MATLAB: Converting atan2 output to 360 deg

atan2

Hi, I'm using the function atan2, however my output is from -180 to 180 degrees (I converted from radians) How do I modify it such that it outputs a value from 0-360 degrees?

winddir = (atan2(Vi,Ui))*(180/pi);

Best Answer

Since it will be periodic, just add 360 if the value is less than 0. This will suffice to correct the negative angles.

winddir = winddir + (winddir < 0)*360;

You can use atan2d if you prefer to work in degrees, but it will map to the same range, [-180,180], so you will still need to correct for the negative angles.

If you wanted a simple expression that works in one line of code, this should do:

winddir = atan2d(Vi,Ui) + 360*(Vi<0);

Related Solutions

MATLAB: How to convert [-90 90] range of elevation angel in imgradient3 to [0 , 180]

Try this:

Angles180 = @(a) rem(180+a, 360)-90;
Result = Angles180([-90, 0, 90])
Result =
     0    90   180

MATLAB: Direction between points from [0,360]

The function atan2d gives angles that are from -180 to 180. Not a problem. This works:

mod(atan2d(y,x),360)

But you want the angles in a CLOCKWISE orientation? You do understand that is not the standard?

mod(360 - atan2d(y,x),360)

I won't ask why you need them in a clockwise orientation. The angles that come from this second expression are angles relative to a horizontal line, and proceeding CLOCKWISE around the origin.

Note that mod still works even if the angles are not integers. For example:

mod(360 - atan2d(-2,1),360)
ans =
       63.435

So this points at an angle 63 degrees BELOW the right branch of the x-axis.

Best Answer

Related Solutions

MATLAB: How to convert [-90 90] range of elevation angel in imgradient3 to [0 , 180]

MATLAB: Direction between points from [0,360]

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