Analysis of Constructing 3-Dimensional Virtual Scene Technique Based on DEM

2011 ◽  
Vol 271-273 ◽  
pp. 404-409
Author(s):  
Xiao Gen Li ◽  
Zhi Quan Huang ◽  
Tong Jiang ◽  
An Ming Wang
Keyword(s):  
High Resolution ◽  
Spatial Data ◽  
Geographical Information ◽  
Long Distance ◽  
Virtual Scene ◽  
3 Dimensional ◽  
Reservoir Volume ◽  
Factors Analysis ◽  
Digital Elevation ◽  
Elevation Model

High resolution DEM(Digital Elevation Model, DEM) is created based on original CAD terrain map (one reservoir as example). Then the article offers precision analysis、topographic factors analysis、visibility analysis、reservoir volume and submerging acreage computing. Then adopting GeoVRML technique is to implement the functions of WebGIS 、visualization and query of computing result、graph data visualization and reservoir region virtual scene roaming etc. The system implements deep administrative levels information diged and long-distance visualization expression. The result shows on the basic high resolution DEM to realize 3-Dimensional Visualization Analyse and calculation functions and compress the spatial data to release these data in the WebGIS(Web Geographical Information System, WebGIS) as well as.

Line of Sight Analysis 

2021 ◽  
Author(s):  
Emily Law ◽  
Natalie Gallegos ◽  
Shan Malhotra
Keyword(s):  
High Resolution ◽  
Solar System ◽  
High Gain ◽  
Line Of Sight ◽  
Time Intervals ◽  
Ground Station ◽  
Points Of Interest ◽  
Digital Elevation ◽  
Initial Release ◽  
Elevation Model

<p>The Line of Sight (LoS) is one of the latest tools to join the analytics suite of tools for the Solar System Treks (https://trek.nasa.gov) portals.  The LoS tool provides a way to compute visibility between the entities in our solar system. More concretely, this utility searches for windows of communication or a “line of sight” between any two entities. Entities include orbiters, rovers, planetary bodies, ground stations, and other topographical locations. In addition to establishing communications between the two entities, the tool also takes into account local terrains of the entities in question.</p> <p>The software seeks to answer questions about establishing communications between a rover and an orbiter, or an orbiter to a ground station. In mission planning, LoS can be used to determine possible traverses for a rover that must maintain communications with a lander, or find time intervals of communication to an orbiter when a rover or lander are near an obstructing surface feature such as a crater rim or mound. Computations can be even more granular and lines of sight can be computed between mission instruments, thus allowing to ask questions such as “Is the High Gain Antenna on a rover visible from an orbiter?”</p> <p>The initial release of the software focuses on the lunar surface and the LRO spacecraft. Users can ask whether a topographical location on the moon is visible from the orbiter or a discrete set of ground stations on Earth. The tool uses NAIF SPICE and various mission kernels for computing planetary geometries. LoS also uses high resolution Digital Elevation Model (DEM) to model the terrain surrounding the points of interest. In-house software is used to convert high resolution DEMs into a format compatible with the tool. Users can provide their own DEMs to model the terrain on different topographical locations to use for their own computations.</p>

scholarly journals A High-Resolution Gravimetric Geoid Model for Kuwait Using the Least-Squares Collocation

2022 ◽  
Vol 9 ◽  
Author(s):  
Hamad Al-Ajami ◽  
Ahmed Zaki ◽  
Mostafa Rabah ◽  
Mohamed El-Ashquer
Keyword(s):  
High Resolution ◽  
Least Squares ◽  
Geopotential Model ◽  
Gravimetric Geoid ◽  
Least Squares Collocation ◽  
Geoid Model ◽  
Terrestrial Gravity ◽  
Digital Elevation ◽  
Elevation Model ◽  
Gps Leveling

