On Fri, Mar 19, 2004 at 17:05:11 +0700, David Garamond <[EMAIL PROTECTED]> wrote: > Imagine an Orkut-like site. Suppose we have 'person' table of 100k > people. About 75% of these people fill in their location > (City/State/Country) information. We also have a 'city' table containing > list of cities with their state & country and each city's > latitude/longitude. Assume all people's location is registered in the > 'city' table. > > How does one design a database to be able to process "Show me people > that live no farther than 250 miles from where I live" quickly? I can do > "Show me people that live within (A-X to A+X) latitude and (B-X to B+X) > longitude" though. (Where A and B is the latitude and longitude [of the > person], and X is some numeric value.
The earthdistance contrib package allows you to do these kinds of queries with gist indexes. This might be a simpler solution than using PostGIS which has a lot of other features you don't appear to be using. ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])