A tentative discussion on the application of the public version of 1：250 000 topographic map to 1∶250 000 geological map

Abstract：Due to the confidentiality of the geographical base map, the application of the 1∶250 000 geological map to geological task and economic development is being excessively curbed at present. National Administration of Surveying, Mapping and Geoinformation in 2010 issued the public version of the 1∶250 000 topographic maps. As a public use to the publication, it can be prepared for the indicative tourist map and other maps whose accuracy is not strictly required. This paper, based on a study of applying the public version of 1∶250 000 topographic map to 1∶250 000 geological map, has analyzed the involved key techniques of the workflow which includes data format conversion, coordinate system and projection transformation, geographical elements replacement, as well as the topological register analysis, processing, and map decoration. The result has non-directional errors between 200 to 500 meters, and hence it can provide geological map view of low precision, but the application of the result to actual geological work remains somewhat impractical.