COMPARISON OF VARIOUS DEMS FOR HEIGHT ACCURACY ASSESSMENT OVER DIFFERENT TERRAINS OF INDIA

In this paper, the height accuracy of various DEMs such as TanDEM-X Global DEM, newly released TanDEM-X 90 m DEM, TanDEM-X ascending or descending DEM, SRTM 30 m, 90 m DEMs, provisional version of the NASADEM, and the aerial LiDAR DEM are assessed over three different Indian terrains. The test sites deal with flat terrain, flat terrain with forest cover and hilly terrain conditions. The accuracy is assessed by computing statistics of the elevation difference between the reference data (ICESat or GPS) and other DEMs. The RMSE for TanDEM-X Global DEMs is less than the mission specification of 10 m. The RMSE over flat terrain (Bihar) is between 1.43 and 5.34 m. For KWLS (flat forested terrain) it ranges from 5.16 to 7.54 m, and for the rugged Himalayan test site Manali the RMSE ranges from 7.41 to 17.15 m. The provisional version of the NASADEM shows better vertical accuracy than the existing SRTM DEMs.