Calculate Direction from U,V

It sounds to me like a basic "how to convert rectangular to polar coordinates" type problem. (basic tutorial with a calculator here http://www.analyzemath.com/Calculators/Rect_Polar.html).

You are correct that this usually involves the arctan function (=ATAN() and ATAN2() functions in Excel see help file here http://office.microsoft.com/en-us/ex...in=HP010342680). When you say you " haven't had any success." in what specific ways has it failed? Have you gotten error values back? Incorrect values? Excel's trig functions operate on angles in radians, are you looking for results in degrees and did not realize that Excel used radians? Perhaps if you can explain to us what you have done that has not worked, we can better help.

On edit: Another thing to consider - by convention, the arctan function usually returns angles in the 1st and 4th quadrant (-pi/2 to +pi/2). Your directions can probably cover the entire circle, so you may need an additional step in the algorithm if the desired angle is in the 2nd and 3rd quadrants.