[postgis-users] Polygon area in meters
kemal at cins.co.uk
Tue Feb 9 06:06:54 PST 2010
Thank you vincent,
I suspected there would be a solution in 1.5 but I'm trying to avoid doing
an upgrade since my pl/pgsql scripts always seem to break every time I do
(granted because of bugs/wrong assumptions in my code).
I will see if there I can get away with some projection, but I'ill probably
do the upgrade in the end since I generally prefer "clean" solutions.
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Picavet
Sent: 09 February 2010 15:54
To: PostGIS Users Discussion
Subject: Re: [postgis-users] Polygon area in meters
> part de Kemal Bayram
> Envoyé : mardi 9 février 2010 14:40
> I'm current working with data in long/lat (wgs84) format and using
> st_distance_spheroid to calculate the length of my linestrings in
> meters. I now need to calculate the area of my polygons and am
> wondering what the easiest way of doing this would be?
You should really consider upgrade to the new PostGIS 1.5 and use the
geography datatype, which supports st_area natively. Some other functions
are supported as well using the very behaviour you propose.
Please see :
> I am thinking projecting the polygon with an equal area projection and
> then using st_area on the result. Anyone have any ideas on suitable
There is a _ST_BestSRID(Geography) but I think it is more for intern use by
other functions «magically» operating on geography type.
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