Research On Applying The Public Version Of Topographic Map To Geological Map

Entering the21st century, one of the most significant changes about geological works that have occurred in the developed countries is the highly promoted geo-information service. Large and medium scaled geological maps, as important carriers of geo-information, not only have great value in geological studies, like the basic geological survey, evaluation of mineral resource, groundwater exploration, engineering survey and investigation and assessment of geological environment, but also have made a great contribution to the construction of socio-economic.Due to restrictions on classified geographical base map, the large and medium scaled geological maps are severely constrained to be used in geological works and the national economic construction. There are many decipherment methods of maps, such as random interference, projection transformation, delete or integrity elements, graphics passivation, etc. Based on these or other unpublished methods, the State Bureau of Surveying and Mapping issued the public version of the1250000topographic maps in2010, which could be prepared for the indicative tourist map or other maps without special accuracy, a relative question is posed as:Whether we can apply the public version of topographic map to1250000geological map? By investigation and analysis, the findings are:1. There are many methods of converting data in ArcGIS format to MapGIS format, direct conversion with the format of SHAPEFILE will result to incorrect topological relation, conversion with the format of Maplnfo may cause the loss of data, while conversion with the format of EOO only will bring the loss of property data. Therefore, by using EOO as the intermediate format and conversion with Label Point, a new method is proposed in this paper, which can realize both the integrity and the accuracy of the topology and properties.2. The key techniques of decipherment for applying the public version of1:250000geological map to studies of geological map 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 can be used in the geological map of viewing and showing needs, establishing geo-tourism maps and other applications of low precision.