[postgis-tickets] [PostGIS] #3280: Almost collinear edges prevent adding a copy of existing edge

[PostGIS]

#3280: Almost collinear edges prevent adding a copy of existing edge
-----------------------+---------------------------
  Reporter:  strk      |      Owner:  strk
      Type:  defect    |     Status:  new
  Priority:  medium    |  Milestone:  PostGIS 2.1.9
 Component:  topology  |    Version:  2.0.x
Resolution:            |   Keywords:  robustness
-----------------------+---------------------------

Comment (by strk):

 It's to be noted that the center vertex of the L-shaped line is so close
 to the straight line that ST_Distance returns 0, still ST_Within returns
 false:

 {{{
 strk=# select ST_Distance(ST_PointN(e11.geom, 2), e10.geom) from
 bug3280.edge e11, bug3280.edge e10 where e11.edge_id = 11 and e10.edge_id
 = 10;
  st_distance
 -------------
            0
 (1 row)

 strk=# select ST_Within(ST_PointN(e11.geom, 2), e10.geom) from
 bug3280.edge e11, bug3280.edge e10 where e11.edge_id = 11 and e10.edge_id
 = 10;
  st_within
 -----------
  f
 (1 row)
 }}}

--
Ticket URL: <http://trac.osgeo.org/postgis/ticket/3280#comment:4>
PostGIS <http://trac.osgeo.org/postgis/>
The PostGIS Trac is used for bug, enhancement & task tracking, a user and developer wiki, and a view into the subversion code repository of PostGIS project.