[postgis-users] union operation

[lighthousej at gmail.com]

Thanks for the replies.

Here's my version info:
postgis_full_version
-------------------------------------------------------------------------------------
POSTGIS="1.3.5" GEOS="3.0.3-CAPI-1.4.2" PROJ="Rel. 4.6.1, 21 August 2008"  
USE_STATS

I see the version of GEOS is lower than the 3.1.1 that you recommend. I  
thought at one point I was using that 3.1.1 version.
I did read up on the new union algorithm and how it speeds up the process,  
but if upgrading fixes this too, I'm up for using it.
I just tried to install Pg 8.4.0 via linux installer, but I didn't see any  
PostGIS package in stackbuilder?
I can test it's capability by compiling it on my box, but it has to be in  
stackbuilder before I can use it.

The geometries themselves look okay, they specify polygons that have some  
area.
I don't have any handy at the moment, but I will run them through the  
isvalid() function and take your .sql file into consideration.


Any more things to look at would be much appreciated.

Thanks,
Nate

On Aug 7, 2009 3:14am, "Suhr, Ralf" <Ralf.Suhr at itc-halle.de> wrote:
> Your have some invalid geometries.



> Use

> update table set geom = cleangeometry(geom) where isvalid(geom) = FALSE;



> The SQL-Function can be found at

> http://www.sogis1.so.ch/sogis/dl/postgis/cleanGeometry.sql



> Gr Ralf



> -----Ursprüngliche Nachricht-----

> Von: postgis-users-bounces at postgis.refractions.net  
> [mailto:postgis-users-bounces at postgis.refractions.net] Im Auftrag von  
> Nathan Widmyer

> Gesendet: Freitag, 7. August 2009 00:41

> An: PostGIS Users Discussion

> Betreff: [postgis-users] union operation





> I have many polygons I'm trying to make a union of. The polygons have a  
> high possibility of shared vertices which causes the "NOTICE:

> TopologyException: found non-noded intersection between ..." error.



> How can I avoid this error?



> I did find a reasonable query that used linework which solved that  
> problem, but was problematic in other ways I think (I forgot those other  
> circumstances). _______________________________________________

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