Excellent - drove me to distraction!

I've looked through a few of the answers and noticed that most people have used their own implementation to derive the lowest common denominator which ultimately uses a calc to generate the "greatest coomon divisor". I used the BigInteger class for this - which gives you "gcd()" for free. Is there a reason that the previous 174 people haven't used it? Performance maybe?

Would love to know as my Java experience is limited - so am trying to utilise/learn as much as possible.

agh! Finally finished this - my answer works, though verbose.
My only observation is that failng tests require should state as a minimum what the expected value is.

Fantastic learning exercise though.

Am getting

testSingle(SimplexerTest)
expected: but was:

Any help here? I have no idea what condition I am failing. All cases of a single 'token' have been covered?

The following needs explaining:
"If the rounded headwind component is 0, "Head" should be used. Similarly, "right" in case crosswind component is 0."
As a pilot, if I calculate a headwind/tailwind component as zero, I am in a situation where I have a "pure" crosswind (i.e. 90 degrees from left or right.) Similarly a crosswind component of zero can only be directly ahead or behind me. For a reasonable proof check out the calculator at: http://www.aeroplanner.com/calculators/avcalcdrift.cfm

The kata tests need changing to either define more correctly the method to be used, or take the above into consideration.

Nice idea for a problem; poor implementation though. Dissapointed.

Remove the "static" from the test
This too should be fixed

I agree...
It is entirely feasible that the result of squaring the digits in the source exceeds Integer.MAX_VALUE - this should have been a test case.