Developments in Digital Mapping from Indian Space Borne Line Scanner Imagery: IRS-1C to Cartosats

The capability of IRS-1C mission of ISRO to acquire imagery of Earth’s surface from multiple orbits to form a stereo pair creates a possibility to recreate the terrain topography and to indulge in digital topographic mapping from space borne line scanner imagery. The scientific exercises leading to use of IRS-1C stereo imagery, specifically development of algorithms and software for assimilating orbit and attitude data sets in photogrammetric relations are summarized in this review paper. Further developments in this direction attributed to conceptualization, design and operational exploitation of Cartosat-1 as a dedicated cartography mission are summarized. A number of technologies like stereo strip triangulation for working with long strips, parametric modeling of image to ground relations through rational polynomial coefficients and for obtaining relative undulations without the use of ground control points developed for Cartosat-1 and other missions of Cartosat series are summarized. Brief description of some large scale operational solutions for extracting three-dimensional elevation model from Cartosat-1 data like CartoDEM, SAPHIRE, Karnataka GIS framework is provided. Some future possibilities are explored.