[postgis-devel] [PostGIS] #1976: ST_Intersects() returns false while ST_Intersection returns a geography

[PostGIS]

#1976: ST_Intersects() returns false while ST_Intersection returns a geography
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  Reporter:  mhiper3pg  |       Owner:  pramsey      
      Type:  defect     |      Status:  reopened     
  Priority:  medium     |   Milestone:  PostGIS 1.5.6
 Component:  postgis    |     Version:  1.5.X        
Resolution:             |    Keywords:               
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Comment(by pramsey):

 OK, so the speed difference is because between 1.5 and 2.0 we switched
 from passing boxes into the distance function as part of the signature to
 letting them ride in implicitly on the lwgeom objects. The trouble with
 the latter is that the distance function recursively unwraps the
 geometries, so that when collections get unwrapped, the lwgeom of their
 sub-geometries that get passed into the next call DO NOT HAVE boxes
 defined. So they get calculated on the fly, expensively. We need an
 lwgeom_add_box_deep to add boxes all the way down into lwgeoms for each
 element.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1976#comment:7>
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