[geos-devel] [GEOS] #665: st_isvalid fails to detect invalid interior ring orientation

[GEOS]

#665: st_isvalid fails to detect invalid interior ring orientation
------------------------+---------------------------------------------------
 Reporter:  vmo         |       Owner:  geos-devel@…              
     Type:  defect      |      Status:  new                       
 Priority:  major       |   Milestone:  3.4.3                     
Component:  Default     |     Version:  3.3.3                     
 Severity:  Unassigned  |    Keywords:                            
------------------------+---------------------------------------------------
 The following request should return False (the interior ring as the same
 orientation as the exterior ring)

 select st_isvalid(st_geomfromtext('polygon((0 0, 1 0, 1 1, 0 1, 0 0),(.1
 .1, .9 .1, .9 .9, .1 .9, .1 .1))'));

 But it returns True.



 From Simple Feature Access - Part 1 (1.2.1), section 6.1.11:

 The exterior boundary LinearRing defines the “top” of the surface which is
 the side of the surface from which the
 exterior boundary appears to traverse the boundary in a counter clockwise
 direction. '''The interior LinearRings will have the opposite orientation,
 and appear as clockwise when viewed from the “top”,'''

-- 
Ticket URL: <http://trac.osgeo.org/geos/ticket/665>
GEOS <http://geos.refractions.net/>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).