Date: Sun, 04 Jan 1998 10:05:51 -0600

From: Ben Heath

I've found a program that will compute the distance between 2 points latitude and longitude. The comments say it uses the Law of Cosines. I've been trying to prove the formula used, but seem to get stuck when going to three space. Here's the formula used:

distance = R*cos(cos(lat2)cos(lat1) + sin(lat1)sin(lat2)cos(long1-long2))

It's a fun little problem that may give some students a purpose for using trigonometry.