[geos-devel] RE: GEOS errors from PostGIS

[Martin Davis]

Different code, but probably the same cause.  Due to the complexities of 
computing line segment intersections, unless special measures are take, 
TopologyExceptions can occur in some situations (and are most likely in 
the kind of situation you mentioned, where you have a lot of segments 
which are nearly but not perfectly coincident).  The new code in the JTS 
UnaryUnionOp is meant to reduce the likelihood of these failures.


On 1/16/2011 4:36 PM, James.Sewell at lisasoft.com wrote:
> If UnaryUnionOp is not ported would that mean I am hitting a different bug to the Unary Union bug mentioned in the thread below?
>
> Cheers,
> James Sewell 
> Developer 
> LISAsoft 
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> -----Original Message-----
> From: geos-devel-bounces at lists.osgeo.org [mailto:geos-devel-bounces at lists.osgeo.org] On Behalf Of strk
> Sent: Sunday, 16 January 2011 6:55 PM
> To: Martin Davis
> Cc: geos-devel at lists.osgeo.org
> Subject: Re: [geos-devel] RE: GEOS errors from PostGIS
>
> On Fri, Jan 14, 2011 at 05:37:05PM -0800, Martin Davis wrote:
>> Yes, I know it's a bad msg - it was a slip when commiting.  Too late to
>> change now though.
> Ok, reviewed... UnaryUnionOp is still unported to GEOS,
> all the rest is up to date.
>
> If anyone is willing to sponsor the port I'm available.
>
> --strk;
>
>    ()   Free GIS&  Flash consultant/developer
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