Inventorying Environmental Resources - Paradigm Shift In Large Scale Topographic Surveys And Mapping Using high resolution Satellite Images

Abstract

The aerial photographs have been the conventional workhorse for large scale topographic surveys and mapping. The advancement of space based imaging technology in the last decade has brought revolutionary changes in large scale surveys and mapping activities by way of facilitating high resolution images of ≤1 m from satellites such as IKONOS, CARTOSAT, QUICKBIRD, GEOEYE, WORLDVIEW etc. in Optical Infrared class. Although the airborne microwave systems like Geosar is particularly useful in perpetually cloud covered areas in tropical rain forest belts, and other virgin, inaccessible areas of the planet. This has made serious impact on the mapping community and gradually these images are making inroads as a substitute for aerial photographs in large scale map making domain. The increased need of producing more and more maps at large scale using satellite images vastly increased the number of mapping professionals. Most of these professionals are not aware of important issues in map making except for professionals in specialized national mapping organizations like for example ‘Survey of India’ in India. Under this background an attempt is made in this paper to discuss various issues in large scale mapping using high resolution images. The issues addressed include the geometric fidelity, the adequacy of information content, and the elevation information extraction capability of these images.