[postgis-users] query question

[G. van Es]

Thanks Maxime,

That worked!  

However now I see another problem. 

Some polygons are touching in a way they shouldn't. This is a problem of our drawing department but since there are a few thousand of those objects it would be nice to query with a certain tolerance. Say, the object should overlap for at least 80%. 

Well, that is too much rocket science for me at the moment.
If someone has any clue if this is possible please drop me a line.

Thanks,
Ge

--- On Wed, 11/4/09, Maxime van Noppen <maxime at altribe.org> wrote:

> From: Maxime van Noppen <maxime at altribe.org>
> Subject: Re: [postgis-users] query question
> To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
> Date: Wednesday, November 4, 2009, 3:56 AM
> G. van Es wrote:
> > I want to have a list of wich geometry of a certain
> type is touching or crossing another type.
> > 
> > Can someone point me in the right direction?
> 
> Hi,
> 
> If I understand your problem you want to find for each
> geometry in your
> table which geometries intersect with it ?
> 
> This can be done with the ST_Intersects function and an
> self-join.
> Something like :
> 
> SELECT t1.type, t2.type FROM T t1, T t2 WHERE t1.type !=
> t2.type AND
> ST_Intersects(t1.the_geom, t2.the_geom);
> 
> This will generate an output like :
> 
> t1.type | t2.type
> -----------------
> 13      | 12
> 13      | 1
> 13      | 4
> 12      | 3
> 12      | 8
> ...
> 
> -- 
> Maxime
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