[OSM-dev] Mapnik: Data format in world_boundaries.tar.bz2 ?

[Martijn van Oosterhout]

On Nov 29, 2007 2:49 PM, Hakan Tandogan <hakan at gurkensalat.com> wrote:
> Ah, o.k., there is a .prj next to it...

What I think is relevent is:

>  "Mercator",
>  DATUM["D_WGS_1984",
>  PROJECTION["Mercator"],

This would correspond to +proj=merc +datum=WGS84

> >> Point Point(X=-19948430.3286263,Y=11572187.9256366)
>
> Any idea or pointers how I can transform those points into lat/lon
> coordinates? A perl library would be perfect ;-)

Ideally you'd want to use the proj4 library, but if you can live with
an external program cs2cs will do it:

cs2cs +proj=merc +datum=WGS84 +to +proj=longlat

Or find some other tools (someone mentioned gdal).

Hope this helps,
-- 
Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/