Topographical Mapping at 1:50,000 Scale from Satellite Imagery using CARTOSAT-1

Abstract

High-resolution stereo imaging satellites are a valuable tool for topographic mapping and map updating. Cartosat-1 2.5 meter GSD stereo images were used by “Institut National de Cartographie et de Télédétection” (INCT), Algeria, in collaboration with the Space Application Centre, ISRO, India, in order to map an area of interest situated in the north western side of Algeria at 1:50,000 scale which has never been mapped since the colonial era. This paper presents an effective methodology, which starts from the data preparation and ground control points collection using Differential GPS survey to map creation. Within this project, Cartosat-1 stereo images limitations and potentialities in topographical mapping were assessed. The developed process has allowed us to produce three toposheets of 15’x15’. Although, filed verification has demonstrated that some punctual, linear and surface features could neither be extracted, nor interpreted, mapping at this scale using Cartosat-1 stereo images is possible. However, it requires more time in field survey comparing to the classical mapping process where aerial photos are used.