AW: [postgis-users] Geomunion

[Andreas Laggner]

Hi Thorsten,
do you want to perform a dissolve (you put geometries from many rows in 
one row) or what do want to achieve?
with geomunion you can do very different things!!!!
cheers      Andreas

Thorsten Kraus schrieb:
> 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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>
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-- 
Dipl. Geoökologe Andreas Laggner
Institut für Ländliche Räume (LR)
Bundesforschungsanstalt für Landwirtschaft (FAL)

Institute of Rural Studies
Federal Agricultural Research Centre (FAL)

Bundesallee 50
D-38116 Braunschweig

Tel.: (+49) (0)531 596 5515
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