Spatial Interpolation

Spatial interpolation is the procedure of estimating the value of properties at unsampled sites within the area covered by existing observations. In almost all cases the property must be interval or ratio scaled. It can be thought of as the reverse of the process used to select the few points from a DEM which accurately represent the surface. The rationale behind spatial interpolation is the observation that points close together in space are more likely to have similar values than points far apart (Tobler's Law of Geography). Spatial interpolation is a very important feature of many GISs. Spatial interpolation may be used in GISs: 1)To provide contours for displaying data graphically, 2)To calculate some property of the surface at a given point, 3)To change the unit of comparison when using different data structures in different layers, 4)As an aid in the spatial decision making process both in physical & human geography, as well as interrelated disciplines such as mineral prospecting & hydrocarbon exploration. Many of the techniques of spatial interpolation are twodimensional developments of one dimensional methods originally developed for time series analysis