spherical polygon
On Monday 08 February 2010, Karl Ove Hufthammer wrote:
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 km?? Any known conversion factors for the equal-area projections available in 'spTransform'?
Most equal area map projections use meter as the linear unit of measure. Cheers, Dylan
Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341