Abstract
Accuracy and quality of DEM are of a great interest for a wide range of applications. In this study, quality of ASTER GDEM and SRTM DEMs were assessed in comparison with DGPS measurements. Impact of DEM resolution upon the accuracy of terrain representation and topographic attributes was also discussed. The study deduced that vertical error has a strong effect on error propagation and this highly obvious in higher elevations as the absolute standard error (SE) ranges between is ±0 - 2.5 and ±0 - 2.4 m for ASTER GDEM and SRTM respectively. This is reflected on slope and aspect as the vertical errors increase and uncertainty is relatively high in flat and low areas. Error propagation in low lands influenced drainage extraction and resulted in isolated and truncated water courses.
Highlights
Digital Elevation Models (DEMs) provide a full 3d perspective-view of an elevation surface
ASTER GDEM and Shuttle Radar Topography Mission (SRTM) DEMs are less accurate than the reference data
We assessed the quality of ASTER GDEM (30 m) and SRTM (90 m) in comparison with in situ Differential Global Positioning System (DGPS) elevation data to reveal its influence on the first derivatives topographic attributes, topographic representation, and the unconstrained derivatives stream networks in a relatively low relief area
Summary
Digital Elevation Models (DEMs) provide a full 3d perspective-view of an elevation surface. The main objective of this work is to assess the quality of ASTER GDEM (the Advanced Spaceborne Thermal Emission and Reflection Radiometer) and SRTM DEMs (Shuttle Radar Topography Mission) in comparison with in situ DGPS (Differential Global Positioning System) elevation data. This would reveal the impact of DEM resolution upon the accuracy of terrain representation and topographic attributes in a relatively low relief area. The results would be valuable to determine the appropriate DEMs for a particular application, improve topographic attributes and drainage extraction, and contribute to the previous works concern the assessment of ASTER GDEM and SRTM DEMs quality
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