[postgis-devel] [PostGIS] #475: ST_Simple should return false with duplicate points

[PostGIS]

#475: ST_Simple should return false with duplicate points
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 Reporter:  kneufeld  |       Owner:  pramsey      
     Type:  defect    |      Status:  new          
 Priority:  low       |   Milestone:  PostGIS 2.0.0
Component:  postgis   |     Version:  trunk        
 Keywords:            |  
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 The OGS specs state: ''"has no anomalous geometric points, such as self
 intersection or self tangency"'' and ''"is simple if it does not pass
 through the same point twice"''. (2.1.5)

 The SQL/MM specs state: ''"is not simple if any interior point has the
 same location as another interior point or a point on the boundary"''
 (4.1.4)

 So, by definition then, this should return false.

 {{{
 select st_issimple(
   'LINESTRING(0 0, 1 1, 1 1)'::geometry
 );
  st_issimple
 -------------
  t
 (1 row)
 }}}

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/475>
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