AW: [postgis-users] Geomunion

[Thorsten Kraus]

OK, I found a solution:
SELECT multi(geomunion(geom)) from table1.
 
Now I want to use this query to get the number of holes in the union of all geometries:
SELECT NumInteriorRings(multi(geomunion(geom))) FROM table1
 
This queries perform very very bad. I cancelled a query on a table with about 10000 geometries because it takes over an hour without being completed. Is there a better way to union such a big number of geometries?
 
 -----Ursprüngliche Nachricht-----
Von: postgis-users-bounces at postgis.refractions.net [mailto:postgis-users-bounces at postgis.refractions.net]Im Auftrag von Thorsten Kraus
Gesendet: Donnerstag, 30. August 2007 12:54
An: PostGisMailingList (E-Mail)
Betreff: [postgis-users] Geomunion



Hello, 

I want to union all geometries of a table into one big geometry. Do you know how this task can be performed the best way?

Regards, 
Thorsten 

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