[OSM-dev] osmarender+tiles at home projection bug
Jochen Topf
jochen at remote.org
Thu Feb 15 10:19:24 GMT 2007
On Thu, Feb 15, 2007 at 12:02:12PM +0100, Andreas Brauchli wrote:
> > Osmarender
> > a) can't do proper trig and is using a simpler approximation to cos()
> > (this could be improved by adding more terms), and
> > b) because you can't do a function call, is using a constant
> > transformation across a whole render.
> might that be a solution:
>
> 1. create the svg untransformated (no cosine approximation)
> 2. postprocess the svg to correct the projection - a simple perl script
> could do that
>
> it creates the burden of chaining operations, especially if we're not
> rendering large areas where the correction isn't that obvious
It would be much easier to do it the other way round: Pre-process the
OSM file and add projected coordinates to it and then let Osmarender do
its thing. Its easier because you just have to look at all the @lat and
@lon attributes of the nodes while in SVG there are many places which
have coordinates.
Frederik has done some work on that. See
http://wiki.openstreetmap.org/index.php/Osmarender_bug .
Jochen
--
Jochen Topf jochen at remote.org http://www.remote.org/jochen/ +49-721-388298
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