boost::geometry::intersection algorithm returning invalid geometry for double

Open vschoech opened this issue 8 months ago • 1 comments

My tc::geo::polygon type is actually a multi-polygon, using a polygon type that is based on double, oriented counter-clockwise and open (not closed). I am using boost 1.87.0.

We compile with Microsoft Visual C++ 2022 for x86 (Win32), using the /fp:fast flag. The issue is also reproducible when compiling for the x64 platform.

Please consider the following example:

tc::geo::polygon<double> polygonA;
boost::geometry::read_wkt("MULTIPOLYGON(((2601.6180555555557 201.34722222222223,2601.6180555555557 582.8472222222223,372.41666666666663 1065.3993055555554,372.41666666666663 201.34722222222223,2601.6180555555557 201.34722222222223)))", polygonA); // does not throw
boost::geometry::is_valid(polygonA); // returns true

tc::geo::polygon<double> polygonB;
boost::geometry::read_wkt("MULTIPOLYGON(((2482.777777777778 201.34722222222223,2400.270833333333 1421.5416666666665,1983.1944444444443 1421.5416666666665,1900.6875 201.34722222222223,2482.777777777778 201.34722222222223)))", polygonB); // does not throw
boost::geometry::is_valid(polygonB); // returns true

tc::geo::polygon<double> polygonC;
boost::geometry::intersection(polygonA, polygonB, polygonC); // does not throw
// polygonC: MULTIPOLYGON(((2482.777777777778 201.34722222222223,2482.777777777778 201.34722222222217,2454.8330485880297 614.621565835736,1936.2231963642907 726.8843097381582,1900.6875 201.34722222222223,2482.777777777778 201.34722222222223)))
boost::geometry::is_valid(polygonC); // returns false!

The intersection of two valid multi-polygons yields an invalid multi-polygon.