note rinceWind <p>We've encountered this requirement for [http://openguides.org]. Here, alongside the lat + long, we store planar X-Y coordinates in the database, using a projection such as UTM or Ordnance Survey. Then, we use Pythagoras in SQL queries to find all entries within the distance.</p> <p>This works well for city guides - our main application, but less well over large distances, where curvature of the oblate spheroid that is the Earth, becomes a factor.</p> <p>I don't know what your application is, but check out [dist://OpenGuides], as there's probably quite a bit of code you can reuse. Or even set up a Guide yourself, if that's what you are trying to achieve.</p> <!-- Node text goes above. Div tags should contain sig only --> <div class="pmsig"><div class="pmsig-144850"> <p><small>--<br /><br />Oh Lord, won’t you burn me a Knoppix CD ?<br /> My friends all rate Windows, I must disagree.<br /> Your powers of persuasion will set them all free,<br /> So oh Lord, won’t you burn me a Knoppix CD ? <br /> <em>(Missquoting Janis Joplin)</em></small></p> </div></div> 601377 601377