Geomorphometry of Cerro Sillajhuay (Andes, Chile/Bolivia): Comparison of Digital Elevation Models (DEMs) from ASTER Remote Sensing Data and Contour Maps

Abstract Digital elevation models (DEMs) are increasingly used for visual and mathematical analysis of topography, landscapes and landforms, as well as modeling of surface processes. To accomplish this, the DEM must represent the terrain as accurately as possible, since the accuracy of the DEM determines the reliability of the geomorphometric analysis. For Cerro Sillajhuay in the Andes of Chile/Bolivia two DEMs are compared: one derived from contour maps, the other from a satellite stereo‐pair from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). As both DEM procedures produce estimates of elevation, quantative analysis of each DEM was limited. The original ASTER DEM has a horizontal resolution of 30 m and was generated using tie points (TPs) and ground control points (GCPs). It was then resampled to 15 m resolution, the resolution of the VNIR bands. Five parameters were calculated for geomorphometric interpretation: elevation, slope angle, slope aspect, vertical curvature, and tangential curvature. Other calculations include flow lines and solar radiation. Although elevations are too low above 5000 m asl., the ASTER DEM offers reliable results when analyzing the macro‐ and mesorelief, and for mapping at medium scales (1:100,000 to 1:50,000).