NetCDF File Assign Variable Loop from Array
4 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Mark Nakers
am 23 Apr. 2020
Bearbeitet: per isakson
am 24 Apr. 2020
I have a row vector that consists of 13 heights (in meters):
z = [1.5,3,4.5,6,7.5,9,10,11,12.5,14,18,23,29];
I'm attempting to retreive data from a NetCDF (.nc) file, which has "built in" variables.
Each height has two variables, assocaited with it: u and v, each of which are a 60x14400 double. (The first dimension is the
sampling frequency (60 Hz). The second dimension is time in seconds since an initial start time.)
For example, to load 1.5m u and v and assign to variables "1_5u" and "1_5v" I would do:
1_5u = ncread(FilePath,'u_1_5m_vt');
1_5v = ncread(FilePath,'v_1_5m_vt');
For 10m u and v, I would do
10u = ncread(FilePath,'u_10m_vt');
10v = ncread(FilePath,'v_10m_vt');
And so on.
However, my main goal/question is: How could I create a loop to reference each height in z and load each variable?
Here's how I started:
for i = z
j = mod(i,1);
if j == .5
fNameu = ['u_' num2str(fix(i)) '_5m_vt'];
fNamev = ['v_' num2str(fix(i)) '_5m_vt'];
? = ncread('../data/isff_20070403_20.nc',fNameu);
? = ncread('../data/isff_20070403_20.nc',fNamev);
else
fNameu = ['u_' num2str(i) 'm_vt'];
fNamev = ['v_' num2str(i) 'm_vt'];
? = ncread('../data/isff_20070403_20.nc',fNameu);
? = ncread('../data/isff_20070403_20.nc',fNamev);
end
end
I have three questions here:
1) How can I assign two variables to each height with unique variable names for each? (Getting 26 variables in total)
2) How do I account for the fact some elements in z have a decimal, but the var name in the file is an underscore? (It is also important to keep the 'z' array as I'm referencing it in other locations)
3) How could I then take each of these variables and create 26 additional variables WITHIN THIS LOOP to take the mean of each variable over the first dimension (i.e. average over the first dimension of 60 frequencies) over a specific time period (the second dimension)
For example for 1.5m, something like:
uMean1_5 = mean(u_1_5(timeRef),1);
vMean1_5 = mean(v_1_5(timeRef),1);
How can I also include this within the loop?
2 Kommentare
per isakson
am 24 Apr. 2020
I doubt it is a good idea to create that many variables. See TUTORIAL: Why Variables Should Not Be Named Dynamically (eval)
The first character of a variable name must be an English letter. 10u is not legal.
Akzeptierte Antwort
per isakson
am 24 Apr. 2020
Bearbeitet: per isakson
am 24 Apr. 2020
Partial answer. Replace
? = ncread('../data/isff_20070403_20.nc',fNameu);
by
assign( txt, ncread('../data/isff_20070403_20.nc',fNameu) )
where the value of txt is the name of the variable to be created
and where
function assign( Name, Value )
% assign assigns the value of Value to a variable named Name
%
% Example:
% assign( 'M', magic(5) )
% for k = 1:11, assign( sprintf( 'var%d', k ), k ), end
narginchk( 2, 2 )
assert( isvarname(Name), 'assign:IllegalName' ...
, 'First input argument, "%s", must be a legal name', Name )
assignin( 'caller', Name, Value );
end
0 Kommentare
Weitere Antworten (0)
Siehe auch
Kategorien
Mehr zu NetCDF finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!