[postgis-tickets] [PostGIS] #3838: topology.toTopoGeom fails with ERROR: XX000: SQL/MM Spatial exception - geometry crosses, when using tolerance 10 meter

[PostGIS]

#3838: topology.toTopoGeom fails with ERROR:  XX000: SQL/MM Spatial exception -
geometry crosses,  when using tolerance 10 meter
-------------------------+-------------------------------------------------
  Reporter:  laopsahl    |      Owner:  strk
      Type:  defect      |     Status:  assigned
  Priority:  medium      |  Milestone:  PostGIS 2.3.4
 Component:  topology    |    Version:  2.3.x
Resolution:              |   Keywords:  totopogeom, ERROR:  XX000: SQL/MM
                         |  Spatial exception - geometry crosses
-------------------------+-------------------------------------------------

Comment (by strk):

 Relevant debug lines:
 {{{
 DEBUG:  [lwgeom_topo.c:_lwt_AddLine:5691] Working tolerance:10
 DEBUG:  [lwgeom_topo.c:_lwt_AddLine:5706] Noded: LINESTRING(622608
 6554988,622596 6554984)
 DEBUG:  [lwgeom_topo.c:_lwt_toposnap:451] It took 4/6 iterations to
 properly snap
 DEBUG:  [lwgeom_topo.c:_lwt_AddLine:5759] Snapped: LINESTRING(622591.53
 6554995.96,622598.73 6554996.23,622606.83 6554996.14,622609.17
 6554995.51,622617.12 6554996.14,622612.06 6554996.7,622596 6554984)
 }}}

 Basically the recursive snapping with a tolerance of 10 ends up snapping
 to 4 of the 6 vertices in the intersecting edge, generating an invalid
 edge.

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Ticket URL: <https://trac.osgeo.org/postgis/ticket/3838#comment:6>
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