Spatial distribution of precipitation in China based on 3D TPS interpolation

Common spatial interpolation models usually only consider the geographical coordinates, but elevation values are not taken into account. Threedimensional thin plate spline model (3D TPS), in which the elevation values were treated as one of important independent variable factors, was applied in the research on the spatial interpolation of annual precipitation in China in this paper in order to improve the interpolation precision and reduce the error which was produced by the great elevation changes. The control of ArcGIS Engine was used as a secondary development tool based on Visual Basic.Net language. The elevation values were extracted from China digital elevation model (DEM). The geographical coordinates and annual precipitation values were extracted from spatial distribution map of meteorological stations. Then, the DEM map was used as a template and each grid point was interpolated with 3D TPS model so that the spatial distribution map of annual precipitation in China was produced. Finally, after the analysis and comparison of different interpolation models, it is concluded that the 3D TPS model has the highest interpolation precision (standard deviation is 113.95) and obvious advantages especially applied in the areas with great topographic relief.