RE: [PHP] lat lon function

Basic geometry. More appropriately triangulation. The figure that you describe is a right triangle. Horizontal & vertical components are 1 unit long. The diagonal would be the square root of 2. The distance is equal to the sqrt(2) * 69 miles (length of one leg). That distance can be somewhat misleading though because most likely you would not be traveling in a straight line. Over long distances it is even less accurate because of the curvature of the planet. Bryan -----Original Message----- From: Edward Peloke [mailto:epeloke@echoman.com] Sent: Tuesday, April 08, 2003 10:36 AM To: Php-General@Lists. Php. Net Subject: RE: [PHP] lat lon function Don, How would I get distance? If my search is for a place with a lat of 30 and long of 87 and I see a place with a lat of 31 and long of 88, how do you get the rough distance? Thanks, Eddie -----Original Message----- From: Don Read [mailto:dread@texas.net] Sent: Tuesday, April 08, 2003 12:51 PM To: Edward Peloke Cc: Php-General@Lists. Php. Net Subject: RE: [PHP] lat lon function On 08-Apr-2003 Edward Peloke wrote: > Thanks, I will start to play with this, has anyone here done a query > like this? > You could bracket the set of *possible* airports by : SELECT ... FROM ... WHERE lat BETWEEN latmin and latmax AND lon BETWEEN lonmin and lonmax The min/max values being calculated as 69 miles per degree from the origin airport. <snip> Regards, -- Don Read dread@texas.net -- It's always darkest before the dawn. So if you are going to steal the neighbor's newspaper, that's the time to do it. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php