A new gravimetric geoid model, the KW-FLGM2021, is developed for Kuwait in this study. This new geoid model is driven by a combination of the XGM2019e-combined global geopotential model (GGM), terrestrial gravity, and the SRTM 3 global digital elevation model with a spatial resolution of three arc seconds. The KW-FLGM2021 has been computed by using the technique of Least Squares Collocation (LSC) with Remove-Compute-Restore (RCR) procedure. To evaluate the external accuracy of the KW-FLGM2021 gravimetric geoid model, GPS/leveling data were used. As a result of this evaluation, the residual of geoid heights obtained from the KW-FLGM2021 geoid model is 2.2 cm. The KW-FLGM2021 is possible to be recommended as the first accurate geoid model for Kuwait.

scholarly journals Reconstructing Pre-Industrial Long Distance Roads in a Hilly Region in Germany, Based on Historical and Archaeological Data

2017 ◽  
Vol 1 (2) ◽  
pp. 642-660 ◽  
Author(s):  
Irmela Herzog
Keyword(s):  
Cross Sections ◽  
Lidar Data ◽  
Long Distance ◽  
Early 19Th Century ◽  
Digital Elevation ◽  
Hilly Region ◽  
Local Accuracy ◽  
Cost Paths ◽  
Elevation Model ◽  
The One

The aim of this contribution is on the one hand to map pre-industrial long distance roads located in a hilly region east of Cologne, Germany, as exactly as possible and on the other hand to assess the accuracy of least-cost approaches that are increasingly applied by archaeologists for prehistoric road reconstruction. Probably the earliest map covering the study area east of Cologne dates back to 1575. The map is distorted so that rectification is difficult. But it is possible to assess the local accuracy of the map and to transfer the approximate routes to a modern map manually. Most of the area covered by the 1575 map is also depicted on a set of more accurate maps created in the early 19th century and a somewhat later historical map set (ca. 1842 AD). The historical roads on these rectified historical maps close to the approximate roads were digitized and compared to the outcomes of least-cost analysis, specifically least-cost paths and accessibility maps. Based on these route reconstructions with limited accuracy, Lidar data is checked to identify remains of these roads. Several approaches for visualizing Lidar data are tested to identify appropriate methods for detecting sunken roads. Possible sunken roads detected on the Lidar images were validated by checking cross sections in the digital elevation model and in the field.

scholarly journals Assessing Optimal Digital Elevation Model Selection for Active River Area Delineation Across Broad Regions

2021 ◽  
Author(s):  
Shizhou Ma ◽  
Karen Beazley ◽  
Patrick Nussey ◽  
Chris Greene
Keyword(s):  
High Resolution ◽  
Digital Elevation Model ◽  
Smoothing Algorithm ◽  
Processing Efficiency ◽  
Spatial Approach ◽  
Digital Elevation ◽  
Elevation Data ◽  
Computer Based ◽  
Lidar Dem ◽  
Elevation Model

Abstract The Active River Area (ARA) is a spatial approach for identifying the extent of functional riparian area. Given known limitations in terms of input elevation data quality and methodology, ARA studies to date have not achieved effective computer-based ARA-component delineation, limiting the efficacy of the ARA framework in terms of informing riparian conservation and management. To achieve framework refinement and determine the optimal input elevation data for future ARA studies, this study tested a novel Digital Elevation Model (DEM) smoothing algorithm and assessed ARA outputs derived from a range of DEMs for accuracy and efficiency. It was found that the tested DEM smoothing algorithm allows the ARA framework to take advantage of high-resolution LiDAR DEM and considerably improves the accuracy of high-resolution LiDAR DEM derived ARA results; smoothed LiDAR DEM in 5-meter spatial resolution best balanced ARA accuracy and data processing efficiency and is ultimately recommended for future ARA delineations across large regions.

scholarly journals Geodetic work at the archaeological site Tell el-Retaba

2018 ◽  
Vol 17 (2) ◽  
pp. 65-80
Author(s):  
Eva Stopková
Keyword(s):  
Spatial Data ◽  
Statistical Modelling ◽  
Archaeological Site ◽  
The North ◽  
Digital Elevation ◽  
North Eastern ◽  
Elevation Model ◽  
Modern Technologies

