Satellite Imagery (LANDSAT) for Reconnaissance Scale Natural Resource Mapping in Western Sudan

Abstract

This study examines the potential usefulness of multi-spectral imagery obtained from the LANDSAT 1 earth orbiting satellite, as a base for reconnaissance scale natural resource mapping in the Sahelian and Savanna zones of Western Sudan. The study is carried out in two parts and covers two adjacent areas of Southern Darfur Province. The first part is a comparative analysis of the accuracy of a land system, geomorphology and soils map, compiled from the manual interpretation of bulk processed colour composite LANDSAT imagery, with that of a similar thematic map of the same area compiled from the interpretation of medium scale aerial photography and ground survey. Methods of image interpretation, data collection and map compilation for both maps are presented, and the objectives of reconnaissance survey and methods of measuring map accuracy are reviewed. Accuracy is measured by comparing the areas occupied by similarly classified mapping units using a standard technique, and by examination and measurement of boundary shape and coincidence using two new methods. Measurements are carried out by manual and digital means. LANDSAT image characteristics of various natural resource features and their equivalent characteristics on aerial photographs are examined in detail. In the second part of the study, reconnaissance scale resource maps of 55,000 km2? of Darfur were compiled from the interpretation and ground checking of LANDSAT imagery in one year. A practical methodology was devised for using satellite imagery in the field that was tailored to the needs and resources generally available in the African Sahelian and Savanna regions.