Greetings, I've searched the list archives, but didn't spot this question, so here goes.
I'm developing a client that uses OpenStreetMap tiles and overlays coordinate (lat/lon) information above it. It's custom C coded, so I can't use any of the libraries out there. I understand the discussion on the following URL about the tile names and the long2tilex, lat2tiley, tilex2long, and tiley2lat functions. http://wiki.openstreetmap.org/index.php/Slippy_map_tilenames However, at zoom levels less than 4 (or so), I get a worsening offset to the north and south of the equator as I map objects onto the maps. You can see this effect at the following URL: http://tinyurl.com/OSMLowZoom or http://ldeffenb.dnsalias.net.nyud.net/OSM/LowZoom.htm I'm using the floating-point X/Y value scaled by 256x256 to position the X/Y within a single tile. This works fabulously for the higher zooms, but, as you can see, completely misses the continental land masses for the lower zooms. Is there a different/better set of equations to use at lower zooms? Or is the project just that strange? Lynn (D) - Author of APRSISCE for Windows Mobile - An Amateur Radio tool _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
