Quadtree, ray shooting and approximate minimum weight Steiner triangulation

We present a quadtree-based decomposition of the interior of a polygon with holes. The complete decomposition yields a constant factor approximation of the minimum weight Steiner triangulation (MWST) of the polygon. We show that this approximate MWST supports ray shooting queries in the query-sensitive sense as deened by Mitchell, Mount and Suri. A proper truncation of our quadtree-based decomposition yields another constant factor approximation of the MWST. For a polygon with n vertices, the complexity of this approximate MWST is O(n logn) and it can be constructed in O(n log n) time. The running time is optimal in the algebraic decision tree model.