[geos-devel] Noding linework

Sandro Santilli strk at keybit.net
Fri Jul 15 06:06:07 EDT 2011

On Thu, Jul 14, 2011 at 08:17:55PM -0700, Martin Davis wrote:
> Yes, union() is supposed to fully node linework.
> This case works fine in JTS 1.11 (and JTS 1.12) - i.e. running the
> equivalent of polygonize( union( boundary(A),  B).  The output from
> the union checks out as being fully noded, and the polygonize
> produces 2 valid polygons.
> So possibly this is one of those numerical issues which shows up in
> GEOS in native code, but not in JTS in Java?  This maybe one of
> those cases where GEOS and JTS need to be traced through in parallel
> (which seems really painful, but I think you've done this in the
> past, right?)

Right, and it was a scary place to be :/
I'm currently going after another similar issue, and looks like it's
still being about line intersection.

I took the chance to review the unit tests and found
that we had in GEOS a few test from
commented out as they failed:

 - testDaveSkeaCase
 - testCmp5CaseWKT
 - testCmp5CaseRaw

They all still fail in GEOS !

Not sure they succeed in JTS though, as I seem to be unable to run
unit tests there. I tried:

 $ ant junit
 Buildfile: build.xml

    [delete] Deleting directory /home/src/jts/jts/jts/${build.classes}
     [mkdir] Created dir: /home/src/jts/jts/jts/${build.classes}

 /home/src/jts/jts/jts/build.xml:189: srcdir "/home/src/jts/jts/jts/${base.src}" does not exist!
 Total time: 0 seconds

Ideas ?


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