Algorithm Research of Scale Auto- conversion for Coal Mine Ground and Underground Contrast Maps

Coal mine ground and underground contrast maps were generally both 1 : 2 000 and 1 : 5 000 scales, applying to different application requirements. Th e graphics elements of different scales were basically the same, but the trade- offs of expression and content of the map features were different. The traditional method was complicated which required users draw different maps by their own knowledge. Based on the data and functions of Longruan GIS 3. 2 platform, we had posed the i dea that different scale maps could be automatically converted based on the topological relationship of point, line and rarefying of line, symbol layering in this paper. At last, we achieved scale automatic conversion function on GIS platform. The practical application proved the method was good, efficient and helpful for mapping the coal mine ground and underground contrast maps.