PostGIS Performance: Simplification

PostGIS offers multiple geometry simplification functions to reduce vertex count and improve performance. ST_Simplify uses Douglas-Peuker algorithm for line simplification, while ST_SimplifyVW applies Visvalingam-Whyatt for better polygon shape preservation. ST_ReducePrecision snaps to a grid while maintaining validity, unlike ST_SnapToGrid which can create invalid geometries. For shared boundaries, ST_CoverageClean and ST_CoverageSimplify handle groups of polygons while preserving topology. Combining techniques like ST_ReducePrecision with ST_Simplify often yields optimal results.