Quality Assessment of Openly Accessible Fused EarthEnv-DEM90 DEM and its comparison with MERIT DEM using Ground Control Points for Diverse Topographic Regions

Currently, many of the practical engineering and environmental applications require a digital elevation model (DEM) as an important scientific input causing variations in the quality of the results in an application depending on the accuracy of the DEM. The availability of fused or assimilated DEMs at global scale is a recent development strengthening the topographic studies and modeling of related phenomenon. Openly accessible EarthEnv-DEM90 is generated by fusion of ASTER GDEM2 and CGIAR-CSI v4.1 (SRTM 90m) products using rigorous techniques for enhanced quality under a collaborative project of NASA known as EarthEnv project. Whereas the other publicly available Multi-Error-Removed Improved-Terrain (MERIT) DEM is the product generated by Dai Yamazaki (University of Tokyo) using SRTM3 v2.1 and AW3D-30m v1 along with supplementary datasets available in different regions of the globe and primarily focusing it for global hydrodynamic modeling. In this study, EarthEnv-DEM90 and MERIT DEM are evaluated using ground control points (GCPs) acquired through differential global positioning system (DGPS) at three experimental sites with varied landforms and consequent topography. The resulting DEM statistics can assist an application scientist in selection of a suitable fused DEM products with improved accuracy for specific applications in comparison to individual DEM products. Mean error (ME), Mean absolute error (MAE) and root mean square errors (RMSE) were computed and revealed that MERIT DEM performs better in plains of Kendrapara site with RMSE as 4 m. However the EarthEnv-DEM90 achieves better accuracy in moderate topography at Jaipur site and rugged topography at Dehradun site with RMSE of 3.05m and 6.55m respectively.