小区域工程测量控制网独立坐标系统选择

Selection of Independent Coordinate System of Independent Coordinate System in Small Area

小区城工程测量控制网可以建立独立坐标系统,但独立坐标系统要建立在国家统一坐标系统的基础上,而且平面控制网的坐标系统应满足测区内投影长度变形不大于2.5cm/km.以西藏某市小区城大比例尺地形图测绘项目为例,以国家等级控制点为起算点,通过成果的投影换代、斜轴投影、选取合适的抵偿高程面相结合的方式,介绍如何选择并建立独立坐标系统的方法.

The small area engineering surveying control network can establish independent coordinate system, but it should be built on the basis of the national unified coordinate system. Moreover, the coordinate system of the plane control network should meet the requirement that the projection length deformation of the survey area is no more than 2.5 cm/km. Taking a large scale topographic mapping project in a small area of Tibet as an example, and taking the state level control point as the starting point, this paper introduces how to select and establish an independent coordinate system by means of the combination of the project generation, oblique axis projection and selection of appropriate compensating level surface