[postgis-users] GeomUnion problem

[Brent Wood]

--- Paul Ramsey <pramsey at refractions.net> wrote:

Hi Paul,

Much appreciated.

I never received Martin's first reply describing the buffer approach. I've
checked my trash folder & I did not delete it by mistake, I did recieve what
now appears to be his second message mentioning the version as a possible
issue, which was the one I replied to.

Thanks for all the info. I'll have a go with the buffer approach & see if that
works, if not I'll try v3.0.

I appreciate that v3 should work seamlessly, but I'm well down the track with a
very effective system so far & if I can make v2 do the job, then it ain't broke
enough yet :-)

The output is for reports to two Govt Depts, with about 2500 colour publication
quality maps. All work done in FOSS (postgis/GMT/R)

Many thanks for the help! As always, it is so much better than that for any
proprietary software I've ever seen!

 
Thanks again,

   Brent Wood

> On 3-May-07, at 6:36 PM, Brent Wood wrote:
> 
> > Is GEOS v3RC going to be reliable enough for a mission critical  
> > production job
> > with several million polygons to be manipulated?
> 
> Probably.
> 
> > What is entailed in upgrading GEOS?
> 
> ./configure ; make ; make install
> 
> > Do I need to rebuild & reinstall PostGIS?
> 
> No, you can drop the new GEOS in behind.  Re-connect to the database  
> and the new library will be loaded.
> 
> > Will the current DB/data still be accessible?
> 
> Yes.
> 
> > Or is there some way of tweaking the underlying polygons to be  
> > combined to
> > address the problem?
> 
> Martin gave that recipe:  buffer(geomunion(buffer(a,0.1),buffer(b, 
> 0.1)),-0.1)
> 
> P
> 
> >
> >
> > Appreciated,
> >
> >    Brent
> >
> >
> >>
> >> Brent Wood wrote:
> >>> Hi,
> >>>
> >>> I'm not sure what the problem is here, hopefully someone can help.
> >>>
> >>> I have some polygons cropped to cell boundaries. (select  
> >>> intersection...)
> >>> I want to generate the geomunion of these for each cell, which seems
> >>> straightforward, but GEOS is throwing an error...
> >>>
> >>>    select astext(geomunion(track_cell_geom)) from effort_cells3  
> >>> where
> >> cell_id =
> >>> 73721;
> >>> NOTICE:  TopologyException: no outgoing dirEdge found
> >>> (168.077,-40.1961,-40.1961)
> >>> ERROR:  GEOS union() threw an error!
> >>>
> >>>
> >>>
> >>> Can anyone say what this means & what I need to do to work around  
> >>> it?
> >>>
> >>> Thanks,
> >>>
> >>>   Brent Wood
> >>> _______________________________________________
> >>> postgis-users mailing list
> >>> postgis-users at postgis.refractions.net
> >>> http://postgis.refractions.net/mailman/listinfo/postgis-users
> >>>
> >>
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