Impact of terrain slope and aspect on radargrammetric DEM accuracy

This paper shows results of digital elevation models (DEMs) generated from various RADARSAT stereopairs (fine, standard, extended) over three different topographic study sites (flat-to-rolling, rolling-to-mountainous, mountainous-to-steep) using 3-D parametric modeling developed at the Canada Centre for Remote Sensing (CCRS) and an automated image matching method. Reference topographic DEMs were first used to compute terrain slope and aspect and then to evaluate the accuracy of the stereo-derived DEMs as a function of the slopes and aspects. The DEM accuracy was almost linearly correlated with the terrain slope, with the larger errors in the steepest slopes. In addition, the stronger the stereo radar geometry, the more heterogeneous the DEM is. For the aspect, the best and worse results generally occurred in the foreslopes and backslopes, respectively, and there is no specific trend in the azimuth. Finally, the more pronounced the relief, the higher the correlation between the elevation accuracy and the aspect is and the larger the variations of the elevation accuracy are. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved.