Coordinate System – Simplifying Geometries (Generalization) for Efficient Data Handling

coordinate systemgeneralizationsimplify

What are the recommended ways of simplifying geometries? Keeping in mind projections, and simplifying state geometries for example.

I've heard about converting to an 'equi-distant' projection that allows simplification without distortion, and then converting back to your chosen projection.

Best Answer

As glennon mentioned, the standard algorithm for doing this is Douglas-Peucker, which is the default algorithm used in software such as PostGIS (i.e. GEOS) via St_Simplify, ArcGIS via Generalize and GRASS via v.generalize. The Wikipedia article also links to a Python implementation.

GRASS supports a number of different algorithms, as explained in the help page for v.generalize.

On the projection issue, I think in this case its a red herring which can be ignored. The only issue which comes to mind is potentially densifying lines to prevent them from being oversimplified.

Related Question