How to combine the data from multiple netcdf files and make it one .mat file?

Question

Pankaj R. Kaushik 2023-2-22

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https://ww2.mathworks.cn/matlabcentral/answers/1916725-how-to-combine-the-data-from-multiple-netcdf-files-and-make-it-one-mat-file

编辑： Stephen23 2023-2-22

I have 100 years of rainfall data (100 netcdf file for each year) and one netcdf file contains one year rainfall data in months.

So the data format is like for one year netcdf file: lon*lat*12 %here time is 12 months

In the 100 years of netcdf file data, I need to get 1200 months data.

However, When I am using this loop to store the rainfall data, the loop didn't run for the entire 100 netcdf files. It just store the first netcdf file data.

I need to get the data like lon*lat*1200 (months)

%% List of files
list_of_files= dir(fullfile(ddir,'*.nc'))
%% Read Rainfall Data
for i=1:length(list_of_files);
    filename = fullfile(ddir, list_of_files(i).name);
    R = ncread(filename,'monthly_rain');
    Rainfall (:,:,i) = R; 
end

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Answer 1

KSSV 2023-2-22

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https://ww2.mathworks.cn/matlabcentral/answers/1916725-how-to-combine-the-data-from-multiple-netcdf-files-and-make-it-one-mat-file#answer_1177120

在 MATLAB Online 中打开

%% List of files
list_of_files= dir(fullfile(ddir,'*.nc'))
%% Read Rainfall Data
filename = fullfile(ddir, list_of_files(1).name);
% Read lon 
lon = ncread(filename,'lon') ;
nx = length(lon) ; 
% Read lat 
lat = ncread(filename,'lat') ;
ny = length(lat) ;
% 
nt = length(list_of_files) ; 
Rainfall = []; 
for i=1:nt
    filename = fullfile(ddir, list_of_files(i).name);
    R = ncread(filename,'monthly_rain');
    Rainfall = cat(3,Rainfall,R) ;
end

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Pankaj R. Kaushik 2023-2-22

Many Thanks, It worked!

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Answer 2

Stephen23 2023-2-22

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1916725-how-to-combine-the-data-from-multiple-netcdf-files-and-make-it-one-mat-file#answer_1177140

编辑：Stephen23 2023-2-22

在 MATLAB Online 中打开

Do not expand/concatenate the data inside the loop!

A more robust & efficient approach: concatenate once after the loop:

S = dir(fullfile(ddir,'*.nc'));
S = natsortfiles(S); % you might need this to get the correct file order
for k = 1:numel(S)
    F = fullfile(ddir,S(k).name);
    R = ncread(F,'monthly_rain');
    S(k).data = R;
end
A = cat(3,S.data)