Evaluation of the Accuracy of Open-Source DEMs using GPS Data

The DEM is often required for flooding or drainage modeling, land use studies, and geological other applications. A variety of DEMs, such as the Advanced Space Thermal Emission Radiometer (ASTER GDEM) Radar Topography Mission (SRTM) are currently available to public free charge. However, these DEMs remain a representation reality, which requires, before any application, their evaluation using high-precision reference data. objective this study assess quality two ASTER GDEM SRTM, in Morocco. methodology adopted validation based on approaches: internal external validation. first consists comparison versions each product with other. This processing showed that version 2 3 (1 arcsecond) best SRTM respectively. For second validation, vertical precision evaluated by 3551 GPS control points. overall accuracy attests ″ RMSE mean square error 8.17 10.15 respectively compared elevation These values lowest products, confirms SRTM. An in-depth analysis data v2, shows presence outliers associated slope, degradation performance increase slope.