using Unity 3D. Then process continue by publishing it into the web server for comparing the effectiveness of different 3D terrain data (contour data) draped with UAV images. The effectiveness is compared based on the data size, loading time (office and out-of-office hours), response time, visualisation quality, and frame per second (fps). The results were suggest which contour interval is better for developing an effective online 3D terrain visualisation draped with UAV images using Unity 3D game engine. It therefore benefits decision maker and planner related to this field decide on which contour is applicable for their task.

  11. Integrating Human Terrain reasoning and tooling in C2 systems

    NARCIS (Netherlands)

    Reus, N. de; Grand, N. le; Kwint, M.; Reniers , F.; Anthonie van Lieburg, A. van

    2010-01-01

    Within an operational staff the ‘core business’ of the Intelligence Cell is to initiate, collect, process, analyze and disseminate relevant information. This Intelligence Preparation of the Environment addresses the environmental evaluation, threat evaluation and results in an integrated overview of

  12. Sensitivity of a carbon and productivity model to climatic, water, terrain, and biophysical parameters in a Rocky Mountain watershed

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S.; Peddle, D.R.; Coburn, C.A.; Kienzle, S. [Univ. of Lethbridge, Dept. of Geography, Lethbridge, Alberta (Canada)

    2008-06-15

    Net primary productivity (NPP) is a key component of the terrestrial carbon cycle and is important in ecological, watershed, and forest management studies, and more broadly in global climate change research. Determining the relative importance and magnitude of uncertainty of NPP model inputs is important for proper carbon reporting over larger areas and time periods. This paper presents a systematic evaluation of the boreal ecosystem productivity simulator (BEPS) model in mountainous terrain using an established montane forest test site in Kananaskis, Alberta, in the Canadian Rocky Mountains. Model runs were based on forest (land cover, leaf area index (LAI), biomass) and climate-water inputs (solar radiation, temperature, precipitation, humidity, soil water holding capacity) derived from digital elevation model (DEM) derivatives, climate data, geographical information system (GIS) functions, and topographically corrected satellite imagery. Four sensitivity analyses were conducted as a controlled series of experiments involving (i) NPP individual parameter sensitivity for a full growing season, (ii) NPP independent variation tests (parameter {mu} {+-} 1{sigma}), (iii) factorial analyses to assess more complex multiple-factor interactions, and (iv) topographic correction. The results, validated against field measurements, showed that modeled NPP was sensitive to most inputs measured in the study area, with LAI and forest type the most important forest input, and solar radiation the most important climate input. Soil available water holding capacity expressed as a function of wetness index was only significant in conjunction with precipitation when both parameters represented a moisture-deficit situation. NPP uncertainty resulting from topographic influence was equivalent to 140 kg C ha{sup -1}{center_dot}year{sup -1}. This suggested that topographic correction of model inputs is important for accurate NPP estimation. The BEPS model, designed originally for flat

  13. Advancing Satellite-Based Flood Prediction in Complex Terrain Using High-Resolution Numerical Weather Prediction

    Science.gov (United States)

    Zhang, X.; Anagnostou, E. N.; Nikolopoulos, E. I.; Bartsotas, N. S.

    2015-12-01

    Floods constitute one of the most significant and frequent natural hazard in mountainous regions. Satellite-based precipitation products offer in many cases the only available source of QPE. However, satellite-based QPE over complex terrain suffer from significant bias that limits their applicability for hydrologic modeling. In this work we investigate the potential of a new correction procedure, which involves the use of high-resolution numerical weather prediction (NWP) model simulations to adjust satellite QPE. Adjustment is based on the pdf matching of satellite and NWP (used as reference) precipitation distribution. The impact of correction procedure on simulating the hydrologic response is examined for 15 storm events that generated floods over the mountainous Upper Adige region of Northern Italy. Atmospheric simulations were performed at 1-km resolution from a state-of-the-art atmospheric model (RAMS/ICLAMS). The proposed error correction procedure was then applied on the widely used TRMM 3B42 satellite precipitation product and the evaluation of the correction was based on independent in situ precipitation measurements from a dense rain gauge network (1 gauge / 70 km2) available in the study area. Satellite QPE, before and after correction, are used to simulate flood response using ARFFS (Adige River Flood Forecasting System), a semi-distributed hydrologic model, which is used for operational flood forecasting in the region. Results showed that bias in satellite QPE before correction was significant and had a tremendous impact on the simulation of flood peak, however the correction procedure was able to reduce bias in QPE and therefore improve considerably the simulated flood hydrograph.

