Extraction of High Resolution DEM from Cartosat-1 Stereo Imagery using Rational Math Model and Its Accuracy Assessment for a Part of Snow Covered NW-Himalaya

Abstract

This paper reports the experiments carried out for extraction of DEMs from Cartosat-1 stereo imagery using stereo correlation technique for Manali region. The focus of this paper was to assess the accuracy of extracted DEM with respect to DGPS observations, DEM generated from digitized contours of Survey of India (SoI), 1:50,000 scale topographic map(converted to ellipsoidal height using egm2008 geoid model) as well as well-known freely available DEMs ASTER GDEM and SRTM. The vertical accuracy of Cartosat-1 DEMs was analysed with DGPS derived ground control points. The relative vertical accuracy (root mean square error; RMSE) of Cartosat-1 DEM with DGPS control points was ±9.6 m. The RMSE with the topographic DEM was found to be ±10.6 for 22 spot heights and ±10.8 m for 6,458,800 checkpoints. The relative vertical accuracy assessment is more important than the absolute vertical accuracy assessment. The result of relative accuracy assessment of DEMs with respect to field measurement of DGPS points and reference DEMs shows Cartosat-1 DEM is more accurate when compared to ASTER DEM, SoI Topographic DEM, and SRTM DEM for Manali region.