一种改进的移动曲面拟合DEM插值方法

An Improved DEM Interpolation Method for Surface Moving Fitting

针对传统曲面移动拟合法中定权方式仅以采样点与待插点的距离作为权重,而忽略采样点方向性和分布对DEM插值精度的影响问题,将Shepard加权模型引入曲面移动拟合法中进行分区定权,并在此基础上对采样点的方向性和分布进行约束,提出改进的曲面移动拟合插值方法。以湖南城市学院玉壶山作为研究对象,利用线性内插法、自然邻点插值法、曲面移动拟合法和本文方法对采样点数据进行插值生成DEM,并采用数值精度指标、等值线、坡度和坡向值以及剖面值对不同算法插值结果进行分析和评价。实验结果表明,在地貌类型为丘陵和山地的混合地区,本文方法内插出的DEM效果相对较好,DEM具有良好的连续性,能够较好地模拟出研究区的真实地形。

The surface moving fitting(SMF)method has been widely used in DEM interpolation.However,the weight in traditional surface moving fitting algorithms is only determined by the distances between scattered points and insertion points,and the influences of DEM interpolation accuracy on the direction and distribution of scattered points are neglected.The Shepard weighted model is introduced into the surface moving fitting method to define weights in different intervals,the direction and distribution of scattered points are constrained,and an improved interpolation method for surface moving fitting is proposed in this paper.Yuhu hill in Hunan City University is taken as the study area which includes hilly region and mountain land.Linear,natural neighbor interpolation(NNI),surface moving fitting and the improved method are used to generate DEM based on scattered data,and spatial interpolation results and accuracies of four interpolation algorithms are analyzed and evaluated by using numerical prccilion index,contour,slope and aspect values,and profile values.The experimental results show that DEM interpolated by the improved interpolation method is much more precise than those of the other three interpolation algorithms in hill and mountain regions,and the contours derived from it has good continuity which can accurately reflect the real terrain better.