Digital Topographic Mapping With Two Different Scales Using GPS And GIS On Adindan Sudan Datum

ABSTRACT The geodetic data used in the production of the topographical base map for any area in Sudan were observed and computed by the classical system related to the local datum Adindan of Clarke 1880 ellipsoid. At this time there are satellite receivers used in geodetic observations where the data produced by the satellite systems are referenced to the geocentric datum The World Geodetic System WGS. Now a days The Global Positioning System was replacing the classical local system which was based on Adindan Sudan datum. This paper describes a technique for evaluation the planimetric accuracy of 100000 and 25000 scale maps produced by Sudan Survey Department SSD. The techniques are based on direct observation of ground control points using Trimble 5700 GPS receivers and arithmetic transformation algorithms. A set of 8 Ground Control Points GCPs has been selected inside the study area. The coordinates of all points have been observed by the GPS receiver and their corresponding values have been derived from maps based on the GIS Techniques. The area of the base - maps scale 1 100000 and 1 25000 bounded by jebelawlia to Elsheikh Eltieb south-North and Jebel Madaha to the University of Khartoum west-east was plotted by the analytical plotter BC-2 and scanned by the Scan Plus III 4000T and manipulated by ARC INFO ESRL-GIS software to check the coordinate values of 8-points using both Adindan Sudan and WGS-84 datums. Statistical analysis shows that both GIS transformation and GPS processing produce the same planimetric accuracy.