摘要：Global Digital Elevation Models (DEMs) have been utilized in various geomatics activities worldwide. Recently, there exist several available DEMs vary significantly in terms of spatial resolution and release dates. This paper examines the reliability of eight recent global DEMs, namely the EarthEnv-D90, SRTM 1, SRTM 3, ASTER, GMTED2010, GLOBE, GTOPO30, and AW3D30, in two study areas in Egypt and Saudi Arabia representing different topography patterns. Known ground control points with measured accurate coordinates and precise elevations have been utilized in evaluating the performance of those DEMs. It has been concluded that such a judgment procedure should not be carried based on a single statistical measure. First, five statistical measures, specifically the range, standard deviation, correlation, kurtosis, and skewness, have been evaluated separately for each DEM’s errors. Then, a new reliability index is introduced based on the weighted average concept. The accomplished results show that global DEMs perform differently in different topography patterns. It has been concluded that the EarthEnv-D90 and SRTM1 models attain high reliability indexes in the Nile delta region that represents a flat topography, while the GMTED2010 and EarthEnv-DEM90 models came in the first places for the second study area, Makkah, which represents mountainous topography.