  14. Continuous monitoring of snowpack dynamics in alpine terrain by aboveground neutron sensing

    Science.gov (United States)

    Schattan, Paul; Baroni, Gabriele; Oswald, Sascha E.; Schöber, Johannes; Fey, Christine; Kormann, Christoph; Huttenlau, Matthias; Achleitner, Stefan

    2017-05-01

    The characteristics of an aboveground cosmic-ray neutron sensor (CRNS) are evaluated for monitoring a mountain snowpack in the Austrian Alps from March 2014 to June 2016. Neutron counts were compared to continuous point-scale snow depth (SD) and snow-water-equivalent (SWE) measurements from an automatic weather station with a maximum SWE of 600 mm (April 2014). Several spatially distributed Terrestrial Laser Scanning (TLS)-based SD and SWE maps were additionally used. A strong nonlinear correlation is found for both SD and SWE. The representative footprint of the CRNS is in the range of 230-270 m. In contrast to previous studies suggesting signal saturation at around 100 mm of SWE, no complete signal saturation was observed. These results imply that CRNS could be transferred into an unprecedented method for continuous detection of spatially averaged SD and SWE for alpine snowpacks, though with sensitivity decreasing with increasing SWE. While initially different functions were found for accumulation and melting season conditions, this could be resolved by accounting for a limited measurement depth. This depth limit is in the range of 200 mm of SWE for dense snowpacks with high liquid water contents and associated snow density values around 450 kg m-3 and above. In contrast to prior studies with shallow snowpacks, interannual transferability of the results is very high regardless of presnowfall soil moisture conditions. This underlines the unexpectedly high potential of CRNS to close the gap between point-scale measurements, hydrological models, and remote sensing of the cryosphere in alpine terrain.

  15. Underwater Glider Terrain Relative Navigation for use in Surface Denied Regions

    Science.gov (United States)

    Claus, B.; Bachmayer, R.

    2016-02-01

    Autonomous underwater gliders have proven their utility to gather a wide range of measurements in a challenging environment. Their increasing adoption rates by scientific institutions and government organizations globally are a testament to this fact. However, operational gaps still exist in regions where surface access is denied due the inability of the vehicle to surface and acquire GPS updates to reduce the error of the localization estimates.Prior work by the authors has derived a terrain aided navigation algorithm developed for a Slocum Electric underwater glider. The algorithm makes use of the vehicle's dead-reckoned navigation solution, onboard altimeter and a local digital elevation model (DEM) to compute bounded location estimates independent of surface access. An evaluation of the method was performed through post-processing location estimates from 12 km of field trials in 2010 and 91 km of trials in 2012 which took place in the glacial fjord of Holyrood Arm, Newfoundland, overlapping a previously collected DEM. These results suggested the ability of the algorithm to maintain bounded error location estimates with a RMS error of 33 meters in the 2010 trials and 50 meters in the 2012 trials. These errors are contrasted with a dead-reckoned error of 900 meters in the 2010 trials and 5.5 km in the 2012 trials. These trials were followed by online open loop location estimates in 2014 for which RMS errors of 76 and 32 meters were obtained during two, hour long trials. The dead-reckoned error for these same trials was 190 meters and 90 meters respectively.The preliminary results of this method are promising but have been limited to a single region. To extend the methodology this work examines the suitability of other applicable ice covered regions such as the Antarctic as well as high ship traffic areas such as the Gulf of Mexico through archived glider data. Additional future areas of application include the Chukchi and Beaufort Seas and Davis strait.

