Lab 8 – Surface Interpolation

An output from raster calculator determining the difference between
two output interpolation rasters using the same input points values

This week's lab involved using various interpolation techniques, generating surfaces, and learning limitations of each technique.  Each interpolation process determines the values of unknown cells based on their spatial relationship to known nearby values.  The difference between them is, generally, the weight given to each of the known values - which is usually based on distance and spatial trends.  At right is a comparison of two common interpolation methods: Inverse Distance Weighted interpolation and Spline interpolation.  The most obvious incongruities occurred in areas of low sample density, suggesting these two interpolation techniques duffer in predictions when sample density is low.