Union shapes, Side location conflict

Developer
Jul 1, 2013 at 5:51 PM
I'm unioning a shape with this line:

FirstLevCtchmentsArea = reconsCatches.UnionShapes(ShapeRelateType.All);

and get this toplogy exception:

Side location conflict at [ DotSpatial.Topology.Coordinate ]

The underlying union is on NHDPlus catchments.

Anything I can do to avoid this error?