I've written a polygon-partition algorithm that works fairly well on 'polygon_with_islands'. I deal with the island-points by linking them to the perimeter of the polygon by a double-line thus turning the setup into one messy polygon. I would like to conform
to a strict & known standard (if there is any) when storing the messy polygon. The most obvious standard would be to store perimeter and islands separately. My algorithm is capable of ingesting the full mess, so I just write it all out .. but I doubt that
this is used by anyone else than me.