Terrain Datasets Research Articles

Using GIS analytics and social preference data to evaluate utility-scale solar power site suitability

Determining socially acceptable and economically viable locations for utility-scale solar projects is a costly process that depends on many technical, economic, environmental and social factors. This paper presents a GIS-based multi-criteria solar project siting study conducted in the southwestern United States with a unique social preference component. Proximity raster layers were derived from features including roads, power lines, and rivers then overlain with 10 × 10 m raster terrain datasets including slope and potential irradiance to produce a high resolution map showing solar energy potential from “poor” to “excellent” for high potential counties across the southwestern United States. Similar maps were produced by adding social acceptance data collected from a series of surveys showing the potential public resistance to development that can be expected in areas of high solar energy suitability. Applying social preferences to the model significantly reduced the amount of suitable area in each of the selected study areas. The methods demonstrated are expected to help reduce time, money, and resources currently allocated toward finding and assessing areas of high solar power suitability.

Modeling the topography of shallow braided rivers using Structure-from-Motion photogrammetry

Recent advances in computer vision and image analysis have led to the development of a novel, fully automated photogrammetric method to generate dense 3d point cloud data. This approach, termed Structure-from-Motion or SfM, requires only limited ground-control and is ideally suited to imagery obtained from low-cost, non-metric cameras acquired either at close-range or using aerial platforms. Terrain models generated using SfM have begun to emerge recently and with a growing spectrum of software now available, there is an urgent need to provide a robust quality assessment of the data products generated using standard field and computational workflows.To address this demand, we present a detailed error analysis of sub-meter resolution terrain models of two contiguous reaches (1.6 and 1.7km long) of the braided Ahuriri River, New Zealand, generated using SfM. A six stage methodology is described, involving: i) hand-held image acquisition from an aerial platform, ii) 3d point cloud extraction modeling using Agisoft PhotoScan, iii) georeferencing on a redundant network of GPS-surveyed ground-control points, iv) point cloud filtering to reduce computational demand as well as reduce vegetation noise, v) optical bathymetric modeling of inundated areas; and vi) data fusion and surface modeling to generate sub-meter raster terrain models. Bootstrapped geo-registration as well as extensive distributed GPS and sonar-based bathymetric check-data were used to quantify the quality of the models generated after each processing step.The results obtained provide the first quantified analysis of SfM applied to model the complex terrain of a braided river. Results indicate that geo-registration errors of 0.04m (planar) and 0.10m (elevation) and vertical surface errors of 0.10m in non-vegetation areas can be achieved from a dataset of photographs taken at 600m and 800m above the ground level. These encouraging results suggest that this low-cost, logistically simple method can deliver high quality terrain datasets competitive with those obtained with significantly more expensive laser scanning, and suitable for geomorphic change detection and hydrodynamic modeling.

WRF-Fire 산불 연료 · 지형자료 해상도와 지상바람의 연소면적 모의민감도 및 오차 분석연구

This study conducted WRF-Fire simulations in order to investigate sensitivities of the resolution of fire fuel and terrain data sets, and the surface wind to simulated fire area. The sensitivity simulations were consisted of 8 different WRF-Fire runs, each of which used different combination of data sets of fire fuel and terrain with different resolution. From the results it was turned out that the surface wind was most sensitive. The next was fire fuel and then fire terrain. Unfortunately, every run produced too much fire area. In other words no simulations succeeded in simulating such proper fire area so as for the WRF-Fire to be used realistically. It was verified that the errors of fire area from each runs were contributed by 41%, 53%, and 6% from surface wind, fire fuel, and fire terrain, respectively. Finally this study suggested that the selection of Anderson fuel category in the area of interest seemed to be very critical in the performance of WRF-Fire simulations.

Elastic Computing Platform Design Based on Lunar Rover Stereo Vision System

In the second stage of Chinese lunar exploration program, lunar rover will be launched for the moon. Stereo vision system of the lunar rover is used for navigation and exploration. Binocular stereo vision cameras collect stereo image pairs of surrounding environment which are transmitted to ground station then used to reconstruct lunar 3D terrain environment. 112 image pairs are collected at one site and terrain data increases rapidly as the rover explores more unknown area so that sequential process system is difficult to generate 3D terrain environment in time. To solve this problem, an elastic parallel computing platform is designed and built using OpenMP parallel computing framework on a 16-processor shared-memory machine. In this paper, architecture of the elastic computing platform is introduced and experiments based on real terrain datasets show that the maximum speedup of the platform can reach 6.44.

