Oblique Mercator Projection and Its Application to Control Network for High Speed Railway

Foundation and rail construction must meet higher accuracy for high-speed railway, in order to effectively control projection distance deformation of a GPS control network and reduce the number of projection zone for the east-west highspeed railways, this paper discusses the processing method for the oblique Mercator projection to be applied to develop uniform plane coordinate system by the basic theoriessuch as ellipsoid transformation, projection from ellipsoid to sphere and spherical cylindrical projection. Through a practical engineering example analysis, we show that the oblique Mercator projection can control the length deformation and meet the 10ppm length deformation per kilometer for control network of nonballasted-track and 25ppm for ballast track, and avoid the divisions of too many projection zones. Comparing withnormal Gaussian projection the oblique Mercator projectionhas more superiorities on the east-west high-speed railway andother route engineering control networks.