[postgis-users] Strange ST_Area problem

[Mike Toews]

On 25 March 2012 12:19, Eric Ladner <eric.ladner at gmail.com> wrote:
> Would EPSG:32230 be appropriate?  (WGS 72, UTM
> zone 30N)  I'm dealing with things roughly in the 30.0 to 31.0N range.

EPSG:32630 is a better projected reference, since it shares the same
spheroid, WGS 84, as EPSG:4326 (rather than mixing in the older WGS
72).
http://spatialreference.org/ref/epsg/32630/

You should also check out converting your geometry types into
geography types, which automagically calculates ST_Area (and
ST_Length, and others) using tangible units of metres.

http://postgis.refractions.net/docs/ch04.html#PostGIS_Geography

-Mike