一种优化高精度曲面建模的DEM构建方法

A method of optimizing HASM for DEM construction

针对当前高精度曲面建模方法在基于高程散点构建DEM过程中存在形态失真的问题,提出一种顾及地表形态变化特征的模型优化方法。通过局部计算区域的坐标系旋转,重新构建了计算格网点周围点的高程之间的约束方程关系。该研究采用理论数学曲面和实地高程采样数据进行精度验证实验,结果表明,基于优化后的高精度曲面建模方法构建的DEM在平均绝对值误差、误差最大值、均方根误差等误差指标上相对反距离加权、普通克里格和样条插值等经典插值方法均有明显改善。此外通过山体阴影等方式进行比较分析,表明优化后的方法构建的DEM具有更高的形态精度。

According to the problem that there exists obvious form error of the OEMs generated by high Accuracy surface modeling ( HASM), this paper put forward a new way to improve this model considered the variation characteristics of surface in local area. The improved model rebuilds the constraint equations between the computing grids and their neighbor grids through rotating the coordinate system in local area. Theoretical mathematical surface and field sampling data were used for accuracy verification in this research. and the analysis results show that the improvement HASM got a significant accuracy advantage compared with the previous model and other classical interpolation models,such as distance inverse weight. ordinary kriging, and Spline method. Further analysis from the view of terrain shadows and comparison of contours indicate that the improvement model's OEMs has better consistency with the approximate surface morphology than the previous HASM and Spline method.