نتایج جستجو برای: digital elevatiom model dem

تعداد نتایج: 2373347  

2012
M. Huber A. Wendleder B. Wessel

The TanDEM-X mission will derive a global digital elevation model (DEM) with satellite SAR interferometry. Two radar satellites (TerraSAR-X and TanDEM-X) will map the Earth in a resolution and accuracy with an absolute height error of 10m and a relative height error of 2m for 90% of the data. In order to fulfill the height requirements in general two global coverages are acquired and processed....

2015
D. Shen J. Wang X. Cheng S. Ye

The rapid progress of lidar technology has made the acquirement and application of high-resolution digital elevation model (DEM) data increasingly popular, especially in regards to the study of floodplain flow. However, highresolution DEM data pose several disadvantages for floodplain modeling studies; e.g., the data sets contain many redundant interpolation points, large numbers of calculation...

2012
Zhong Lu Hyung-Sup Jung Lei Zhang Wonjin Lee Chang-Wook Lee Daniel Dzurisin

An accurate digital elevation model (DEM) is a critical data set for characterizing the natural landscape, monitoring natural hazards, and georeferencing satellite imagery. The ideal interferometric synthetic aperture radar (InSAR) configuration for DEM production is a single-pass two-antenna system. Repeat-pass single-antenna satellite InSAR imagery, however, also can be used to produce useful...

2008
Peter F. Fisher

One of the most widely available procedures packaged with CIS for the analysis of a Digital Elevation Model (DEM) is the identification of the viewable area, or the viewshed. The elevations recorded in the DEM do, however, contain error, and the USGS, for example, publishes a Root Mean Squared Error (RMSE) for each DEM. Research reported here assesses the uncertainty of locations being within a...

2007
Khizar Hayat William Puech Gilles Gesquière Marc Chaumont

The use of aerial photographs, satellite images, scanned maps and digital elevation models necessitates the setting up of strategies for the storage and visualization of these data in an interactive way. In order to obtain a three dimensional visualization it is necessary to map the images, called textures, onto the terrain geometry computed with Digital Elevation Model (DEM). Practically, all ...

1997
Chris A. Glasbey

Synthetic aperture radar SAR images are notoriously dii-cult to interpret. Segmentation is simpliied if a digital map is available, to which the image can be registered. Also, registration is simpliied if a digital elevation model DEM is available. In this paper it is shown that, if a DEM is unavailable, it can be estimated by minimising an energy functional consisting of a measure of agreement...

1997
Georgy L. Gimel'farb Robert M. Haralick

Abstrac t . A two-stage approach is discussed for reconstructing a dense digital elevation model (DEM) of the terrain from multiple pre-calibrated images taken by distinct cameras at different time under various illumination. First, the terrain DEM and orthoimage are obtained by independent voxel-based reconstruction of the terrain points using simple relations between the corresponding image g...

2001
Jonas Nelson

This contribution presents the different processes applied to a wide area DEM (DigitalElevations Model) in a region in the South of Venezuela, that was obtained by means ofsingle-pass airborne SAR interferometry. Taking into account the well-known SARtechnology limitations, the applied SAR interferometric processing as well as the flightmission constraints, different filtering a...

2001
J. F. Kirby W. E. Featherstone Jon Kirby Will Featherstone

Large gradients, when calculated by a first-difference method, have been detected in the 9 arc-second National Digital Elevation Model (DEM) of Australia released by the Australian Surveying and Land Information Group. Gradient values implied by the mean elevations in the DEM between adjacent grid cells of up to 74° have been observed, most notably in Australia’s more mountainous regions in the...

2017
Anna Petrasova Helena Mitasova Vaclav Petras Justyna Jeziorska

Background: New technologies for terrain reconstruction have increased the availability of topographic data at a broad range of resolutions and spatial extents. The existing digital elevation models (DEMs) can now be updated at a low cost in selected study areas with newer, often higher resolution data using unmanned aerial systems (UAS) or terrestrial sensors. However, differences in spatial c...

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