Derived Data True Wind Angle
In the derived data plugin, why does TWA require navigation.headingTrue?
TWA should be relative to the bow, like AWA, and can be calculated from apparent wind and STW.
8 Replies
it outputs true wind direction as well
You need heading to calculate TWA
Think about it…
he is right, TWA should just need AWA and STW, it is TWD which is also part of that calc that needs it - True wind Direction is relative to true heading where as TWA is relative to the boat
actually TWA needs AWA, STW and AWS (sorry I missed AWS)
Yeah, it’s for TWD
We should break that into a separate calculation
@barnaclebill do you have navigation.headingMagnetic? do you have a compass? if so in Derived Data turn on Magnetic variation and you will get navigation.headingTrue
The problem is in the code. It calculates TWD and TWA, but it gives up if there is no compass direction. I modified it and will test and submit a PR if the fix works.
or just write your own custom calc
https://github.com/SignalK/signalk-derived-data/tree/master
"To add new calculations, just create a new file under the ./calcs directory."
No. This is a good change.