Research On The Plane Projection Method Of The Tilt High Speed Railway

The length accuracy requirement in the projection of the high-speed railway is 1/100000.Gauss projection is usually used in our country,although it meets demands,it has a big disadvantage that it needs a set of projection zone when it is used in railway projection,and that cause a problem that you need multiple independent coordinate system corresponding to every projection zone,and it Increase grate workload.For the reasons given above,we should improve Gauss projection to enlarge control area and decrease projection zone,or find a new projection way to replace Gauss projection.We study the technique of oblique direction projection through Lanzhou–Xinjiang Railway.Based on analyzing the problems occurred in Gauss projection,we try to use oblique Mercator projection to replace Gauss projection so that we can use one projection zone to solve the problems such as multiple projection zones and complex coordinate system transformation,and study length deformation of Mercator projection through project example to check if it can satisfy the accuracy requirement 1/100000,and given the formulas of Mercator projection and its length deformation.And in the original Gauss projection,to reduce the length of the deformation by the Compensated Height projection of Gaussian face.Researches show that Compensating Level Surface modified Gauss Projection can reduce the length of the deformation?And the Mercator projection in the projection of oblique direction high speed railway is able to replace Gauss projection well,and it can reduce projection zoon to one while meet length deformation requirement.Least squares method can be used to determine the optimal oblique Mercator projection neutral position.This paper's results of this study to the tilt direction of high-speed rail projection having a theoretical guidance and reference works.