[Qgis-developer] [geos-devel] Bug with avoid intersection - willing to fund fix

[George Silva]

Hello Sandro.

I dont think this is a GEOS bug. I was following the various discussions on
this bug/unexpected behavior.

On one of them, in discussion with Marco, you said that it might be a
problem with GEOSDifference. And after that theres our chat in IRC, which
seems to fit the problem.

We can easily test this inserting the geometries directly in Postgis, I
mean, the result of an ST_Difference.

Im not sure where the bug resides, but I would like to come up with
alternatives, or at least a very clear method of constructing these
polygons in Qgis that will not result in errors.

It seems to me that if the new polygon only intersects another one, works,
but that is not always the case when doing land use maps.

The plain simple test that Qgis MUST pass is that polygons created with
avoid intersections options, should have NO topological errors.

Im just travelling right now, but we'll come up with test cases.

Anyone on Qgis community has any ideas?

Thanks everyone
Em 08/11/2013 07:41, "Sandro Santilli" <strk at keybit.net> escreveu:
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