Research Of Large-scale Line Project Coordinate System

The establishment of an appropriate coordinate system is the premise of the line project,establishment of a scientific and rational coordinate system must take into account various factors , this paper analyzed the projection deformation and method of establishing independent coordinate systems for line projects,the main works are as follows:(1)Study on the Gauss projection and Oblique Mercator projection,analysis of the impact of the projection distortion factors and method of correction.(2)Study on the theory of independent coordinate syastem,discussed the processes of establishing of local independent coordinate system,as well as discussed method of conversion between national coordinates system and independent coordinate system,and then focuses on the analysis of the nature and character of several regional Reference ellipsoid.(3)Study on characteristics of an independent coordinate system of the line project,discusses some methods of establishing independent coordinate system for the line project.(4)Based on VC platform,writed a coordinate transformation program,The program can realize coordinate transformation between national coordinates system and independent coordinate system when using different regional ellipsoid,and then examined the accuracy of regional ellipsoid,at last,established an independent coordinate system for a line project in the light of actual conditions combined with TGO software, and discussed its application and rationality.