how to convert wind direction to degrees?

Hi all, I am working with wind speed and direction but the last is in form of compass, thus it required to convert it to degrees. could anyone kindly help me?

thank you in advance.

[Adam]

What is "form of compass"? Is it a string? A number in some other units?

[Lilya]

It's a direction (N, E, S and W)

Answer 1

[Robert]

You could store the names and values in arrays and look up the angle corresponding to the matching name.

directionValues = 0:22.5:337.5
directionNames = {'N','NNE','NE','ENE','E','ESE','SE','SSE','S','SSW','SW','WSW','W','WNW','NW','NNW'};

directionValues(strcmp(directionNames,'NNW'))

Better yet, put that in an anonymous function

compass2degree = @(dirName) directionValues(strcmp(directionNames,dirName));

compass2degree('ESE')

[Lilya]

Thank you V M :)

Answer 2

[Thorsten]

Set up a list of compass wind directions and corresponding angles in deg:

D = {'N'; 'E'; 'S'; 'W'}; Ddeg = [0; 90; 180; 270];

If you need more compass wind directions, just add them to D and Ddeg.

Create a table with compass wind directions as row names, and one column containing the corresponding angles in deg:

T = table(Ddeg);
T.Properties.RowNames = D;
T.Properties.VariableNames = {'deg'};

So you have

>> T

 T = 

         deg
         ___

    N      0
    E     90
    S    180
    W    270

Now if you have a cell of different compass wind directions

myD = {'N' 'N' 'E' 'W' 'S'}

you can use this array as index into your table to get the corresponding angles in deg:

T(myD,:).deg

 ans =

     0
     0
    90
   270
   180

[Lilya]

I appreciate your help, Thank you :)

Answer 3

[Robert Daly]

Updated answer using the dictionary data type added since R2022b. Intro to dictionaries blog

Dictionaries are vectorised so you can input a cell array of cardinal directions and it will return and array of corresponding wind angles in degrees.

Degrees = [0,0:22.5:337.5]'
Direction = {'','N','NNE','NE','ENE','E','ESE','SE','SSE','S','SSW','SW','WSW','W','WNW','NW','NNW'}';
Cardinal = dictionary(Direction,Degrees)

WindDir = {'NNE','N','SSE','S','SSW','NE','ENE'}
WindDeg = Cardinal(Wind)