Re: Postal code radius searches

On Wed, 6 Feb 2002, Milo Hyson wrote:

> figure out a fast way to locate all of the postal codes within an arbitrary
> radius of another postal code.

perhaps a "refined" brute force is ok :

1. take the point you want to calculate distances around

2. calculate the maximum and minimum latitude/longitude so that a city can
be nearer than your distance limit (equivalent to going x km/mi north,
south, east and west)

3. do a brute force search but limit yourself to the "square" (it's not
really square ;-) around your starting point.

If the distances are normally small, this should be able to use indexes on
the coordinates and probably be a lot faster already.

Hope this helps,
Tycho

--
Tycho Fruru tycho(dot)fruru(at)conostix(dot)com