An evaluation of available digital elevation models (DEMs) for geomorphological feature analysis
A digital elevation model (DEM) is an essential dataset for many land feature analyses, such as geomorphological feature analyses, which are very important for many types of studies. The present study involved the evaluation of five of the most common DEMs and their derived geomorphological features in the Humrat Assahn basin. A 10-m reference DEM was generated for the study area from a contour map produced at the Royal Jordanian Geographic Center (RJGC). In addition, an aerial photography DEM with a 10-m resolution was generated using PCI Geomatica software. Both the second version of the 30-m Advanced Spaceborne Thermal Emission and Reflection Radiometer Global DEM version 2 (ASTER GDEM 2) and a DEM derived from 2000 Google earth (GE) elevation points were evaluated as well. The validation process included a comparison of elevation profiles, the calculation of DEM accuracies and statistics, and the evaluation of some delineated geomorphological features such as hill shade and watershed, which are derivatives of each DEM. The results revealed a strong relationship between the reference DEM and the aerial photo DEM, and it is found that there is a moderate relationship between the reference DEM and the Shuttle Radar Topography Mission (SRTM), GE, and ASTER GDEM 2 DEMs. The root mean square errors (RMSEs) of the aforementioned DEM values were ? 12.526 m, ? 40.411 m, ? 42.332 m, and ? 43.383 m, respectively.
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