On Thu, Sep 11, 2008 at 8:17 AM, tedd <tedd.sperling@xxxxxxxxx> wrote: > Considering that my other profession is Geophysicist, I'm kind of up on > those sort of things. The Earth is an oblate spheroid and the computation to > include the curvature of the earth would be a bit more involved. what do you think of the code i mentioned earlier? $distance = number_format(ceil(69*rad2deg(acos(sin(deg2rad($ulat)) * sin(deg2rad($vlat)) + cos(deg2rad($ulat)) * cos(deg2rad($vlat)) * cos(deg2rad($ulong - $vlong)))))); where: $ulat = latitude of user #1 $ulong = longitude of user #1 $vlat = latitude of user #2 $vlong = longitude of user #2 I took the very popular mysql query (at the time) that supposedly works with a sphere and mapped it to php functions and it has appeared to work very well. I have only tested with US zip codes, but the concept should be the same as long as lat/long are centered properly. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
