[postgis-users] Problem with slow GeomUnion (geom, geom)

[Mark Cave-Ayland]

On Fri, 2007-06-01 at 12:00 +0200, Matt Doughty wrote:
> Hi Mark,
> 
> I'm trying to do a geometric union (I'm more used to doing these things
> in ArcGIS where it'd be a union: A topological overlay of two or more
> polygon spatial datasets that preserves the features that fall within
> the spatial extent of either input dataset; that is, all features from
> both datasets are retained and extracted into a new polygon dataset
> (ESRI website))
> 
> In this case I'm not bothered about what happens to attributes, it's the
> polygons that I want.
> 
> The input tables are as follows:
> 
> 	1. Table1
> 		name character varying(70),
>   		the_geom geometry
> 	2. Table 2
> 		name character varying(70),
>   		the_geom geometry
> Cheers,
> 
> Matt

Okay, this is getting a little out of my comfort zone so someone else
may need to help out here - is basically what you want to return all the
polygons that overlap each other from your two tables?


Kind regards,

Mark.

-- 
ILande - Open Source Consultancy
http://www.ilande.co.uk