Jiri, thanks for your quick response! On Sun, Feb 07, 2010 at 11:09:09AM +0100, Jiri Klement wrote: > Multipolygon painting speed was improved in 2793, but Lake Inari was > very slow anyway, because it contains multiple outer polygons. I've > added optimalization for this case today (r2948). > > Btw. outer polygons are not used correctly in the lake, when there is > small lake inside of island on the big lake, the small lake shouldn't > be part of the big lake multipolygon.
I followed the example on the wiki page http://wiki.openstreetmap.org/wiki/Relation:multipolygon which does suggest that lakes within islands can be defined as role=outer: --- start quote --- >From the possibility of having multiple outer rings in one relation, it also >follows that you can easily model "islands" within a hole: <relation id="1"> <tag k="type" v="multipolygon" /> <member type="way" id="1" role="outer" /> <member type="way" id="2" role="inner" /> <member type="way" id="3" role="outer" /> </relation> A construct like this would previously have required different multipolygon relations, one with way 1 being outer and way 2 being inner, as well as one with way 2 being outer and way 3 being innner. Such cascading is still recommended when the "island" in the middle is something else than the area on the outside, but where the "island" is the same stuff it can just be made a hole in the hole. --- end quote --- Admittedly, the lakes within islands are not the same stuff as the outer lake (they should at least be called something else than the main lake). I will fix this soonish, also to give mkgmap's multipolygon code some further exercise. (Mkgmap must split multipolygons to normal polygons for Garmin.) Another problem that I had with multipolygons was defining one for Kemijärvi today (http://www.openstreetmap.org/browse/changeset/3812690, http://www.openstreetmap.org/browse/relation/403320). JOSM complained about intersecting lines, not saying which lines, but I could not see anything special on the screen, except some almost-self-intersecting outer coastline. Based on the node count given (5008 IIRC), I guessed that it would be the outer coastline that JOSM is complaining about. The outer coastline would consist of 9*500+508 nodes. One last thing: Is there an easy way to download a way, node or relation by the browse URL? I have clicked in the web browser to a random node and copied the coordinate URL to JOSM. I wish there were a simpler method. Also, would it be possible to download select relation members in the relation browser, say, if I only want to tweak the coastline but not the islands? There are many complex lakes in Finland. Marko _______________________________________________ josm-dev mailing list josm-dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/josm-dev
