|
Abstract Research purposes： In the railway control surveying of the high-altitude areas, the side of control network will have a greater length of the projection length distortion. If the control network is established over the national coordinates in the region, the deformation of the length of the railway construction can not meet the requirements of precision control network, which will have a great effect on the coordinates stakeout of line construction survey and breakthrough measurement. Therefore, a reasonable length of the evaluation and treatment of deformed projection of the results of coordinates, and the establishment of high-altitude areas to control the construction of the railway network has become an important part of engineering control surveying in the area.
Research conclusions: In the high altitude control surveying of the railway construction , distortion of reductions of elevation is mainly in the length deformation. So , it is the best choice to select the level surface with compensation used as plane of projection,and build an independent coordinates system based on the orthomorphic projection 3°bands. The method is simple conversion, furthermore, the result of calculated coordinates is very close to the coordinates in the original coordinate system of national unity. It is helpful for the link between inside and outside of the surveying area. If the line length has a wide span from east to west, and when the center of the surveying area is far from the central meridian, we should consider selecting” any local projective stripes" or other methods.
|
2008, Vol. 25 
