Accuracy and relevance of Digital Elevation Models for Geomatics applications A case study of Makkah Municipality, Saudi Arabia

Several geomatics applications depend on utilizing Digital Elevation Models (DEMs), such as geomorphologic applications of watershed management and flood hazard determination. Additionally, DEMs play a crucial role in geodetic applications, particularly for the determination of topographic effects in quasigeoid modelling. This study aims to investigate the accuracy performance of several global and national DEMs in order to define the suitability of them in engineering applications in Kingdom of Saudi Arabia (KSA). Two global DEMs have been exploited, namely the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topographic Mission (SRTM3), along with two national DEMs, belong to the center of research excellence in Hajj and Omrah, with 5 and 10 meter resolution. A dataset of 200 firstorder Global Positioning System (GPS) ground control points, that covers the Makkah (Mecca) metropolitan area in the western region of KSA, has been compiled and employed to judge the accuracy of all DEMs in a Geographic Information Systems (GIS) environment. The attained results showed that the 5meter resolution national DEM is the most accurate one, that produces mean height difference and standard deviations equal 0.01 ± 2.95 m respectively. That national DEM is more accurate by factors of 3 and 2 over the global ASTER and SRTM3 DEMs respectively. Guidelines have been drawn to apply each DEM in geodetic, topographic mapping, and geomorphologic studies in KSA.