Subject: [ggl] Polygon difference
From: Vish (vrang3)
Date: 2011-01-09 21:35:03
I get an empty polygon list from a polygon difference calculation 'a NOT
b'. Neither polygon 'a' nor 'b' has a hole and 'b' is completely inside
'a'. Polygons 'a' and 'b' are passed into an intersection_inserter after
reversing the boundary of 'b'.
I read the posting of Feb 28, 2010 titled "XOR and/or DIFFERENCE boolean
polygon combination". In that posting, a problematic case was described,
when rings of 'b' do not intersect rings of 'a'. It was mentioned that
some additional work needed to be done to assemble the rings.
Does this problematic case remain unresolved, and if so, is there a
Geometry list run by mateusz at loskot.net