Download NetCDF data via command window
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How do I download NetCDF data through my 'comand window' from my matlab?
Website with the data below:
Accepted Answer
Mathieu NOE
on 17 Oct 2022
hello (again) Augusto
try this code.
The results are saved in one single excel file (attached FYI), each year on a new sheet. Of course you can change that logic and save each results separately in a specific file
hope it helps
% Download the CPC data used in the script below
year_start = 1990; % first year to download
year_stop = 2019; % last year to download
nb_of_years = year_stop - year_start +1;
httpsUrl = "https://psl.noaa.gov/thredds/fileServer/Datasets/cpc_global_precip/";
filename_tmp="temp.nc"; % temporary filename (for loop); data will be always stored under this temp name
LG=[-48.25 -48.75 -49.25] + 360; % longitude (NB range is 0 : 360°)
LT=[-1.25 -1.25 -1.25]; % latitude
% export results to excel
filename_export='PRP_CPC.xlsx';
%% main loop
for ci = 1:nb_of_years
clear Precip
filename = strcat("precip.", num2str(year_start+ci-1), ".nc"); % create filename according to list above
disp(strcat(filename, " is processed"));
dataUrl = strcat(httpsUrl, filename);
data = webread(dataUrl);
filename_out = websave(filename_tmp,dataUrl); % save downloaded data
% ncdisp(filename_tmp,'/','min'); % commented, just to avoid filling the command window
precip=ncread(filename_tmp,'precip'); % Dimensions: lon,lat,time
long=ncread(filename_tmp,'lon');
lat=ncread(filename_tmp,'lat');
time=ncread(filename_tmp,'time');
for i=1:3
LGG=find(long==LG(i));
LTT=find(lat==LT(i));
if isempty(LGG)||isempty(LTT)
disp('LOCATION NOT FOUND IN THIS NetCDF FILE')
break
end
% Step 5 :Convert 3 dimensional array to column vector array for one station
Precip(:,i)=precip(LGG,LTT,:); % Unrecognized function or variable 'precip'.
X(i)={'Precipitation(mm/day)'};% label for variable
end
latt2=[LG ; LT];
time=double(time);
AA=time/24+datenum('1900-01-01 00:00:0.0');
[yy,mm,dd,~,~,~] = datevec(AA);
date1=[yy mm dd];
DD={'Year','Month','Day'};
sheet=ci; % NB : every year on a new sheet - same file
C={'LOCATION: Cities','','','Longitude';'DATE FROM JAN-DEZ 2021','','','Latitude'};
writecell(C,filename_export,"Sheet",sheet,"Range",'A1');
writecell(DD,filename_export,"Sheet",sheet,"Range",'A3');
writematrix(latt2,filename_export,"Sheet",sheet,"Range",'E1');
writecell(X,filename_export,"Sheet",sheet,"Range",'E3');
writematrix(date1,filename_export,"Sheet",sheet,"Range",'A4');
writematrix(Precip,filename_export,"Sheet",sheet,"Range",'E4');
end
5 Comments
Augusto Gabriel da Costa Pereira
on 18 Oct 2022
Mathieu NOE
on 18 Oct 2022
ok
glad if I can help !
Augusto Gabriel da Costa Pereira
on 18 Oct 2022
Mathieu NOE
on 19 Oct 2022
hello
I don't think there is a problem with the code itself as I tested it sevaral times without an inch
maybe your internet connection had a glitch that caused matlab to fail during the data loading
Walter Roberson
on 19 Oct 2022
- your system might have interrupted the connection, such as if you ran out of system memory or operating system resources
- your system security software or local network security might have terminated the connection for various reasons such as mistaken belief that the data holds a virus
- your network service provider might have terminated the connection because it believes that you have used more total data than you contracted for
- your network service provider might have terminated the connection as a way of rate-limiting the connection
- there might be a network glitch or network overload somewhere on the path that resulted in the connection being terminated. With that particular transmission technology, a single corrupted packet would not lead to that: if the corruption was noticed then the protocol would end up asking for retransmission. But if someone dug up the network cable with a backhoe then the connection is going to fail
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