[postgis-devel] [PostGIS] #1324: Provide a function to read an LWGEOM bounding box and stop reading it directly

[PostGIS]

#1324: Provide a function to read an LWGEOM bounding box and stop reading it
directly
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 Reporter:  strk     |       Owner:  pramsey      
     Type:  task     |      Status:  new          
 Priority:  medium   |   Milestone:  PostGIS 2.0.0
Component:  postgis  |     Version:  trunk        
 Keywords:           |  
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Old description:

> In order to simplify the code, we'd need a function that returns an
> LWGEOM's bounding box optionally caching it in the structure if not
> available.

New description:

 In order to simplify the code, we'd need a function that returns an
 LWGEOM's bounding box optionally caching it in the structure if not
 available.

 I belive computing the BBOX of a multigeometry by combining the rounded
 BBOX of component geometries should yeld the same numbers as computing
 everything using doubles and rounding only at the end, although the
 operation would be slightly less performance (could be impossible to note
 even by a performance analisys tool).

 Such new function could replace the public compute_bbox functions (there
 are 3 of them: wrapper, geodetic, cartesian) which could then be moved to
 the internal header.

--

Comment(by strk):

 An open question is if such method should also take care of rounding the
 BBOX to floats or not. Such rounding would serve the purpose of always
 having the _same_ BBOX for the _same_ geometry, no matter if the BBOX was
 read from the serialized format (which uses floats) or computed from the
 actual coordinates.

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/1324#comment:1>
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