The paper summarizes the geodetic contribution for the Slovak team within the joint Polish-Slovak archaeological mission at Tell el-Retaba in Egypt. Surveying work at archaeological excavations is usually influenced by somewhat specific subject of study and extreme conditions, especially at the missions in the developing countries. The case study describes spatial data development according to the archaeological conventions in order to document spatial relationships between the objects in excavated trenches. The long-term sustainability of surveying work at the site has been ensured by detailed metadata recording. Except the trench mapping, Digital Elevation Model has been calculated for the study area and for the north-eastern part of the site, with promising preliminary results for further detection and modelling of archaeological structures. In general, topographic mapping together with modern technologies like Photogrammetry, Satellite Imagery, and Remote Sensing provide valuable data sources for spatial and statistical modelling of the sites; and the results offer a different perspective for the archaeological research.

scholarly journals An Improved Method Constructing 3D River Channel for Flood Modeling

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 403 ◽  
Author(s):  
Pengbo Hu ◽  
Jingming Hou ◽  
Zaixing Zhi ◽  
Bingyao Li ◽  
Kaihua Guo
Keyword(s):  
High Resolution ◽  
River Channel ◽  
Hydrodynamic Process ◽  
River Channels ◽  
Section Data ◽  
Terrain Model ◽  
Digital Elevation ◽  
Hydrodynamic Processes ◽  
Hermite Spline ◽  
Elevation Model

The high-resolution topography is very crucial to investigate the hydrological and hydrodynamic process. To resolve the deficiency problem of high resolution terrain data in rivers, the Quartic Hermite Spline with Parameter (QHSP) method constructing the river channel terrain based on the limited cross-section data is presented. The proposed method is able to not only improve the reliability of the constructed river terrain, but also avoid the numerical oscillations caused by the existing constructing approach, e.g., the Cubic Hermite Spline (CHS) method. The performance of the proposed QHSP method is validated against two benchmark tests. Comparing the constructed river terrains, the QHSP method can improve the accuracy by at least 15%. For the simulated flood process, the QHSP method could reproduce more acceptable modeling results as well, e.g., in Wangmaogou catchment, the numerical model applying the Digital Elevation Model (DEM) produced by the QHSP method could increase the reliability by 18.5% higher than that of CHS method. It is indicated that the QHSP method is more reliable for river terrain model construction than the CHS and is a more reasonable tool investigating the hydrodynamic processes in river channels lacking of high resolution topography data.

scholarly journals Mapping glaciers in Jotunheimen, South-Norway, during the "Little Ice Age" maximum

2009 ◽  
Vol 3 (2) ◽  
pp. 231-243 ◽  
Author(s):  
S. Baumann ◽  
S. Winkler ◽  
L. M. Andreassen
Keyword(s):  
Little Ice Age ◽  
18Th Century ◽  
Field Measurements ◽  
Geographical Information ◽  
Ice Age ◽  
Inventory Data ◽  
Digital Elevation ◽  
Remote Sensing Techniques ◽  
Southern Norway ◽  
Elevation Model

Abstract. The maximum glacier extent during the "Little Ice Age" (mid 18th century AD) in Jotunheimen, southern Norway, was mapped using remote sensing techniques. Interpretation of existing glaciochronological studies, analysis of geomorphological maps, and own GPS-field measurements were applied for validation of the mapping. The length of glacier centrelines and other inventory data were determined using a Geographical Information System (GIS) and a Digital Elevation Model. "Little Ice Age" maximum extent for a total of 233 glaciers comprising an overall glacier area of about 290 km2 was mapped. Mean length of the centreline was calculated to 1.6 km. Until AD 2003, the area and length shrank by 35% and 34%, respectively, compared with the maximum "Little Ice Age" extent.

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