[postgis-users] TopologyException with geomunion

[strk at refractions.net]

Can you provide the HEXWKB (canonical output)
of the geometries triggering the error 
if this happens with GEOS-2.1.4 ?
--strk;

On Wed, Nov 02, 2005 at 03:32:32PM +0000, David Orme wrote:
> Hi all,
> 
> I've run into an exception when trying to union two multipolygons.  
> The features are both simple and valid:
> 
> range_maps=# select isvalid(geom), issimple(geom) from viverrid_psar  
> where node_number in (-3,-21);
> isvalid | issimple
> ---------+----------
> t       | t
> t       | t
> (2 rows)
> 
> 
> but when I try and union these I get the following:
> 
> range_maps=# insert into viverrid_psar (taxon_name, node_number,  
> subclades, branch_length,  n_tips, n_subclades, node_height,  
> richness, geom)values ('',-2,'{-3,-21}',9.9,31,2,18.1,31,(select  
> geomunion(geom) from viverrid_PSAR where node_number in (-3,-21)));
> NOTICE:  TopologyException: Directed Edge visited twice during ring- 
> building at  (1.13203e+07,402571)
> ERROR:  GEOS union() threw an error!
> 
> I don't think I'm doing something dumb, but I thought I'd check  
> before I start posting bug reports..
> 
> Cheers,
> David
> 
> 
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