Originally Posted by

**dacablegy** I have been using the "Greater Circle Distance Formula" to determine the distance between to points of latitude/longitude (in miles).

**R** = **3963.0 * arccos[sin(lat1/57.2958) * sin(lat2/57.2958) + cos(lat1/57.2958) * cos(lat2/57.2958) * cos(lon2/57.2958 -lon1/57.2958)]**

I now need to calculate a square of '**R**' distnace from center point to tangent of side. I can do this by finding the upper lower left and right bounds to make a square. (i do realize laying this on the globe will give me a pin-cushion, but its close enough)

given what i need to accomplish(and my acceptance of the range of error) i can use the previous formula. But i am not well versed enough in advanced geometery to convert my formula to the 2 states i need it to be in:

1) lat2 = .... (where lon1 = lon2)

2) lon2 = ... (where lat1 = lat1)

any help or better formula to accomplish latitude/longitude ploting given, distance and 1 point would be mush appreciated.

Thanks

Tony