Re: On cultural differences

[Greg Troxel]

Владимир Калачихин <v.kalachikhin@gmail.com> writes:

> Do I understand correctly that in the English language "wind angle" is
> the angle between the bow of the vessel and the direction from which
> the wind blows?
> And the "wind direction" is the angle between the North and the
> direction from which the wind blows?

I am a native en_US speaker and have read "American Practical Navigator"
by Bowditch, but I have not engaged in boating for years.  My immediate
reaction is that I'm not really sure that those terms mean exactly and
that I'd have to look them up.

I found this, which I can't say is authoritative, but is a clue as to
how English-speaking sailors use the term.

https://www.bwsailing.com/cc/2017/05/calculating-the-true-wind-and-why-it-matters/


> So gpsd always uses "wind angle" and never "wind direction"? Even if
> there is only NMEA0183 MWD sentences?

As I understand it, the MWD sentence has a flag field for "true" vs
"relative".  And thus it can report either the bow/wind angle or the
north/wind angle.  That leaves ambiguous about north being magnetic vs
true.  In the GNSS era, it obviously should be true (now), but in NMEA
heritage, it seems likely that it was magnetic.

It seems consulting the source is in order.


Do you have a device that outputs MWD?  What does it say?  Can you post
samples?