Display a degree heading as a compass heading rather than a absolute heading from the origin.

title(sprintf('HMNZS AOTEAROA Ship motion in Sea state 6,\n Heading: %3.2f%c     Runtime:%4.2f sec'...
            , d , char(176), t), "Color", [1 1 1]);                        % Display Graph title with changeing data  

I am wanting to display the heading of the vessel in a compass format. Currently, as it goes around in a circle the heading goes up to 758 degrees I believe there is a way to make it only display a heading from 0 to 359 deg.

I think it goes like this

 C = Heading / 360
 H = ??? % truncate CH to only leave digits after the decimal point 
 CH = H*360

Not sure how to truncate the whole numbers.

Thanks in advance

[Strahan Kelly]

I believe I found the answer the function I was after is rem(a,b).

CH= rem(Heading,360)   % This will give me the remainder of the degrees 
% that are not part of a complete loop/ circle

So if Heading =760

Ch = 40

[Adam Danz]

mod is better than rem for reasons explained in my answer below. Also, you should decide what should happen when Heading is 360: should it convert to 0 or stay at 360? That's also explained in my answer.

Answer 1

[Adam Danz]

See wrapTo360() from the Mapping Toolbox.

Otherwise,

Use mod() to wrap a value to [0,360] rather than rem()

theta = 758;
wrapped = mod(theta, 360);

Examples

mod(540, 360)

ans = 180

mod(-90, 360)

ans = 270

mod(360,360)    % Note: returns 0

ans = 0

mod(360*2, 360) % Note: Returns 0

ans = 0

To keep 360 from changing to 0,

theta = 360; 
mod(0, 360) + 360*(mod(theta, 360)==0 && theta>0)

ans = 360

theta = 360*2

theta = 720

mod(0, 360) + 360*(mod(theta, 360)==0 && theta>0)

ans = 360

Look what happens when you use rem

rem(-90,360) % oops!

ans = -90