Interpolating data

Spatial interpolation is the process of estimating an unknown value between two known values taking into account Tobler's First Law:

"Everything is related to everything else, but near things are more related than distant things."

This recipe does not undertake to teach you the advanced concept of interpolation because it is too complex for this book. Instead, this recipe will guide you to create a terrain surface using the following:

• A feature class with sample elevation points

• Two interpolation methods: Inverse Distance Weighted (IDW) and Spline

Note

For further research, please refer to: Geographic Information Analysis, David O'Sullivan and David Unwin, John Wiley & Sons, Inc., 2003, specifically the 8.3 Spatial interpolation recipe of Chapter 8, Describing and Analyzing Fields, pp.220-234.

Getting ready

In this recipe, you will create a terrain surface stored as a raster using the PointElevation sample points. Your sample data has the following characteristics:

• The average...