[postgis-users] GeomUnion function

[Paul Ramsey]

 From CVS,

multi(geometry)

P.

On Tuesday, May 18, 2004, at 07:24 AM, Hubert Fröhlich wrote:

> Hi list,
>
> I am working with Postgis 0.8.1 and GEOS 1.0.0, PostgreSQL 7.4.1 .
>
> I want to use the GeomUnion(geometry1, geometry2) function.
>
> When I apply GeomUnion on two arbitrary MULTIpolygons, I receive  
> MULTIPOLYGONS or POLYGONS, depending on the relationship between the  
> two geometries.
>
> However, when I want to insert the result into a table, I have to  
> decide upon using only one geometry type.
>
> If the result is a MULTIPOLYGON and I insert a to a table with  
> MULTIPOLYGONS, everything is fine.
> If the result is a POLYGON and I insert a to a table with  
> MULTIPOLYGONS,
> I get a constraint violation like
>
> ERROR:  new row for relation "lkrx" violates check constraint "$2"
>
> What I need is a function converting Polygons into Multipolygons or a  
> GeomUnion function forcing MULTI... results.
>
> How can I do that?
>
> Regards,
>
> Hubert
>
>
>
>
>
> --  
> ----------------------------------------------------------------------- 
> --------
> Dr.-Ing. Hubert Fröhlich			
> Bezirksfinanzdirektion München 			
> Alexandrastr. 3, D-80538 München, GERMANY
> Tel. :+49 (0)89 / 2190 - 2980
> Fax  :+49 (0)89 / 2190 - 2997
> hubert dot froehlich at bvv dot bayern dot de
>
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>
      Paul Ramsey
      Refractions Research
      Email: pramsey at refractions.net
      Phone: (250) 885-0632