Average for 4d data

Hi! How can I calculate the average for a 160x140x1x12 which are lat,lon,year and month. I want to calculate the average of month for one year.

Answer 1

[Ameer Hamza]

You can specify the dimension to the mean() function

M = rand(160,140,1,12);
M_new = mean(M, 4)

[Nurul Ain Basirah Zakaria]

hi, can i ask. why when i plot a year, for 12 months, the output for y axis is 0-7 and x-axis is 20-105 but if i calculate the average and then i plot, both x and y axis is 20-140 and 20-160. But, y-axis should be 0-7 because of my latitude.

[Ameer Hamza]

How are you plotting the two figures? What is the command? Most probably, you are not passing the X and Y matrix in the second case.

[Nurul Ain Basirah Zakaria]

The first one i use:

[m,n,p,o]=size(E);

>> for i=1:o

pcolor(lon,lat,E(:,:,:,i));

shading interp

colorbar

drawnow

end

and the size of E is 160 140 1 12. the outcome is like the first figure

but when i average/mean for the months(12);

size of new E is 160 and 140.

so i just pcolor(newfile), and the outcome is like the second figure above.

[Ameer Hamza]

You also need to pass lon, lat in the 2nd call to pcolor too

pcolor(lon,lat,newfile)

[Nurul Ain Basirah Zakaria]

sir, thank you very much. excuse me for my slow brain.

[Ameer Hamza]

I am glad to be of help! :)