[postgis-devel] [PostGIS] #1625: ST_Within and ST_DWithin disagree

PostGIS trac at osgeo.org
Wed Feb 29 00:21:55 PST 2012

#1625: ST_Within and ST_DWithin disagree
 Reporter:  strk     |       Owner:  pramsey      
     Type:  defect   |      Status:  new          
 Priority:  medium   |   Milestone:  PostGIS 2.0.0
Component:  postgis  |     Version:  trunk        
 Keywords:           |  

Comment(by strk):

 Please go ahead with the wiki page. I'm sure ST_Distance doesn't want a
 tolerance and yes I do see that ST_ClosestPoint maybe be at a non-zero
 Distance by doing that. I think we need to take for granted that _adding_
 a point on a line can't be on the original line, except rare occasions.
 Our space is not infinite. I think it is important not to try pretending

 Yeah the expanding float grid is an interesting concept. May be worth an
 internal function to compute it. Does sound like a reprojection issue
 doesn't it ? :)

Ticket URL: <http://trac.osgeo.org/postgis/ticket/1625#comment:10>
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