DEM建模方法的研究与实践

Study and Practice of DEM Generation

在分析移动曲面拟合与加权平均算法特点的基础上,提出以移动曲面拟合法为主、加权平均法为辅两者相结合的方法,使它们能够相互取长补短,从而解决大区域DEM建模中存在的问题。对接边处的误差可以进行误差改正并用样条函数对其重建使其光滑。结合5种地貌类型的1∶5万地形图数据进行试验,用中误差对试验结果进行评估和分析,得出该方法在丘陵地区的建模误差最小、效果较好,为今后大区域3维建模提供一种更为精确和合理的方法。

In this paper, constructing DEM was discussed based on rectangular grid. A method was provided which combined moving surface fitting with distance-weighted to build large area DEM based on analyzing their characteristic. It could learn from other＇ s strong points to offset one＇ s weakness. So some difficulties of building large area DEM was solved. The error of boundary where combining moving surface fitting with distanceweighted could be analyzed and the heights of boundary was corrected. In allusion to smoothing of DEM bicubic spline or B-spline was used to build DEM again in boundary. At the same time, some experiments was made with five relief-map of 1 ： 50 000 map data. The results were analyzed and evaluated with mean square error. Error of hill DEM generated by the method was the least according to experiment data error of five geomorphy. A more accurate and reasonable method was offered for large area DEM generation.