Developing Large High-Resolution Display Visualizations of High-Fidelity Terrain Data

The vehicle terrain measurement system (VTMS) allows highly detailed terrain modeling and vehicle simulations. Visualization of large-scale terrain datasets taken from VTMS provides better insights into the characteristics of the pavement or road surface. However, the resolution of these terrain datasets greatly exceeds the capability of traditional graphics displays and computer systems. Large high-resolution displays (LHRDs) enable visualization of large-scale VTMS datasets with high resolution, large physical size, scalable rendering performance, advanced interaction methods, and collaboration. This paper investigates beneficial factors, implementation issues, and case study applications of LHRDs for visualizing large, high-fidelity, terrain datasets from VTMS. Two prototype visualizations are designed and evaluated with automotive and pavement engineers to demonstrate effectiveness of LHRDs for multiscale tasks that involve understanding pavement surface details within the overall context of the terrain.

Parallel contributing area calculation with granularity control on massive grid terrain datasets

The calculation of contributing areas from digital elevation models (DEMs) is one of the important tasks in digital terrain analysis (DTA). The computational process usually involves two steps in a real application: (1) calculating flow directions via a flow model, and (2) computing the contributing area for each grid cell in the DEM. The traditional algorithm for calculating contributing areas is coded as a sequential program executed on a single processor. With the increase of scope and resolution of DEMs, the serial algorithm has become increasingly difficult to perform and is often very time-consuming, especially for DEMs of large areas and fine scales. In recent years, parallel computing is able to meet this challenge with the development of computer technology. However, the parallel implementation with granularity control, an efficient strategy to reap the best parallel performance and to break the limitation of computing resources in processing massive grid terrain datasets, has not been found in DTA research field. This paper develops a message-passing-interface (MPI) parallel approach with granularity control to calculate contributing areas. According to the proposed parallelization strategy, the parallel D8 algorithm with granularity control is designed as well as the parallel AreaD8 algorithm. Based on the domain decomposition of DEM data, it is possible for each process to process multiple partitions decomposed under a grain size. According to an iterative procedure of reading source data, executing the operator and writing resulting data, the partitions achieve the calculation results one by one in each process. The experimental results on a multi-node cluster show that the proposed parallel algorithms with granularity control are the powerful tools to process the big dataset and the parallel D8 algorithm is insensitive to granularity, while the parallel AreaD8 algorithm has an optimal grain size to reap the best parallel performance.

The Design of Gray Earth: A Monochrome Terrain Dataset of the World

Gray Earth is a new terrain dataset available at Natural Earth (NaturalEarthData. com), a NACIS-sponsored repository of free map data (Kelso 2009, Patterson 2012). Serving as a monochromatic counterpart to the site’s full-color terrain rasters, Gray Earth provides a worldwide depiction of landforms in grayscale. It comes in three resolutions that complement the 1:50and 1:10-million vector data also available at Natural Earth. In addition to a basic version showing features of the Earth’s land surface, visitors can also download deluxe versions that include supplemental ocean fills, bathymetric shading, and major rivers (Figure 1).

Seamless terrain rendering method based on binary tree and GPU

In this paper a Graphic Processing Unit(GPU)-based and seamless method for terrain rendering was proposed.The method utilized binary tree to construct the terrain Level Of Detail(LOD) which was represented by row-column templates.In this method,the elevation data was transformed to elevation-texture and then the elevation-texture was used to extract elevation for rendering by Vertex Texture Fetch(VTF).And the whole process was handled by GPU so that the data accessing efficiency was greatly improved.The force-split method in Real-time Optimally Adapting Meshes(ROAM) was used in this method which solved terrain cracks by limiting the level of adjacent terrain blocks.The TriangleStrip primitive was used for terrain rendering which avoided transferring the same vertices' coordinates of adjacent triangles to GPU.Finally the paper tested the efficiency of the new method by two terrain datasets,and compared the frame rates between Clipmap and the new method.The results show that the new proposed method solves the terrain crack effectively and fulfills the demand of interactive terrain rendering.

