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AxsDeny · Joined: 30 Sep 2005 Posts: 1

I'm trying to retrieve coords that fall on the perimeter of a circle that is 50 miles in radius from a central coordinate set. Using the great circle method I'm able to determine distance from the central point.

Anyone have some PHP code that would accomplishg determining such an array? I would say that a point at every 1 degree of rotation would be enough points.

I've been able to brute force it by creating an array of all possible coords in the area then using great circle to find those that fall on a 50 mile distance. But that is less than ideal for my sanity (and my processor power.)

Help appreciated. Wink

Scout · Joined: 16 Sep 2003 Posts: 235

What you want to do is project a waypoint, given the center of your circle and your radius.

Divide 360 by the number of waypoints you want on your circle, then project a new waypoint for each step around the circle, keeping the center and radius the same.

An online resource that can project a waypoint for you can be found at http://williams.best.vwh.net/gccalc.htm
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Scout http://GPSgames.org