id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
10823,IsValid or dissolve problem?,anonymous,Barend Gehrels,"Dear Boost Geometry contributors.

As always: Thanks for your great work. Your work is an incredible help every day.

I discovered a problem, which I guess you can help me with.

If you look at the below test case you will see a small polygon where two points touches each other and forms a ""hole"" in the polygon.

If I call is_valid with this polygon it tells me that the polygon is invalid.

If I then tries to dissolve it, the output is again not valid.

My question is therefore if it could be a problem with is_valid or dissolve. Alternatively what could I do to make it valid so that it can be used for calls to e.g sym_difference?

Thanks a lot

Johan

BOOST_AUTO_TEST_CASE(Boost_IsValidOrDissolve_Fails)
{
  polygon<point_xy<float>> Poly;
  read_wkt(""POLYGON((0 3, 3 3, 3 1, 2 1, 2 2, 1 2, 1 1, 2 1, 2 0, 0 0, 0 3))"", Poly);

  BOOST_CHECK(!is_valid(Poly));

  multi_polygon<polygon<point_xy<float>>> Polys;
  dissolve(Poly, Polys);

  BOOST_CHECK(!is_valid(Polys));
}
",Bugs,closed,To Be Determined,geometry,Boost 1.57.0,Problem,wontfix,,mkaravel