The Spatial Interpolations in GIS

Spatial interpolation is the procedure of estimating the value of properties at unsampled sites within the area covered by existing observations. In a broad sense, spatial interpolation includes point interpolation and areal interpolation. Several spatial interpolation methods were discussed in this paper including the base theory and the arithmetic of the methods. There is no absolutely optimal spatial interpolation method. There is only relatively optimal method in special situation. Hence, the best spatial interpolation method should be selected in according with the qualitative analysis of the data, exploratory spatial data analysis and repeated experiments. In addition, the result of spatial interpolation should be strictly examined for its validity. How to adapt the basic interpolation methods and create some new methods for special purpose to applied in different studies is the most important thing should be done in the spatial interpolation.