[postgis-devel] [PostGIS] #785: Topology functions should be tolerance aware

[PostGIS]

#785: Topology functions should be tolerance aware
-------------------------+--------------------------------------------------
 Reporter:  robe         |       Owner:  strk         
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.0.0
Component:  topology     |     Version:  trunk        
 Keywords:               |  
-------------------------+--------------------------------------------------
 In testing functions like ST_NewEdgesSplit, I am reminded that the
 topology functions don't seem to consider the tolerance that was put in
 for a topology.

 For example I created a topology with tolerance of 0.5 meters.

 e.g. if I had an edge like this

 {{{
 ST_GeomFromText('LINESTRING(227575.8 893917.2,227591.9 893900.4)', 26986);
 }}}

 And tried to split at

 {{{
 ST_GeomFromText('POINT(227578.909683258 893913.955113122)', 26986)
 }}}

 I get an error its not on the line yet if I take the distance between the
 2 --


 {{{
 SELECT ST_Distance(ST_GeomFromText('POINT(227578.909683258
 893913.955113122)', 26986), ST_GeomFromText('LINESTRING(227575.8
 893917.2,227591.9 893900.4)', 26986));
 }}}

 I get 0.

 Wondering if we should replace our use of ST_Within when comparing a
 linetring to a point (and ST_Intersects) with ST_DWithin(,,tolerance)

 Or are there changes in GEOS that will make this work?

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/785>
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