Hi Ticker, Gerd Petermann wrote > Alternative would be to implement a clipper which doesn't need > area.intersect(). I've once coded the "Sutherland-Hodgman algorithm" but > didn't use it yet as it failed with special cases like self-intersecting > ways or concave shapes producing spikes, but I still think this would be a > great improvement. See attached (out-aged) patch and the wiki > https://en.wikipedia.org/wiki/Sutherland%E2%80%93Hodgman_algorithm > for further details.
I just noticed that the algo is already used in ShapeSplitter.clipSinglePathWithSutherlandHodgman(), the comment says "Clip a single path with a given rectangle using the Sutherland-Hodgman algorithm. This is much faster compared to the area.intersect method, but may create dangling edges." I think these danling edges are now removed in the RemoveObsoletePointsFilter, so maybe it is worth trying. Gerd -- View this message in context: http://gis.19327.n8.nabble.com/patch-to-write-polygons-in-decreasing-order-tp5884038p5885439.html Sent from the Mkgmap Development mailing list archive at Nabble.com. _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev