[geos-devel] strange behaviour of LinearRing::within()

Martin Davis mbdavis at refractions.net
Tue Jun 12 17:14:11 EDT 2007


I suspect this is because you are expecting linear rings to "contains" 
the area they enclose. But this is not how linear rings are defined - 
they are 1-dimensional features, not areal ones.  A linear ring would 
only be "within" another one if its linework lay exactly on top of the 
other one's linework.   GEOS is behaving correctly, according to the SFS 
geometry model.

Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022

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