GIS-BASED CONVERSION BETWEEN BEIJING 1954 AND XI'AN 1980 COORDINATE SYSTEMS

During geological surveying work, the conversion between coordinate systems is frequently involved. The principle of conversion between Beijing 1954 and Xi,an 1980 coordinate systems is discussed in this paper. In combination with some problems encountered in practical work, two examples are analyzed. Based on the result from "Mining Rights and Field Verification in Liaoning Province", the corrected values of Beijing 1954 and Xi,an 1980 coordinate conversion are obtained for all 1:50 000 maps of Liaoning Province. With analysis on these corrected values, the applicable ranges of commonly used seven-parameter Bursa model and three-parameter coordinate conversion are provided. The procedures and methods of conversion between Beijing 1954 and Xi,an 1980 coordinate systems with MapGIS software are described.