FINDPOLY: A fast points-in-polygons test

A fast INPOLYGON for multiple polygons.

Given a collection of polygons and a set of query points, FINDPOLY determines the set of enclosing polygons for each point. Arbitrary collections of polygons and query points are supported, and general non-convex and multiply-connected inputs can be handled. FINDPOLY employs various spatial indexing + sorting techniques, and is reasonably fast for large problems.

See POLYDEMO to get started with an example problem.