[postgis-users] Computing area in km^2 from 4326 geometries

[Craig Miller]

ROFL.. I just gave the conversion to acres. and I gave it wrong.  Pls ignore
this post.

 

--Craig

 

 

  _____  

From: Craig Miller [mailto:craig.miller at spatialminds.com] 
Sent: Tuesday, September 28, 2004 3:07 PM
To: 'PostGIS Users Discussion'
Subject: RE: [postgis-users] Computing area in km^2 from 4326 geometries

 

If the area function is returning square meters (depends on your projection)
then just divide the answer by 4046.896 to get kilometers.

 

All area functions are squared by definition.

 

--Craig

 

 

 

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From: Ethan Alpert [mailto:ealpert at digitalglobe.com] 
Sent: Tuesday, September 28, 2004 2:57 PM
To: PostGIS Users Discussion
Subject: [postgis-users] Computing area in km^2 from 4326 geometries

 

How does one compute areas in km^2? I was thinking something like
area2d(transform(the_geom,<someEPSG>)). 

How do others do this?

 

Thanks!

 

-e

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