Accuracy Comparison of the Srtm, Aster, Ned, Nextmap® Usa Digital Terrain Model over Several Usa Study Sites

Accurate digital terrain models (DTMs) are necessary for a wide variety applications. National-scale mediumresolution elevation data have been acquired for the conterminous United States under the USGS National Elevation Data (NED; 10 m and 30 m), the Shuttle Radar Topographic Mapping (SRTM; 30 m), and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER; 30 m) programs. Intermap’s STAR technology offers an improvement over the NED and SRTM datasets with its high-resolution (5 m) bare-ground and firstsurface elevation data and coincident orthorectified radar imagery over the conterminous United States and 17 Western European countries. SRTM, ASTER, NED and NEXTMap® elevation data over several study sites across the United States were compared to in-situ barren land elevation measurements and National Geodetic Survey (NGS) verification check points. The range of study sites represent various terrain types (slope range 0 30) and continental environments (arid, semiarid, and temperate). The NEXTMap® DTM received an overall accuracy of 2.94 RMSE for 808 topographic in-situ and NGS VCPs taken on slopes ranging from 028, with one half of those being beneath vegetated canopy and obstructed areas (urban). Lower overall DTM accuracies were achieved by the NED (4.52 m RMSE), SRTM (15.27 m RMSE), and ASTER (18.52 m RMSE). All the DTM data sets’ accuracy vary with land cover categories ranging from 1.24 m – 16.60 m RMSE (Grass/Shrub), 1.53 m – 41.10 m RMSE (deciduous), 3.20 m – 24.76 m RMSE (evergreen), and 2.13 m – 18.81m (mixed forest).