Changes in snow accumulation and ablation following the Las Conchas Forest Fire, New Mexico, USA

ABSTRACTSeasonally, snow‐covered forests are a critical source of water in the Western United States and are subject to major disturbances, including fire, harvest, disease and insect‐caused mortality, that have relatively unknown effects on water availability. In this study, we investigated changes in winter season snow accumulation and ablation in a forest following the Las Conchas fire in the Jemez Mountains of New Mexico. We investigated two competing sets of processes that should determine the peak annual snowpack prior to snowmelt: (1) reduced interception by forest canopy results in greater new snow accumulation and (2) increased winter season ablation of the snowpack results in reduced peak snowpack volumes. These processes were evaluated with approximately 800 spatially distributed manual observations of new snow, 1500 manual observations of peak snowpack, and light detection and ranging‐derived snow depth, vegetation and terrain datasets collected prior to the fire. A single snowfall event yielded significantly larger snow depths in the post‐burn area versus the unburned area (p < 0.001), with 25% to 45% interception in the unburned area and near zero in the post‐burn area. Conversely, the peak snowpack depths were significantly larger in the unburned area compared with the post‐burn area (mean of 55 and 47 cm, respectively), despite nearly identical peak snowpacks prior to the fire (72 and 72 cm, respectively). The lack of strong vegetation controls led to less variability at peak snowpack in the post‐burn area and a shift towards topographically controlled variability, caused by differences in elevation and aspect, occurring at larger spatial scales. The unburned area had roughly 10% more water available for melt than the post‐burn area, with winter season ablation reducing snowpacks by nearly 50% prior to melt in the post‐burn area. The relative importance of shortwave radiation to the snowpack energy balance and sublimation suggests that the 10% reductions in peak snow water storage found in these north‐facing areas could be a conservative estimate for winter season ablation following fire. Further work is necessary to assess the role that topography plays in altering water partitioning following forest disturbance and the potential implications for ecological health and downstream water resources. Copyright © 2013 John Wiley & Sons, Ltd.

Automatic path generation for terrain navigation

Navigation in 3D terrain is considered to be a challenging task and requires virtual camera control skills such as zooming, panning and tilting. Novice users can easily get distracted and disorientated which may result in being lost in space. Solutions for the virtual environment exploration problems are still being researched in order to assist users during their journey inside virtual environments. Among these solutions, assisted camera control techniques require viewpoint computation and path planning. This paper introduces a novel approach to navigate over a 3D terrain using best viewpoints. We exploit the concept of Viewpoint Entropy for best view determination and use Greedy N-Best View Selection for visibility calculations. We integrate road network data to extract regions for detailed visibility analysis in subsections of the terrain. In order to connect the calculated viewpoints, we use an evolutionary programming approach for the Traveling Salesman problem. We present the generated tour using a Google Earth framework.The computed and planned viewpoints in our solution reduce human effort when used as starting points for scene exploration or to generate the representative images of the terrain dataset. The proposed framework can be integrated into 3D game engines or urban visualization systems. This integration gives quickly a glimpse or tour of the environment for novice users without the help of prior planning. Furthermore, terrain visibility used together with road network data and an optimization method for final path construction allows the computed path to be used for large urban area reconnaissance and surveillance tasks with aerial vehicles.

OPENWEBGLOBE – AN OPEN SOURCE SDK FOR CREATING LARGE-SCALE VIRTUAL GLOBES ON A WEBGL BASIS

Abstract. This paper introduces the OpenWebGlobe project (

Interactive terrain visualization enables virtual field work during rapid scientific response to the 2010 Haiti earthquake

The moment magnitude (Mw) 7.0 12 January 2010 Haiti earthquake is the fi rst major earthquake for which a large-footprint LiDAR (light detection and ranging) survey was acquired within several weeks of the event. Here, we describe the use of virtual reality data visualization to analyze massive amounts (67 GB on disk) of multiresolution terrain data during the rapid scientifi c response to a major natural disaster. In particular, we describe a method for conducting virtual fi eld work using both desktop computers and a 4-sided, 22 m 3 CAVE immersive virtual reality environment, along with KeckCAVES (Keck Center for Active Visualization in the Earth Sciences) software tools LiDAR Viewer, to analyze LiDAR pointcloud data, and Crusta, for 2.5 dimensional surfi cial geologic mapping on a bare-earth digital elevation model. This system enabled virtual fi eld work that yielded remote observations of the topographic expression of active faulting within an ~75-km-long section of the eastern Enriquillo‐Plantain Garden fault spanning the 2010 epicenter. Virtual fi eld observations indicated that the geomorphic evidence of active faulting and ancient surface rupture varies along strike. Landform offsets of 6‐50 m along the Enriquillo‐ Plantain Garden fault east of the 2010 epicenter and closest to Port-au-Prince attest to repeated recent surface-rupturing earthquakes there. In the west, the fault trace is well defi ned by displaced landforms, but it is not as clear as in the east. The 2010 epi center is within a transition zone between these sections that extends from Grand Goâve in the west to Fayette in the east. Within this transition, between L’Acul (lat 72°40′W) and the Rouillone River (lat 72°35′W), the Enriquillo‐Plantain Garden fault is un defi ned along an embayed low-relief range front, with little evidence of recent surface rupture. Based on the geometry of the eastern and western faults that show evidence of recent surface rupture, we propose that the 2010 event occurred within a stepover that appears to have served as a long-lived boundary between rupture segments, explaining the lack of 2010 surface rupture. This study demonstrates how virtual reality‐based data visualization has the potential to transform rapid scientifi c response by enabling virtual fi eld studies and real-time interactive analysis of massive terrain data sets.

