COMPARATIVE EVALUATION OF DIGITAL ELEVATION MODEL BASED ON ELEVATION
DATA AND TERRAIN ATTRIBUTES LEADING TO THEIR VALIDATION
Abstract
Digital Elevation Model (DEM) is the 3D-representation of terrain
surface in the discrete form and a standard tool to examine the
hydrological and research application related to terrain
characterization, landscape and water resources management. It helps in
identifying physical features of an area, watershed delineation and
stream network generation. However, several issues related to DEM’s
accuracy is the utmost concern for researchers. The present study is
based on the comparative studies of DEMs viz., Cartosat-1, SRTM, ALOS
and ASTER having the same spatial resolution of 30m each, under two
different categories of elevation data and topographic attributes. The
vertical accuracy of DEMs is examined by using ground control points as
a reference level of elevation generated from topographic map. Analysing
different sources of error in the DEMs, the RMSE and MAE based
validation of elevation suggests that Cartosat-1 shows relatively high
vertical accuracy (RMSE=45.2 & MAE=7.7) and ASTER shows the least
(RMSE=60.5 & MAE=34.6). The grid size, spatial variation and vertical
accuracy of DEM are among the prime attribute of data sources to
determine the variation in basin morphometry. The study area shows a
gradually undulating topography with 5 th order drainage network. An
inference can be made out of research study that the mean elevation
values of ALOS, SRTM, Cartosat-1 are relatively lower than ASTER whereas
differences in stream parameters are also observed.