Accuracy Assessment of the Digital Elevation Model, Digital Terrain Model (DTM) from Aerial Stereo Pairs and Contour Maps for Hydrological Parameters

Abstract

In this study, some of the widely used data for elevation models were compared based on hydrological parameters such as slope, aspect, flow direction, and slope length and steepness factor (LS factor). The study considers the comparison among ASTER GDEM, SRTM DEM, topographic maps, and aerial photography at 430239 predetermined tests points. Bilinear interpolation technique was used to interpolate the data at these testing points. The result shows the digital elevation model (DEM) from topographic maps has relatively higher vertical accuracy (RMSE = 5.40 m), compared to ASTER GDEM (7.10 m) and SRTM DEM (15.07 m), while comparing with digital surface model (DSM) from stereo pairs. For validation, we used 47 ground control points (GCPs) using GPS. The results show the vertical accuracy are relatively higher for DSM (RMSE = 1.11 m), followed by DEMs from topographic maps (4.10 m), ASTER GDEM (7.36 m), and SRTM DEM (12.22 m). The DSM matches closely with the result of topographic DEM in case of slope, LS factor curves, aspect, and flow direction. The result with ASTER DEM matches better than results with SRTM data in all the parameters but both of them show poor match with the results from DSM data.