On 22/02/2008, Dylan Beaudette <[EMAIL PROTECTED]> wrote: > > If you have really big shapes that are spanning multiple UTM zones, then > setting up some kind of pre-processing logic which determines 1 of several > possible albers equal area conic projections might work. For example, if > the > coordinates are near the continental US, use one set of standard parallels > / > central lon/lat to setup the projection. Adjust these parameters > accordingly > for different (continents?) regions of the world. You should be able to > either find some existing EPSG codes which are close enough, or just make > up > your own, and define your projections in PROJ format. Then add them to the > spatial_ref_sys table.
If your results don't need to be super-accurate, you could make the simplifying assumption that the earth is spherical and calculate the area accordingly - via something like http://tinyurl.com/2uhedb Depends on what you're using it for. Rob :)
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