Map bounds and exclusion areas may intersect

[Indy2222]

CDT algorithm is used for map triangulation. Constraint edges are inputted to the algorithm. It is required that there are no intersections among the constraint edges.

An offsetted exclusion area polygon might intersect the (shrunk) map boundary. Solve this by e.g. clipping the exclusion areas to the shrunk map boundary. Make sure that there won't be any issue with coincidental edges (clipped polygon & part of the map boundary).