I am looking for a method from Grass, GEOS, or similar that will delete those points in a geometry which do not affect its shape.
+----+----+ p0 p1 p2
p1 can be deleted without affecting the shape of the line
p0 p1 +----+ | \ p4 + \ | \ p3 +--------+ p2
p4 can be deleted without affecting the shape of the polygon
I am sure this has been asked/answered and there is probably a name for the output point set (akin to convex hull) but I am not sure what to search for.
It would be relatively straightforward (no pun intended) to write my own function but obviously silly if there is something out there already.