How can i calculate mean wind direction(in degrees) from 1 minute to 10 minutes?

Hi everybody, i have a problem, i have a 1 min data of the wind direction(in degrees) of 3 months, but i want the average every 10 minutes of this data.

I have the matlab 2015, so .. i can't use circ.mean.

Can you help me with that, please?

Thank you in advance

Best!!!

[Walter Roberson]

What is "circ.mean" ?

What form is the time information in? Or is it safe to assume that the data definitely starts on an even 10 minute boundary and is definitely every 1 minute?

[Ana Soph]

hi, thanks for answering, about your questions...

1. circ_mean is Mean direction of a sample of circular data (this is what i need)
2. Yes, is safe to assume that the data definitely starts on an even 10 minute boundary and is definitely every 1 minute

i am waiting your answer, thanks (:

Answer 1

[Ana Soph]

The final script is:

M = xlsread('Dic2019','Dic2019mat')
ten_minute_avarege = meanangle(reshape(M, 10, []), 'omitnan')
A = ten_minute_avarege';
for i=1:length(A) 
    if A(i)<0, A(i)=A(i)+360; end
end
A = A(:,1);
A = reshape(A,144,length(A)/144);
xlswrite('datosexcel1.xlsx', A', 'Hoja1', 'A1')

thanks all! :D

[Walter Roberson]

? I was not able to find any meanangle() function that access 'omitnan' as an option?

[Ana Soph]

https://au.mathworks.com/matlabcentral/fileexchange/12631-mean-angle i use this, with the solution of path that you give me, thanks a lot

[Walter Roberson]

I see. Hacking based on the fact that the code does not check whether the dimension number it is passed is reasonable.

[Ana Soph]

So.. This is not ok?

[Walter Roberson]

It looks like it will work. It might confuse readers, so I recommend commenting it why it works.

[Ana Soph]

Ok ok, i understand, the reason that i think it works is because i use values that i now the answer and use the program. So, i validate random intervals of numbers too, but i don't sure that is enough, i am very new in matlab

[Walter Roberson]

It should work with numeric values, including values that might include nan.

It just is not an intended way of calling meanangle. But it will work because meanangle was sloppy in not checking that the parameters were what the function expected.

[Ana Soph]

oh.. ok, i understand

Answer 2

[Walter Roberson]

If you can be sure that the data starts on a 10-minute boundary and that there is no missing data, then

ten_minute_avarege = mean(reshape(WindData, 10, []), 'omitnan')

If you are sure you have no nan entries, then you can leave out the 'omitnan'

[Ana Soph]

but the data is in degrees... i need the mean of a set of angles (in degrees) based on polar considerations.

[Walter Roberson]

You can use https://www.mathworks.com/matlabcentral/fileexchange/10676-circular-statistics-toolbox-directional-statistics circ_mean() but make sure to convert your angles to radians first.

[Ana Soph]

yes, is true, but i have matlab 2015, and can't use in this matlab that function :c

[Walter Roberson]

What error message do you get when you try to use the function?

[Walter Roberson]

I just tried in R2015a and had no problem using the circ_mean function from that File Exchange Contribution.

[Ana Soph]

really? omg!; i have this error: Undefined function or variable 'circ_mean'.

this is my code

M = xlsread('Dic2019','Dic2019mat')
ten_minute_avarege = circ_mean(reshape(M, 10, []), 'omitnan')
xlswrite('datosexcel1.xlsx', ten_minute_avarege, 'Hoja1', 'A1');

[Walter Roberson]

You have to download the code from the File Exchange, and unzip it into its own directory that is not under the MATLAB installation directory. Then use pathtool to add that directory to the path, and save.

[Ana Soph]

THANK YOUUUUUU <3