地图数字化数据质量控制的抗差模型

Robust model of data quality control in map digitizing

对于数字化过程中产生的系统误差,采用函数模型(多项式)拟合进行纠正,对于异常误差采用抗差估计;当粗差污染率较高时,采用高崩溃污染率拟合初值辅以IGGⅢ方案迭代抗差解。最后以一幅具体的数字化地图为例,分别用最小二乘拟合和高崩溃污染率抗差拟合进行了分析比较,并给出了内外检核精度。

A functional model (polynomial) is employed to fit the systematic errors and the robust estimation is applied to controling the effects of outliers. A mixed method, using the median principle to get the preliminary model parameters and then using the IGGⅢ scheme for iterative calculation, is proposed in order to ensure the reliability of the statistics and the rejection region. A practical digital map is used to test the approaches presented in this paper, and the least squares estimation and high breakdown point robust external are carried out. Their internal precision and external accuracy are presented and compared.