UnboundLocalError: __lt__() in vis_graph.py

[TaipanRex]

same_point is not defined and should be. Initiate to None, then throw an exception if still None after the two if statements. There are instances where a point of a polygon is on the edge of another polygon. That means their distances are equal, but have no common points. same_point therefore does not exist...

[aranciokov]

if self.edge.p1 in other.edge:
  same_point = self.edge.p1
elif self.edge.p2 in other.edge:
  same_point = self.edge.p2

There's one thing I'm not sure about (which relates to this snippet).
Say we have self.edge = ((5.00, 4.00), (6.00, 3.00)) and other.edge = ((3.00, 0.00), (7.00, 4.00)).
When checking self.edge.p2 in other.edge you are checking (6.00, 3.00) in ((3.00, 0.00), (7.00, 4.00)), right? It gives false (so it goes on and ignores the same_point = ...) and the point (6.00, 3.00) lays on the segment. Is this OK?

[TaipanRex]

I implemented Pyvisgraph with the assumption that all polygons are distinct, i.e. they do not overlap. That also means that the point of one polygon should not lie on the segment of another. Thats really the consequence here, the code snippet you linked should only be triggered when the two edges are of the same polygon, i.e. they share a common point and therefore their distance is equal.

[TaipanRex]

A solution is to use Shapely cascaded_union to merge overlapping polygons. That has solved it for one user.