[R-sig-Geo] spherical polygon

[Karl Ove Hufthammer]

On Sun, 7 Feb 2010 17:30:23 -0800 Dylan Beaudette 
<dylan.beaudette at gmail.com> wrote:
> How about an equal-area map projection?
> 
> http://en.wikipedia.org/wiki/Map_projection#Equal-area

Good idea. This will easily give you correct relative area measures, 
which will often be sufficient.

But how to convert these into absolute measures, for example, the area 
in km²? Any known conversion factors for the equal-area projections 
available in 'spTransform'?

-- 
Karl Ove Hufthammer