[Openstreetmap] Converting x,y to latitude,longitude and back

nick at hogweed.org nick at hogweed.org
Tue Jan 31 23:56:17 GMT 2006


Hello everyone,

As part of the new version of Freemap using the slippy map I would like to get 
hold of some code which converts between x,y pixel coordinates and lat/long 
and vice/versa, where the map is defined by bottom left lat,long, scale and 
pixel width/height.

Does anyone know any good open source code that will do that? Any language 
will do, I will convert it to JavaScript. Tried to fathom out what was going 
on in the slippy map code but it's hard to locate any code which does the 
conversion.

A related point - what scales (in pixels per lat/lon unit) do the zoom levels 
in the slippy map translate to?

Thanks,
Nick




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