On Jan 21, 2008 11:58 AM, 80n <[EMAIL PROTECTED]> wrote: > I've been working on a captions layer for low zoom levels (z4 - z7). > > The results are nice, but there seems to be a projection problem. Items are > being displaced vertically. > > Everything is spot-on for z8-z12, but when I try to repeat the process for > z4-z7 then the error is apparent. > > I'm guessing at the moment that the problem has always been there, but is > insignificant at z8, whereas at lower zoom levels it starts to become quite > noticeable.
Sounds a lot like: http://wiki.openstreetmap.org/index.php/Osmarender_bug The error grows by the square of the zoom, so at lower zoom levels it gets worse, much worse. > Is there anyone who is familiar with the mercator projection code in > tilesgen.pl / tahproject.pm that might be able to shed some light on this > problem? My guess is that the mercator preprocessor needs to be invoked to project each point individually, and not just the four corners with linear interpolation. Note: I think the new lowzoom process has similar issues: http://www.informationfreeway.org/?lat=-33.92&lon=22.52&zoom=11&layers=B000F000F Have a nice day, -- Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/dev
