[postgis-users] Merge rectangles

[Paragon Corporation]

You don't need to do array unless you have a reason for that LIMIT.  

ST_Union is an overloaded function: One version is an aggregate and one
takes an array of geometries.

So below is a bit shorter to write:

SELECT ST_Union(poly)
FROM portal.catalog
WHERE cat.type = 'CADRG';




-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of DrYSG
Sent: Wednesday, August 15, 2012 2:39 PM
To: postgis-users at postgis.refractions.net
Subject: [postgis-users] Merge rectangles

In the table portal.catalog 

column poly is a geometry (always a rectangle, with datum EPSG 4326) column
type is a text field.

I want to find all the records who have a type of "CADRG" and merge the
polygons into the simplest shape that covers all the items in the array
(I.e. if they form a square with a hole, then I want that, if it has to be a
multipolygon, so be it).

Is this the correct way to do that?


SELECT ST_AsText(ST_Union(
ARRAY(
	SELECT poly 
	FROM portal.catalog as cat
	WHERE cat.type='CADRG'
	LIMIT 10
	)
	)
)



--
View this message in context:
http://postgis.17.n6.nabble.com/Merge-rectangles-tp4999357.html
Sent from the PostGIS - User mailing list archive at Nabble.com.
_______________________________________________
postgis-users mailing list
postgis-users at postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-users