Robust cadastral coordinate transformation based on least absolute deviation

Abstract

Robust cadastral coordinate transformation based on least absolute deviation (LAD) is proposed in this paper. Firstly, the 4-parameter coordinate transformation procedures from TWD67 coordinates to TWD97 coordinates were presented. Then, two data sets were used to test the proposed method. The test results show that: (1) based on the simulated data, under certain number of outliers, neither the outliers exist in the TWD67 coordinates, the TWD97 coordinates, nor the TWD67 and TWD97 coordinates, can affect the LAD coordinate transformation accuracies; and (2) based on the real data, further prove that the LAD coordinate transformation is a robust estimation method.