[geos-devel] Noding linework

[Martin Davis]

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?)

Martin

On 7/14/2011 9:26 AM, Sandro Santilli wrote:
> Martin, isn't Union operation supposed to fully node
> input linework ? The bug I just filed (and then closed)
> on JTS about Polygonize failure was produced with Union
> but wasnt' fully noded...
>
> Unioning again the return from Union made it noded !!
>
> See http://trac.osgeo.org/postgis/ticket/1115
> for further details.
>
> Any ideas ?
>
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