[postgis-devel] [PostGIS] #1778: ST_CollectionExtract: inconsistent EMPTY results

[PostGIS]

#1778: ST_CollectionExtract: inconsistent EMPTY results
---------------------+------------------------------------------------------
 Reporter:  strk     |       Owner:  pramsey      
     Type:  defect   |      Status:  new          
 Priority:  medium   |   Milestone:  PostGIS 2.0.1
Component:  postgis  |     Version:  2.0.x        
 Keywords:           |  
---------------------+------------------------------------------------------
 {{{
 strk=# select ST_AsEWKT(ST_CollectionExtract('LINESTRING EMPTY', 2));
     st_asewkt
 ------------------
  LINESTRING EMPTY
 (1 row)

 strk=# select ST_AsEWKT(ST_CollectionExtract('GEOMETRYCOLLECTION EMPTY',
 2));
        st_asewkt
 -----------------------
  MULTILINESTRING EMPTY
 (1 row)
 }}}

 Why is it a _single_ empty in the first case but a _multi_ empty in the
 second ? How to transform a multi to a simple ? (ST_Homogenize missing)

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1778>
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