Comparative accuracy analysis of DEMs generated from descending and ascending orbit TerraSAR-X data

Determining the terrain structure of the Earth, a dynamic planet, creating a Digital Elevation Model (DEM) of some parts, and keeping them up to date, are basic necessities for human beings. In this research, DEMs produced using ascending (TRXASC) and descending (TRXDSC) orbit data pairs obtained from the current TerraSAR-X satellite data, and Terra World (TW) DEM (created with the help of data acquired by TanDEM-X), were subjected to point-based accuracy analysis. Standard deviations of the grid point elevation values were calculated using 43,750 digitally-produced grid points, within the study area (5.5 8.5 km2), using different statistical methods. For the accuracy analysis, a 5-metre resolution DEM, created from the aerial photogrammetry technique of the national authority, General Directorate of Mapping (HGM), was used as the DEM basemap. Grid points are also examined according to two basic classes (slope classes and CORINE classes). The deficiency of prior studies using CORINE classes in this context, the preference for segmented-multiple subclasses used for slope classes, and the re-accuracy analysis of all statistical analyses, eliminating the gross error points, significantly contributed to the research with original findings.