Filed with boost trac:
https://svn.boost.org/trac/boost/ticket/10661
Regards
Volker
--
Volker Schöch | vschoech@think-cell.com
Senior Software Engineer
From: Geometry [mailto:geometry-bounces@lists.boost.org]
On Behalf Of Volker Schöch
Sent: Dienstag, 14. Oktober 2014 11:55
To: Boost.Geometry library mailing list (geometry@lists.boost.org)
Subject: [geometry] difference algorithm returning invalid geometry
I am about to file this as a bug report, but given the discussion here I think it makes sense to have someone review the issue first.
My “polygon” type is actually a
multi-polygon. It is oriented counter-clockwise and not closed, my point type is based on
int.
_intPolygon
polygonA;
boost::geometry::read_wkt("MULTIPOLYGON(((1701
985,3501 985,3501 2785,1701 2785,1701 985)))", polygonA);
// does not throw
boost::geometry::is_valid(polygonA);
// returns true
_intPolygon
polygonB;
boost::geometry::read_wkt("MULTIPOLYGON(((1698
1860,1698 1122,2598 1392,3492 1842,3492 32706,2598 2340,1698 1860)))", polygonB);
// does not throw
boost::geometry::is_valid(polygonB);
// returns true
_intPolygon
polygonC;
boost::geometry::difference(polygonA, polygonB, polygonC);
// does not throw
// polygonC == MULTIPOLYGON(((1701 1122,1701 985,3501 985,3501 2785,3492 1857,3492 1842,2598 1392,1701
1122)),((1701 1861,2598 2340,1669 2785,1701 2785,1701 1861)))
boost::geometry::is_valid(polygonC);
// returns false!
_intPolygon
polygonD;
boost::geometry::read_wkt("MULTIPOLYGON(((1698
2772,1698 1860,2598 2340,3492 2412,3492 32743,1698 2772)))", polygonD);
// does not throw
boost::geometry::is_valid(polygonD);
// returns true
_intPolygon
polygonE;
boost::geometry::difference(polygonC, polygonD, polygonE);
// throws "Boost.Geometry Overlay invalid input exception"!
Any suggestions or comments are greatly appreciated.
Thanks
Volker
--
Volker Schöch | vschoech@think-cell.com
Senior Software Engineer
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