  16. Geolocation of man-made reservoirs across terrains of varying complexity using GIS

    Science.gov (United States)

    Mixon, D.M.; Kinner, D.A.; Stallard, R.F.; Syvitski, J.P.M.

    2008-01-01

    The Reservoir Sedimentation Survey Information System (RESIS) is one of the world's most comprehensive databases of reservoir sedimentation rates, comprising nearly 6000 surveys for 1819 reservoirs across the continental United States. Sediment surveys in the database date from 1904 to 1999, though more than 95% of surveys were entered prior to 1980, making RESIS largely a historical database. The use of this database for large-scale studies has been limited by the lack of precise coordinates for the reservoirs. Many of the reservoirs are relatively small structures and do not appear on current USGS topographic maps. Others have been renamed or have only approximate (i.e. township and range) coordinates. This paper presents a method scripted in ESRI's ARC Macro Language (AML) to locate the reservoirs on digital elevation models using information available in RESIS. The script also delineates the contributing watersheds and compiles several hydrologically important parameters for each reservoir. Evaluation of the method indicates that, for watersheds larger than 5 km2, the correct outlet is identified over 80% of the time. The importance of identifying the watershed outlet correctly depends on the application. Our intent is to collect spatial data for watersheds across the continental United States and describe the land use, soils, and topography for each reservoir's watershed. Because of local landscape similarity in these properties, we show that choosing the incorrect watershed does not necessarily mean that the watershed characteristics will be misrepresented. We present a measure termed terrain complexity and examine its relationship to geolocation success rate and its influence on the similarity of nearby watersheds. ?? 2008 Elsevier Ltd. All rights reserved.

  17. Melt and collapse of buried water ice: An alternative hypothesis for the formation of chaotic terrains on Mars

    NARCIS (Netherlands)

    Zegers, T.E.; Oosthoek, J.H.P.; Rossi, A.P.; Blom, J.K.; Schumacher, S.

    2010-01-01

    Chaotic terrains and the associated massive outflow channels are some of the most enigmatic features on Mars. Over hundreds of kilometres of rock units are fractured, tilted, and have subsided, forming chaotic terrain basins (Sharp, 1973). Large quantities of water emanated from these chaotic

  18. Soil and Terrain Database for Argentina, primary data (version 1.0) - scale 1:1 million (SOTER_Argentina)

    NARCIS (Netherlands)

    Dijkshoorn, J.A.; Huting, J.R.M.

    2014-01-01

    The Soil and Terrain database for Argentina primary data (version 1.0), at scale 1:1 million (SOTER_Argentina), was compiled of enhanced soil information within the framework of the FAO's program Land Degradation Assessment in Drylands (LADA). Primary soil and terrain data for Argentina were

  19. 75 FR 76708 - Extension of the Date by Which Youth All-Terrain Vehicles Must Be Tested and Certified

    Science.gov (United States)

    2010-12-09

    ... COMMISSION Extension of the Date by Which Youth All-Terrain Vehicles Must Be Tested and Certified AGENCY... (including importers) of youth all-terrain vehicles (ATVs) must submit sufficient samples of such products to... which youth ATVs must be tested by third party conformity assessment bodies accredited by the Commission...

  20. Soil and Terrain Database for Nepal (version 1.0) - scale 1:1 million (SOTER_Nepal)

    NARCIS (Netherlands)

    Dijkshoorn, J.A.

    2014-01-01

    The Soil and Terrain database for Nepal primary data (version 1.0), at scale 1:1 million (SOTER_Nepal). SOTER_Nepal is generalized from the original Soils and Terrain database of Nepal at scale 1:50,000 compiled by FAO and Nepal's Survey Dept. The SOTER_Nepal database provides generalized