how can I calculate the nautical direction angle from Cartesian x- and y-component of velocity

10 views (last 30 days)
I have a set of Cartesian x- (u) and y-component (v) of velocity. But I want the velocity to be Nautical direction based, which I did the follows:
for k=1:length(u)
if u(k) > 0 && v(k) >0 % velocity direction is from southwest and pointing towards northeast
dir(k) = 180+rad2deg(atan(abs(u(k))./abs(v(k))));
elseif u(k) < 0 && v(k) >0
dir(k) = 180-rad2deg(atan(abs(u(k))./abs(v(k))));
elseif u(k) < 0 && v(k) <0
dir(k) = rad2deg(atan(abs(u(k))./abs(v(k))));
dir(k) = 360-rad2deg(atan(abs(u(k))./abs(v(k))));
May I know if my understanding is conceptually correct?
jie hu
jie hu on 27 Dec 2023
Moved: Dyuman Joshi on 27 Dec 2023
thanks, But I am talking about the direction in Nautical convention. for y1 = atan2d(10, 10) = 45, shall that angle be 225 in Nautical convention?
Dyuman Joshi
Dyuman Joshi on 27 Dec 2023
As I said earlier, I am not familiar with Nautical convention.
Could you provide a definition/reference to it?

Sign in to comment.

Answers (1)

Chunru on 27 Dec 2023
Edited: Chunru on 27 Dec 2023
vx = 10;
vy = 10;
v = sqrt(vx.^2 + vy.^2)
v = 14.1421
theta = wrapTo360(90 - rad2deg(atan2(vy, vx))) % Earth coordinates, with ref to North, Clock wise
theta = 45
Chunru on 27 Dec 2023
In nautical navigation the absolute bearing is the clockwise angle between north and an object observed from the vessel.
The wind direction is defined as the direction from which the wind originates (the opposite of the wind velocity vector).

Sign in to comment.


Find more on Earth, Ocean, and Atmospheric Sciences in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!