First of all - a bit of relief that my difficulty is not in the 'daft' category.

1. Thanks for pointing me to the earlier discussion. I see M's solution and agree that it works fine with two readings - but I can't see an easy way of doing it with an array; say 16 readings? And wind direction needs a good bit of averaging to get a good result.

2. Effect of wind speed. I agree that wind direction is meaningless unless the wind is blowing. I have a threshold that discards direction reading unless there is a reasonable wind speed.

3. Trignometric solution. thanks, a neat idea but how to get the an angle once all the SIN and COS have been summed/differenced? I don't think inverse trig functions are available?

Overall, the task seems so visually simple that I still feel that some addition/subtraction of readings will do the trick. Perhaps it's as simple as:

1. Use, say, the first vector as a reference (zero)
2. Always measuring clockwise, add the angle to the next vector
3. divide by the number of vectors
4. Add this to the first vector
5. Subtract 256 if necssary (i.e one revolution)

The trick is to always measure angles in the same direction, say clockwise?

Regards Bill Legge