[postgis-tickets] [PostGIS] #2391: TopoGeo_AddPolygon splits again on second call

[PostGIS]

#2391: TopoGeo_AddPolygon splits again on second call
----------------------+-----------------------------------------------------
 Reporter:  robe      |       Owner:  strk         
     Type:  defect    |      Status:  new          
 Priority:  medium    |   Milestone:  PostGIS 2.2.0
Component:  topology  |     Version:  2.1.x        
 Keywords:            |  
----------------------+-----------------------------------------------------
 strk,

 Not sure if this is related to issue #2273 I complained about.

 I'm running this (I have the postgres.backend issue if you are wondering
 why I can't upgrade to 2.2.0dev for PostGIS part.
 {{{
 POSTGIS="2.2.0dev r11710" GEOS="3.4.0dev-CAPI-1.8.0 r3846" PROJ="Rel.
 4.8.0, 6 March 2012" GDAL="GDAL 1.10.0, released 2013/04/24"
 LIBXML="2.7.8" LIBJSON="UNKNOWN" TOPOLOGY RASTER PostgreSQL 9.3beta2,
 compiled by Visual C++ build 1600, 64-bit
 }}}

 and I tried with my PostgreSQL 9.2 64-bit install too and have the same
 issue.

 Anyway I'm puzzled by this to recreate

 run the attached ch08_staging (for the record data is the city boundary
 file from here http://www.victoria.ca/EN/main/city/open-data-
 catalogue.html)


 {{{
 SELECT CreateTopology('ch08_topology',4326);
 SELECT gid, TopoGeo_AddLineString('ch08_topology', geom) As edge_id
 FROM (SELECT gid, (ST_Dump(geom)).geom
  FROM ch08_staging.cityboundary
 ) As f;
 }}}

 {{{
 -- outputs --
 gid | edge_id
 1,1

 }}}


 {{{
 SELECT topologysummary('ch08_topology');
 }}}

 outputs:

 {{{
                   topologysummary
 ----------------------------------------------------
  Topology ch08_topology (1), SRID 4326, precision 0+
  1 nodes, 1 edges, 1 faces, 0 topogeoms in 0 layers+
 }}}

 run the add again

 {{{
 SELECT gid, TopoGeo_AddLineString('ch08_topology', geom) As edge_id
 FROM (SELECT gid, (ST_Dump(geom)).geom
  FROM ch08_staging.cityboundary
 ) As f;
 }}}

 Get output:

 {{{
  gid | edge_id
 -----+---------
    1 |       1
    1 |       2
 }}}


 Where did edge_id 2 come from.
 {{{
 SELECT topologysummary('ch08_topology');
 }}}

 outputs:

 {{{
                   topologysummary
 ----------------------------------------------------
  Topology ch08_topology (1), SRID 4326, precision 0+
  2 nodes, 2 edges, 1 faces, 0 topogeoms in 0 layers+
 }}}

 Is this a bug or just an occupational hazard with tolerances?
 Unfortunately if I repeat the above exercise with something like
 I still get an additional split the second call.

 {{{
 SELECT gid, TopoGeo_AddLineString('ch08_topology', geom, 0.0001) As
 edge_id
 FROM (SELECT gid, (ST_Dump(geom)).geom
  FROM ch08_staging.cityboundary
 ) As f;

 }}}

 I've also tested on 2.1.0 and have same issue, but haven't tested on 2.0.

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/2391>
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