Interpolation & Surfaces
A continuous surface from scattered samples, with its support attached.
Interpolation produces a value for every cell, including the cells a kilometre from the nearest observation, and the output gives no hint which is which. These guides cover the methods — IDW, kriging, TIN and areal interpolation — but spend as much time on what they cannot tell you: why cross-validation is optimistic where the samples are dense, why kriging variance is a map of sample geometry rather than of error, why a finer cell size buys nothing, and how to ship a distance-to-nearest-sample raster so the reader can see where the surface is measurement and where it is arithmetic.
The variogram guide in the middle is the hinge. Before it, interpolation is a choice of formula; after it, it is a statement about how far a measurement reaches, which is what lets kriging report a variance and what makes the cross-validation at the end mean something.
Start here
The cornerstone guide — the whole workflow end to end. Everything after it goes deeper into one part of it.
Step 1 Spatial Interpolation Explained: Guessing Between the Samples spatial interpolation explained Begin the path →The full path, in order
The concepts underneath the work, then each task, then the errors that task produces. Work down, or jump to the step you need.
- Sample Design Explained: Where to Measure sample design explained 🧭 Concept
- How to Interpolate Points to a Grid with IDW in Python idw interpolation python ⚙️ How-To
- My IDW Surface Is Full of Bullseyes idw bullseyes 🔧 Fix
- The Variogram Explained: How Far Does a Measurement Reach variogram explained 🧭 Concept
- How to Fit a Variogram and Krige a Surface in Python kriging python ⚙️ How-To
- My Kriging Fit Fails or Returns a Flat Surface kriging fit fails flat surface 🔧 Fix
- How to Build a TIN and Interpolate Elevations tin interpolation python ⚙️ How-To
- IDW, Kriging, Splines or TIN? Choosing an Interpolator choosing an interpolator explained 🧭 Concept
- How to Cross-Validate an Interpolated Surface cross validate interpolation python ⚙️ How-To
- How to Choose a Cell Size for an Interpolated Surface choose cell size interpolation ⚙️ How-To
- My Interpolated Surface Extends Far Beyond the Data interpolation extends beyond data 🔧 Fix
- How to Interpolate to Polygons Instead of a Grid areal interpolation python ⚙️ How-To
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