[postgis-tickets] [PostGIS] #2173: ST_Split fails to split on existing vertex

[PostGIS]

#2173: ST_Split fails to split on existing vertex
---------------------+------------------------------------------------------
 Reporter:  strk     |       Owner:  pramsey      
     Type:  defect   |      Status:  new          
 Priority:  medium   |   Milestone:  PostGIS 2.0.3
Component:  postgis  |     Version:  2.0.x        
 Keywords:           |  
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 This bug was found in #2172 as it affects topology building.
 In that case a line (899.112421269008 units long) gets splitted by one if
 its vertices which is around halfway into it:
 {{{
 select st_line_locate_point(geom, st_pointn(geom, 745))
  from offending;
     0.692338478022024
 }}}

 The return from ST_Split, unioned back togheter, does NOT give the
 original geometry back.

 This is most likely due to the fact that the split is not occurring
 exactly where the original vertex is but rather on a close-by point which
 results in snapping a segment on the new point.

-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/2173>
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