[postgis-devel] [PostGIS] #1571: ST_ChangeEdgeGeom lets you break topology

PostGIS trac at osgeo.org
Fri Feb 17 00:35:03 PST 2012

#1571: ST_ChangeEdgeGeom lets you break topology
 Reporter:  strk      |       Owner:  strk         
     Type:  defect    |      Status:  new          
 Priority:  medium    |   Milestone:  PostGIS 2.0.0
Component:  topology  |     Version:  trunk        
 Keywords:            |  
Changes (by strk):

  * milestone:  PostGIS 2.1.0 => PostGIS 2.0.0


 Replying to [comment:5 strk]:

 > Next step would be algorithmically: how to find out if the constraint
 gets broken by a movement ?

 A night over it and here's the answer: form a polygon merging old and new
 edge, if the polygon contains any node then the movement broke the
 constraint. Corner case: a closed edge changing winding (must be treated

 I can do it for 2.0 !

Ticket URL: <http://trac.osgeo.org/postgis/ticket/1571#comment:6>
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