[postgis-users] Region-style representations

[Paul Ramsey]

In the CVS version, you already can:

select collect(the_geom) from geotable group by someattr;

returns aggregate features (geometrycollection) grouped by an attribute.

P.

On Monday 22 April 2002 03:09 pm, you wrote:
> Your definition sounds good enough to me.
> The reason this came up is that I'm discussing using postgis with some
> other applications which traditionally have created regions in arcinfo for
> their analysis.  Is it possible (or going to be possible) to create
> multipolygons from polygons within postgis, via some dissolving on an
> attribute(s) function?
>
> Tyler
>
>
>
>                       Frank Warmerdam
>                       <warmerdam at pobox.com>                   To:      
> postgis-users at postgis.refractions.net Sent by:                             
>   cc:
>                       postgis-users-admin at postgis.refr        Fax to:
>                       actions.net                             Subject:  Re:
> [postgis-users] Region-style representations
>
>                       04/22/2002 11:21 AM
>                       Please respond to postgis-users
>
> Tyler Mitchell wrote:
> > Hi guys,
> > Are there plans/possibilities of representing polygons a la ArcInfo
> > region-style?  Is this covered off in another OGC spec?
>
> Tyler,
>
> My understanding is that regions in arc/info are a way of making a feature
> (with attributes) that consists of one or more simple polygons that may
> have
> wholes.  That is region is potentially a set of disconnected areas.  In
> OGC Simple Features this would be a MultiPolygon geometry and should be
> supported directly by PostGIS.
>
> I am not absolutely certain if my OGR region handling actually treats
> regions properly as MultiPolygons or not, but if so I would imagine they
> could be loaded into PostGIS with ogr2ogr.
>
> Best regards,