How to get True Wind Direction instead of apparent using Signal K.

[dreeas]

Ah, I see. I googled and found the formula for conversion but no clue how to do that in the query in Grafana.
Is there no setting or tweak in Signal K to output degrees?

Signalk works with SI units, it's down to whatever is displaying the data to do any unit conversions. 
In Grafana there's a math function in Select >>

I did this by multiplying by 57.295 but that will only be correct with wind from 0-180 degrees wont it?
I have installed the "Derived data" and tested by selecting most of the options under "Wind" but I do not get any new data points under data browser. Is there anything else needed to get calculated data from this addon?