[OSM-dev] Coordinate to Pixel at lowzoom

[OJ W]

Do the conversion at 8 zoom levels higher than your tile (i.e. the
tile which that pixel represents)

i.e. if someone clicks the top-left pixel of 1,1 at z1 then do tile2ll of
256,256 at z8.  If they click the 3rd pixel across from that then do
tile2ll of 256+3,256 at z8.

(replace 8 by log2 of your tile width, if you're not using 256x256)


On Thu, Oct 8, 2009 at 2:36 AM, Lynn W. Deffenbaugh (Mr)
<ldeffenb at homeside.to> wrote:
> 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.