[OSM-talk] North Pole

[Patrick Weber]

The issue is not so much with the OSM data, which can infact deal with 
the North (and South) Pole, but with the projection used for the display 
of the data. The Mapnik Layer, along with all other common Ajax style 
slippy maps (Google, VE, Yahoo ....) rely on the Mercator projection. 
The Mercator projection has many positive features which makes it 
suitable for a slippy map, but one major drawback is that a Mercator map 
can never fully show the polar areas, since linear scale becomes 
infinitely high at the poles. the other significant drawback is that 
areas are not preserved, and scale is only ever valid for one specific 
place.

See http://en.wikipedia.org/wiki/Mercator_projection

Heiko Jacobs wrote:
> Peter Childs schrieb:
> We just had this discussion at talk-de some days before...
> There is an North Pole at lat=90 lon=9 in OSM data.
> I assumed, that data outside lat=-85...85 (and lon=-180---180)
> is put at 0 instead of x? Does anyone knows more precise,
> how API and renderers handle this dort of elements?
>
> Mueck
>
>
> _______________________________________________
> talk mailing list
> talk at openstreetmap.org
> http://lists.openstreetmap.org/listinfo/talk
>   
-------------- next part --------------
A non-text attachment was scrubbed...
Name: p_weber.vcf
Type: text/x-vcard
Size: 354 bytes
Desc: not available
URL: <http://lists.openstreetmap.org/pipermail/talk/attachments/20090619/d70951ba/attachment.vcf>