地图数字化数据坐标变换的相关性分析

将用于求定地图数字化坐标转换参数的已知点的地面坐标和数字化坐标都当作观测值，用随有参数的条件平差求定转换参数，对采用4个已知点、9个已知点分别进行相似与仿射变换进行了分析，计算了格网点之间的相关系数，进一步分析了格网点间相关系数的分布规律，对转换后的坐标相关性进行了讨论。

Coorelation Analysis of Coordinate Conversion for Digitized Data

This paper discusses the correlation of digitized map coordinates,and to analyze the digitized coordinate data and the errors strictly,adopts adjustment of condition equations with unknowns to solve coordinate conversion parameters.It applies simulating conversion and affine conversion and analyzes the correlation of coordinates conversed by using four known points and nine known points separately.This paper also discusses the distributing rules of the correlation of the grid points.The discussion shows that the x and y coordinates of the same points are not correlative after coordinate translation,but correlation exists in the x and y coordinates of the different points.The number of the known points and the translating manner by which the conversion parameters were drawn determines the correlation of every point.The square error by using nine known points is smaller than that by using four known points after simulating conversion,when the knows points are the same.The precision of ground coordinate after conversion in affine conversion is lower than that in simulating conversion.With the calculating methods adopted in this paper, the value of the correlation changed from -0.235 3 to 0.542 3 ,which shows that the correlation of the coordinate conversion can not be ignored,and the error analyse should be made on the basis of correlation.