Geoinformática e Geoestatística: Uma Visão Geral

Generation and Evaluation of DEM from Cartosat-1 Stereo Data Using Ground Control Points from Topographical Maps

Navatha Y, Venkata Reddy K, Deva Pratap and Sharma SB

Generation and Evaluation of DEM from Cartosat-1 Stereo Data Using Ground Control Points from Topographical Maps

Digital Elevation Model (DEM) is a basic input to find out the terrain characteristics and terrain parameters. It is also used for planning of infrastructural facilities of an area. There are several ways to generate a DEM and with the advances in spatial technologies, it becomes easy to generate a DEM from the satellite data. In the present paper, DEM has been generated using Cartosat-1 satellite stereo data with Ground Control Points (GCPs) taken from Survey of India (SOI) topographical map and mass points that are digitized after block triangulation. The generated DEM has been evaluated with elevation values of Survey of India (SOI) topographical map of the study area. The generated DEM has also been compared with the ASTER DEM of the study area and it is observed that Cartosat-1 extracted DEM shows better results when mapping at large scales. From the DEM quality map, it is seen that 86% pixels identified as excellent to good category and only 16% are identified as isolated to suspicious category. From the comparison of DEM prepared from block triangulation and contours, it is seen that 26% pixels have the elevation variation of less than 5 m and 30% pixels have the elevation variation of 5 m to 10 m. Elevation variation of less than 5m is seen for 23% pixels and 5 m to 10 m is seen for the 51% pixels between the ASTER DEM and DEM prepared from contours. DEM extracted from Cartosat-1 satellite data can be used for planning and implementation of infrastructural facilities, as it require more accurate and detailed terrain variations.