GEO 481 Lecture Notes - Lecture 8: Spline Interpolation, Inverse Distance Weighting, Multivariate Interpolation
2 Apr 2019
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The geographic distribution of sample points: sample points should be well distributed. Regular point samples (not ideal but not possible in most cases) The core idea behind spatial interpolation methods: tobler"s first law of geography: Everything is related to everything else, but nearby things are more related than distant things . Inferring the unknown value based on a pre-defined mathematical equation. Idea: closer points have more influence on the unknown value. Wi is the weight, zt is the value at a sample point; di is the distance from the sample point to the unknown distance. P is a power parameter which determines how distance can influence the weight. P=0, every point has the same weight. The larger the p, the smaller influence of farther sample points. Fixed radius: define a search distance and all points that fall into this search radius will be used.
