Effects of interpolation parameters in multi-log radial basis function on the interpolation accuracy of DEM

Interpolation algorithm is one of the most important factors which influence on the accuracy of DEM. After interpolation method is confirmed, interpolation parameters are a primary cause for the accuracy of DEM. However, there are few researches on how interpolation parameters influence interpolation algorithm as well as the interpolation accuracy at last. In this paper, the interpolation parameters in interpolation algorithm of multi-log radial basis function are chosen as the research objective, and it selects the data of 1: 50000 at discrete points of five different morphologies. It uses mean error metrics and researches the influence of smooth factor, search points and search direction on the interpolation accuracy of DEM. Finally, the experiment result shows that: 1) the bigger smooth factor is, the closer to original data DEM describes landforms. On the other hand, it leads to extremely larger mean error. For the interpolation algorithm of multi-log radial basis function, it is a good choice for smooth factor as a smaller number or zero; 2) the more the search points are in interpolation algorithm, the higher interpolation accuracy of DEM is. The best search points are 16 to 32 points; 3) due to the symmetry of radial basis function, search direction can also influence the interpolation accuracy of DEM. Generally speaking, four-directional search and eight-directional search are better than directionless search. Taking interpolation efficiency into consideration, four-directional search is the best choice; 4) the paper establishes a model of interpolation accuracy of DEM based on interpolation parameters according to the influence of smooth factor, search point on interpolation accuracy of DEM.