Hi, On 05/20/11 14:09, Dirk-Lüder Kreie wrote:
You write there that the cutting is done sequentially from large to small. Seeing as how the polygon complexity is one major factor in the cutting process, wouldn't it make sense to use more smaller, more precise polygons to cut out the small stuff first with "better" polygons and then assembling the larger parts from that?
Not with the current Osmosis implementation. If you had, say, 150 "precise" country polygons and were to cut them out of a 1.2 billion node planet file, then that would mean Osmosis does 180 billion point-in-precise-polygon tests, and that would take quite a while. The top-down approach I am using means fewer tests.
Better algorithms for tiling a surface exist but haven't yet been put to use in Osmosis. Very fast tile splitters exist in the mkgmap and routing preprocessing arenas but they only do rectangles and don't do --complete-ways which I am increasingly using.
Bye Frederik _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
