公共点分布对坐标转换精度的影响

摘要

In order to calculate the transformation of Cartesian coordinates, we need to know the two sets of co ordinates of the common points, select different common points to establish the corresponding error equation and ob tain the 7-parameters or 13-parameters of the transformation. We made the research on comparing estimated points calculated by transformation parameters with designed points in outer-space and inner-space around these common points through the simulation of 165 survey points in 11 rows and 15 columns of two sets coordinates. Taking the Euclid distance of the two sets of points as the basic surface fitting data to establish the surface model for calculating accuracy and with modified Shepard' s method, we have abtained some general distribution law about the accuracy of calculating coordinate points.%空间直角坐标转换需要两套坐标系中公共点的三维坐标值,选取不同的公共点,列立相对应的误差方程求解转换七参数或者十三参数.通过模拟1 1行15列一共165个测量点在两个不同测站中的坐标,分别选择线性、矩形以及三角形的公共点不同分布位置,以及不同数量的公共点,研究利用其求出的坐标转换参数解算外围以及内部点坐标与理论坐标对比,并以其点位差的欧氏距离作为拟合曲面数据,利用改进的Shepard差值模型建立解算精度的曲面模型,得出其解算点位坐标精度的分布规律.