[postgis-devel] [PostGIS] #285: FAQ When should I user geography over geometry

PostGIS trac at osgeo.org
Fri Nov 6 02:19:25 PST 2009

#285: FAQ When should I user geography over geometry
 Reporter:  robe     |       Owner:  pramsey      
     Type:  task     |      Status:  new          
 Priority:  medium   |   Milestone:  postgis 1.5.0
Component:  postgis  |     Version:  trunk        
 Keywords:           |  
 Someone asked me this and it sounds like a question we will be getting
 often from both novices as well as existing users.

 I was thinking in the geography side of things -- could whip up a feature
 matrix (an autogenerated one with some xsl voodoo magic that)

 For each function that takes as input geography/geometry mark off whether
 it supports geometry/geography  like  with T meaning it uses a geometry
 transform operation so not native and yes/no being native or non-existent.
 We can put a special tag in each function description to easily pull the
 transform question out.

 function   geometry    geography
 ST_Buffer   yes         T
 ST_Distance yes        yes
 ST_DWithin  yes        yes

 Then we need the descriptive FAQ of what geometry/geography offers from a
 performance/use case perspective I guess.  E.g. support by third party
 tools and loaders etc.  What range (are you dealing with regional or all
 over the world)  -- etc.

 So kind of like a questionaire type thing to consider before using one or
 the other.

Ticket URL: <http://trac.osgeo.org/postgis/ticket/285>
PostGIS <http://trac.osgeo.org/postgis/>

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