Topographic mapping of arid and semi-arid areas in the Red Sea region from stereo space imagery

This paper presents the results of a series of geometric accuracy tests of stereo space images carried out over various sites in the Red Sea region in the context of topographic mapping of the area. These include tests of the planimetric and elevation accuracies of MOMS-02 along-track scanner images and of MC and LFC photographs conducted over test sites in Sudan. Besides these tests, further tests have been carried out to validate the the DEM and orthophotograph produced from an MC stereo-pair of part of the Red Sea Hills in Sudan. In the Badia area of North East Jordan, a special high accuracy test field has been established based on a network of ground control points fixed by Differential GPS. This has been used to create a very large DEM and orthoimage mosaic for the area using five SPOT Level 1B stereo-pairs. The results of extensive tests of the accuracy of point determination and of the DEM, contours and orthoimages created for the Badia Project are given. The final conclusion is that the use of stereo space imagery for topographic mapping in the Red Sea region can produce useful results provided that the limitations in the accuracy of the elevations derived from such images are recognised. However the main deficiencies lie in the extent of the detail and the information content that can be extracted from present day space imagery.