바운딩 박스 세분화를 통한 지형 렌더링의 가속화

최근의 3D게임이나 가상현실을 위한 지형 시각화 응용에서는 사실적인 장면을 렌더링 하기 위해 고화질 영상을 실시간에 제공하는 GPU기반의 광선투사법을 이용한다. 이 방법은 지형데이터의 크기가 증가할수록 샘플링 해야 하는 텍셀의 개수가 증가하기 때문에 렌더링 속도가 저하된다. 이러한 문제점을 해결하기 위해서 본 논문에서는 GPU에서 사진트리를 기반으로 수행되는 바운딩 박스 세분화를 이용하여 빈 공간이 제거된 바운딩 박스를 생성하고 이를 이용하여 광선투사법을 가속화하는 방법을 제안한다. 이 방법은 각 광선마다 빈 공간 도약을 위해 트리를 탐색하여 중복된 탐색연산을 수행해야 했던 기존의 방법과 달리 바운딩 박스를 이용하여 탐색 연산을 단 1번만 수행하도록 하여 수행속도를 가속화 하였다.

Ecogeomorphic expressions of an aspect‐controlled semiarid basin: I. Topographic analyses with high‐resolution data sets

ABSTRACTUnderstanding vegetation effects on hydrogeomorphic processes requires detailed studies at the catchment scale using high‐resolution topographic data. We perform topographic analyses in a semiarid basin in central New Mexico with opposing north and south facing slopes. Utilizing a set of terrain metrics, we explore the impact of topographic resolution and quality from three digital elevation models (DEMs): (1) Interferometric Synthetic Aperture Radar (10 m); (2) differential Global Positioning System (4 m); and (3) Light Detection And Ranging (LiDAR, 1 m). The sequentially improved terrain data sets progressively reveal topographic and geomorphic differences in north and facing hillslopes associated with vegetation contrasts. For example, we found less frequent fluvial erosion in the more mesic, north facing slope with a juniper‐grass ecosystem as compared with a more xeric, south facing slope with a desert shrubland. Furthermore, the high‐resolution LiDAR data also revealed weakly steeper south facing slopes, contradicting previous work with coarser topographic products. A sensitivity analysis revealed that hillslope diffusion occurs in north facing ecosystems because of relatively higher slope, whereas fluvial erosion in the south facing ecosystem is a result of large contributing areas. The use of LiDAR data also discriminates statistically between different sediment transport regimes in the north and south facing slopes because of different dominant factors. Improvements in the definition of ecogeomorphic properties from LiDAR point to the need for high‐resolution DEMs for assessing vegetation–hydrogeomorphic interactions at the catchment and hillslope scales. Copyright © 2011 John Wiley & Sons, Ltd.

Development of a Seamless Topographic / Bathymetric Digital Terrain Model for Tampa Bay, Florida

This applications paper presents the methods used to create a seamless topobathy digital terrain model (DTM) at 50-foot resolution intended to support hurricane storm surge modeling in Tampa Bay, Florida. Lidar, bathymetry, and various breakline data were integrated using the Terrain Data Set structure in ArcGIS ® . The use of the Terrain Data Set structure allowed for embedding large data sets (such as lidar points) and archiving them after DTM creation while maintaining topographic analysis capabilities. The bathymetric data, natively referenced to Mean Sea Level (MSL), were converted to North American Vertical Datum of 1988 (NAVD88) using an inverse distance weighted average offset from the three nearest NOAA tidal benchmark stations; results of this conversion were within 6.1 centimeters of those produced by NOAA VDatum software in a quality control test area. This methodology can therefore be used in coastal regions of other countries.

