[geos-devel] Fwd: st_buffer crashes server

[Sandro Santilli]

On Tue, Dec 04, 2012 at 12:54:43PM +0200, Gražvydas Valeika wrote:
> On Tue, Dec 4, 2012 at 11:54 AM, Sandro Santilli <strk at keybit.net> wrote:
> 
> > If you want to help further you could find a smaller version of
> > that input still triggering the bug.
> 
> my naively minimized sample which still crashes on my Fedora and Win
> environments (didn't try on Scientific Linux):

Thanks. I've a 26 vertices reduction on trac.
That's the best place to continue this:
http://trac.osgeo.org/geos/ticket/605

I think the problem is a robustness issue in PlanarGraph building.
Fixing it won't be easy, but I guess we could just throw a TopologyException
thus allowing higher levels to try some heuristic to fix that.

Unfortunately the heuristic used results in an extreme loss of precision,
finally giving a buffer which is very unlikely to be what you're looking for.
More info on the tracker.

I'm currently trying to setup a testcase for PlanarGraph building.
It strikes me that there's no unit testing for that even in JTS...

--strk;