[OSM-dev] Kosmos != Mapnik, Osmarender - projection problem

[Igor Brejc]

Dirk-Lüder Kreie wrote:
> What do you use to calculate the maxX (trivial) and maxY coordinates 
> for the tiles?
> There might be a hidden rounding error.
>
> All projection code used for tiles at home is in svn:
> http://svn.openstreetmap.org/applications/rendering/tilesAtHome/lib/tahproject.pm 
>
>
Dirk-Lüder, I owe you a beer ;). The culprit was "85.0511" constant 
which I (re)used a while ago from one of these perl scripts (it still 
says "#atan(sinh(pi)) = 85.0511 deg"). Unfortunately this is only an 
approximation, the actual difference (in radians) is 1.4844222297453324 
compared to 1.4844217274429494 - enough to make a difference on high 
zooms. Results: http://flickr.com/photos/28786233@N03/3022095011/

Thanks again

Igor

-- 
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