Generation of High Resolution DEM of Gangotri Glacier Using Remote Sensing Techniques on ASTER Imagery

Abstract

Summary The following study proposes a novel method for creation of Digital elevation model (DEM) which can be used to monitor the changes that take place in glaciers and complete the glacier inventory. DEM was created using ASTER stereo images, with Gangotri Glacier being the study area. Data obtained from ASTER Satellite provides Rational Polynomial Coefficient (RPC) which facilitated us in the mapping from object space (longitude, latitude, height) to image space (sample, line). Ground Control Points (GCPs) are crucial to improve the geographic positions predicted by the supplied RPCs. Pan-sharpened Colour composite of bands 5-4-3 obtained from Landsat OLI satellite and SRTM (30 m resolution) DEM was used for collecting uniformly distributed GCPs. Good Image matching of both the stereo pairs was done using Tie Points. ASTER DEM was then generated, following the standard procedure in “ENVI 5.0.” The resultant elevation error, assessed by comparing the elevations derived from SRTM and ASTER was found to be around ±30m. This study will help, further in monitoring temporal Volumetric and Mass changes over the Gangotri region. Our methodology has the potential to quickly produce and verify the DEMs in high mountainous regions efficiently.