[geos-devel] Re: [GEOS] #527: Union and UnaryUnion both fail at correctly node input lines

[GEOS]

#527: Union and UnaryUnion both fail at correctly node input lines
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 Reporter:  strk        |       Owner:  geos-devel@…              
     Type:  defect      |      Status:  new                       
 Priority:  major       |   Milestone:  3.3.4                     
Component:  Default     |     Version:  3.3.3                     
 Severity:  Unassigned  |    Keywords:                            
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Comment(by strk):

 A second attempt at checking for correct noding: compute intersection
 matrix between each pair of lines. Expected outcome: interior/interior
 intersection is always false in a correctly noded arrangement.

 This confirms UnaryUnion isn't correctly noding:
 {{{
 with noded as (
  select ST_UnaryUnion(
 'LINESTRING(1725063 4819121,1725104 4819067,1725060
 4819087,1725064.14183882 4819094.70208557,1725064.13656044
 4819094.70235069,1725064.14210359 4819094.70227252,1725064.14210362
 4819094.70227252,1725064.13656043 4819094.70235069,1725055 4819094,1725055
 4819094,1725055 4819094,1725063 4819121)'
  ) as g ),
 dumped as (  select (st_dump(g)).* from noded ),
 matrices as ( select a.path as ap, b.path as bp, st_relate(a.geom, b.geom,
 2) as im
            from dumped a, dumped b where a.path < b.path)
 select ap, bp, im from matrices where ST_RelateMatch(im, 'T********');
  ap  | bp  |    im
 -----+-----+-----------
  {1} | {2} | 0F1F00102
  {2} | {5} | 1F1F00102
 (2 rows)
 }}}

 So first and second line have puntual interior/interior intersection,
 while second and fifth line have lineal interior/interior intersection.
 Shouldn't happen, right ?

-- 
Ticket URL: <http://trac.osgeo.org/geos/ticket/527#comment:3>
GEOS <http://geos.refractions.net/>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).