[postgis-users] Topological Exceptions

[Paul Ramsey]

Hard. An "ERROR()" geometry type is almost called for, so that you can
run the whole set and actual inspect post-facto which ones failed.
The most annoying part of the current behavior for me is the
difficulty tracking down the problematic pair of geometries.  I think
you're right, the current fail-and-stop behavior causes more problems
than it solves.

On 3/11/08, Obe, Regina <robe.dnd at cityofboston.gov> wrote:
>
>
> I've been doing a lot of work using ST_Intersection, ST_Difference, ST_Union
> etc to cut out slices of geometries I don't want and slicing up geometries
> into smaller pieces, reunioning etc.
>
> I've been running into a lot of Topological Exceptions of the form directed
> Edge this and non-noded that.  For the most part I've been able to overcome
> these by slicing things smaller or skipping over problem regions (e.g. areas
> where the difference is a line or point or something of that sort).
>
> I think a lot of people have run into the same issues and have gotten
> frustrated and there doesn't seem to be a simple solution suggested to
> overcome these.
>
> Is there any way we can change (add overloaded functions or some setting
> parameter) - that take additional parameters to simply ignore these errors
> that says return empty collection or NULL when a GEOS error is thrown.  That
> way I can simply ignore these and throw them out of my equation and move on.
>
> Just a thought.  I'm sure my suggestion is rather simple-minded and I'm sure
> I'm missing some reason of why this is not feasible.  An explanation of why
> my suggestion is stupid at anyrate would be nice.
>
> Thanks,
> Regina
>
>
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