Hi, (Management overview: New or/p in SVN. Check it out.)
Frederik Ramm wrote: > I'm currently looking into this whole caption tile generation > stuff... but is it possible that nobody ever tried lowzoom with the > current client? Ok, I took the following tile as a test case: http://a.tah.openstreetmap.org/Tiles/tile/10/534/345.png It is obviously broken as it is now, Mapnik hast the label positions right: http://c.tile.openstreetmap.org/10/534/345.png So, after fixing Tileset.pm to allow the creation of caption tiles (not commited as it was an ugly hack - someone do it right please), I first tried perl tilesGen.pl xy 534 345 10 which created a correct label tile. Then I did the corresponding perl tilesGen.pl xy 33 21 6 and this created, among others, the same tile, just wrong by about 10 kilometres. A quick calculation shows us that the "Osmarender error" (resulting from choosing 1/cos(middle latitude) of a tile for projecting all of it instead of applying this formula to every latitude) would be in the range of up to +/- 6% for a Z6 tile in the 50°N area, yielding an error of up to 15km - that roughly matches what we're seeing above. The error gets larger in a super-linear fashion if you look at smaller zoom levels (higher percentage of a higher value), although I cannot quite imagine it becoming so big that Rome would be placed in Finland (or "hell freezes over" as some would have it!). I would actually like to modify orp.pl to use the Proj.4 library, then it could support any projection you want. But for the mean time I have applied a patch that was sent to me by Alfons Andorfer a long time ago which makes orp.pl use a correct Mercator projection. (It took me about 20 attempts to get valid data from OsmXAPI today, all the other attempts were simply cut off somewhere in the middle... at a different point every time.) It seems to work now. This is the level 10 caption tile generated now: http://www.remote.org/frederik/tmp/test1.png and this is what it was before the or/p fix: http://www.remote.org/frederik/tmp/test2.png Committed or/p fix. I'm too lazy now to render a normal Z12 tile with old and new methods and compare whether they still look the same - if someone else wants to do that... Bye Frederik -- Frederik Ramm ## eMail [EMAIL PROTECTED] ## N49°00'09" E008°23'33" _______________________________________________ Tilesathome mailing list [email protected] http://lists.openstreetmap.org/listinfo/tilesathome
