[postgis-devel] [PostGIS] #1776: ST_SymDifference involging EMPTY not symmetric

[PostGIS]

#1776: ST_SymDifference involging EMPTY not symmetric
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 Reporter:  strk     |       Owner:  pramsey      
     Type:  defect   |      Status:  new          
 Priority:  medium   |   Milestone:  PostGIS 2.0.1
Component:  postgis  |     Version:  2.0.x        
 Keywords:           |  
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Comment(by strk):

 The code shows this as being intentional:

 {{{
         /* A.SymDifference(Empty) == A */
         if ( lwgeom_is_empty(geom2) )
                 return lwgeom_clone(geom1);

         /* Empty.DymDifference(B) == Empty */
         if ( lwgeom_is_empty(geom1) )
                 return lwgeom_clone(geom1);
 }}}

 What's the rationale for the second ??? I think it's just plain wrong !

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1776#comment:2>
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