A demonstration of how to calculate the areas of Voronoi regions clipped by geographic features using D3.
[D3’s implementation](Sutherland–Hodgman algorithm) of the Sutherland–Hodgman algorithm only works for convex clip polygons, but we exploit the fact that Voronoi regions are guaranteed to be convex, and use each Voronoi region as a clip polygon, with the projected geographic boundary as a subject polygon.
In response to a question by Gonzalo Bellver.