Application Analysis of Double Projection in High-Speed Railways Surveying

The controllable range of projection area of the independent coordinates in Gauss Projection which is being used in the High-Speed Railways Surveying presently is too small,so much trouble has been brought in construction.The theory,method and computational process of Slope Mercator Projection along railways are presented after longitude and latitude has been projected on the spherical surface.The feasibility of that in the high-speed railway surveying is analyzed through the experiment data.This method is much more appropriate than Gauss Projection which is being adopt by some construction enterprises in the High-Speed Railways Surveying.