The Natural Neighbors Of Dem Interpolation And Fitting Method

Digital elevation model can be described to simulate the terrain surface by the limited number of terrain elevation. The terrain surface can be expressed by a group of sampling points. If you need elevation value of another location on the digital surface, interpolation and fitting methods can be used for processing this problem. In recent years, there are a lot of research for DEM interpolation and fitting methods and a variety of GIS spatial data interpolation and fitting methods. The key of interpolation and fitting is about the selection of the reference points. But each interpolation method has their own shortcomings and the disadvantages can be summarized as follows:(1). the interpolation precision can be affected by ill-distribution or too litter of the reference points; (2). Computational efficiency can be decreased by too many reference points. Therefore, it is necessary to find a balance between the selection of the reference points and the computational efficiency and put forward a new method of interpolation method.DEM based on triangulated irregular network can be better expressed the terrain feature and there has litter information redundancy. Aiming at the problem of linear interpolation based on TIN of DEM that local part is substituted by plane, the whole surface is not smooth and there is great difference in the practical terrain, this paper puts forward a new surface interpolation and fitting model based on natural neighbor. The main idea is that Delaunay triangulation of sample points is firstly established. Then the interpolation point is inserted and Delaunay triangulation is rebuilt. The first-order neighboring of the insertion point is considered as the reference points of interpolation. This method is that the known reference points can be well-distributed around the inserting point. The interpolation model is based on the effective dynamic subdivision of convex hull area of the set of the triangle influenced as the weight. The first-order and second-order neighboring of the insertion point is considered as the reference points of interpolation.The experiment shows that our method has more effective in structure and precision.In order to better visualize the expression of the DEM terrain, this paper exchange the result of the interpolation model to the format of Virtuozo-DEM---the national standard geospatial data. The format of Virtuozo-DEM can be converted to raster data in ArcGIS and this raster data in ArcGIS can be converted to any format for its supports, which can be expressed by different forms to express the DEM.Finally, this paper put forward the further research to the model of interpolation.