Changes between Version 5 and Version 6 of UsersWikiplpgsqlfunctionsDistance

Timestamp:

Sep 29, 2009, 9:24:16 PM (15 years ago)

Author:

robe

Comment:

—

UsersWikiplpgsqlfunctionsDistance

@@ -3 +3 @@
  * '''An ST_Dwithin like function that uses indexes for degree point data'''
 [http://www.postgis.org/pipermail/postgis-users/2009-June/023711.html]
+
+Caveat from newsgroup: Here's a simple 80/20 solution for people with lon/lat tables of
+points wanting to do distance searches.  It only works for places less
+than 60degrees north or south, and only for points. If you know your
+data is all more southerly than 60d, adjust the constant factor to
+make the index portion of the search more selective (and hence,
+efficient (faster)).
+
 {{{
 #!sql