[postgis-devel] [PostGIS] #701: Support for 9.1 KNN GIST enhancements

PostGIS trac at osgeo.org
Tue Oct 25 08:19:38 PDT 2011


#701: Support for 9.1 KNN GIST enhancements
-------------------------+--------------------------------------------------
 Reporter:  robe         |       Owner:  pramsey      
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.0.0
Component:  postgis      |     Version:  trunk        
 Keywords:               |  
-------------------------+--------------------------------------------------

Comment(by markstos):

 Thanks for your work on this, pramsey.

 I currently use PostgreSQL to run over a million geo-spatial searches per
 day for "points near a zipcode" using functions like "cube_distance()" and
 "earth_box()". Below is an example of the kind of method I'm using. Is
 your work a viable replacement for this use case? If it appears to be, I'm
 happy to peer review the results vs my current method, and benchmark the
 two alternatives.

 Here's pseudo-SQL for our current use:


 {{{
  SELECT *
          , cube_distance( center.earth_coords ,
 postal_codes.earth_coords)/$meters_per_mi AS distance
          , 'Miles' AS units
  FROM (
          SELECT
              earth_coords,
              earth_box( earth_coords , $radius*$meters_per_mi ) as
 center_box
          FROM zipcodes WHERE zipcode = '47374'
       ) as center,
      addresses
      JOIN zipcodes USING (zipcode)
  ORDER BY distance ASC
 }}}

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/701#comment:7>
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