Delineation of Management Zones for Southern Root-Knot Nematode using Fuzzy Clustering of Terrain and Edaphic Field Characteristics

Management zones (MZs) for southern root-knot nematode (RKN) from the integration of terrain (TR) and edaphic (ED) field features might facilitate variable rate nematicide applications. This study was conducted on 11 coastal plain fields in the USA. The relationships between RKN populations and five soil ED and TR attributes (apparent soil electrical conductivity [shallow (ECa-s) and deep (ECa-d)], elevation (EL), slope (SL), and changes in bare soil reflectance) were analyzed using canonical correlation. Using two ED and TR data sets, canonical predictors were used for zone delineation. Although the results showed that the zones with RKN population above the RKN field average were associated with the lowest values of ECa-s, ECa-d, normalized difference vegetation index (NDVI), and SL with respect to field average values, zone segregation was enough using ECa-s and ECa-d data. The results suggest the potential for using soil properties to identify RKN risk zones.

Study of the Hydric Erosion Area using GIS

In this paper we build a geographical information s ystem used to study the hydric erosion of Chinteni area from Cluj County. The geo-database of our GIS contain information about vegetation, soil profiles characteristics and soil moisture for the interest sites. The digital terrai n model was obtained from terrain dataset that was build fr om geo-database. The area affected by water erosion was predicted using spatial analysis.

Extraction of drainage networks from large terrain datasets using high throughput computing

Advanced digital photogrammetry and remote sensing technology produces large terrain datasets (LTD). How to process and use these LTD has become a big challenge for GIS users. Extracting drainage networks, which are basic for hydrological applications, from LTD is one of the typical applications of digital terrain analysis (DTA) in geographical information applications. Existing serial drainage algorithms cannot deal with large data volumes in a timely fashion, and few GIS platforms can process LTD beyond the GB size. High throughput computing (HTC), a distributed parallel computing mode, is proposed to improve the efficiency of drainage networks extraction from LTD. Drainage network extraction using HTC involves two key issues: (1) how to decompose the large DEM datasets into independent computing units and (2) how to merge the separate outputs into a final result. A new decomposition method is presented in which the large datasets are partitioned into independent computing units using natural watershed boundaries instead of using regular 1-dimensional (strip-wise) and 2-dimensional (block-wise) decomposition. Because the distribution of drainage networks is strongly related to watershed boundaries, the new decomposition method is more effective and natural. The method to extract natural watershed boundaries was improved by using multi-scale DEMs instead of single-scale DEMs. A HTC environment is employed to test the proposed methods with real datasets.

Seamless patches for GPU-based terrain rendering

In this paper we present a novel approach for interactive rendering of large terrain datasets. Our approach is based on subdividing a terrain into rectangular patches at different resolutions. Each patch is represented by four triangular tiles that are selected form different resolutions, and four strips which are used to stitch the four tiles in a seamless manner. Such a scheme maintains resolution changes within patches through the stitching strips, and not across patches. At runtime, these patches are used to construct a level-of-detail representation of the input terrain based on view-parameters. A selected level of detail only includes the layout of the patches and their boundary edges resolutions. The layout includes the location and dimension of each patch. Within the graphics hardware, the GPU generates the meshes of the patches by using scaled instances of cached tiles and assigns elevation for each vertex from cached textures. Since adjacent rectangular patches agree on the resolution of the common edges, the resulted mesh does not include cracks or degenerate triangles. Our algorithm manages to achieve quality images at high frame rates while providing seamless transition between different levels of detail.

Automatic target tracking on multi-resolution terrain

We propose a high-performance path planning algorithm for automatic target tracking in the applications of real-time simulation and visualization of large-scale terrain datasets, with a large number of moving objects (such as vehicles) tracking multiple moving targets. By using a modified Dijkstra’s algorithm, an optimal path between each vehicle-target pair over a weighted grid-presented terrain is computed and updated to eliminate the problem of local minima and losing of tracking. Then, a dynamic path re-planning strategy using multi-resolution representation of a dynamic updating region is proposed to achieve high-performance by trading-off precision for efficiency, while guaranteeing accuracy. Primary experimental results showed that our algorithm successfully achieved 10 to 96 frames per second interactive path-replanning rates during a terrain simulation scenario with 10 to 100 vehicles and multiple moving targets.