GPS radius search with Php 5 and MySQL

I have a PlaceID | PlaceName | Lat | Lon as my database structure.

Say I have my current latitude and longitude as

$lat = "37.331862";
$lon = "-122.029937";

I want to find places that are i开发者_如何学JAVAn a 100 feet radius. Might allow the user to choose.

You may be interested in checking out the following presentation:

• Geo/Spatial Search with MySQL¹ by Alexander Rubin

The author describes how you can use the Haversine Formula in MySQL to order by proximity and limit your searches to a defined range. He also describes how to avoid a full table scan for such queries, using traditional indexes on the latitude and longitude columns.

¹ PDF Version