[postgis-tickets] [PostGIS] #3401: ST_ModEdgeSplit makes topology invalid

[PostGIS]

#3401: ST_ModEdgeSplit makes topology invalid
-----------------------+---------------------------
  Reporter:  strk      |      Owner:  strk
      Type:  defect    |     Status:  new
  Priority:  blocker   |  Milestone:  PostGIS 2.2.1
 Component:  topology  |    Version:  trunk
Resolution:            |   Keywords:  32bit
-----------------------+---------------------------

Comment (by strk):

 Here, test with only ST_Split:
 {{{
 =# with inp as ( SELECT 'LINESTRING(-180 0,0 0)'::geometry a, 'POINT(-20
 0)'::geometry b ), op as ( select a,b,st_split(a,b) s from inp ), dumped
 as ( select a,b,(st_dumppoints(s)).* from op ) select path,
 st_astext(geom) endpoint, st_astext(b) split, st_equals(geom,b),
 st_contains(a,b) from dumped;
  path  |   endpoint    |    split     | st_equals | st_contains
 -------+---------------+--------------+-----------+-------------
  {1,1} | POINT(-180 0) | POINT(-20 0) | f         | t
  {1,2} | POINT(-20 0)  | POINT(-20 0) | f         | t
  {2,1} | POINT(-20 0)  | POINT(-20 0) | f         | t
  {2,2} | POINT(0 0)    | POINT(-20 0) | f         | t
 (4 rows)
 }}}

 None of the endpoints of the split output equal the split point, although
 the split point is contained in the originally splitted line...

--
Ticket URL: <https://trac.osgeo.org/postgis/ticket/3401#comment:14>
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.