hi
I have 11 netcdf files, each of 5 years durations for a particular search constraint.
1951-1955,
1956,1960,
1961-1965
and so on till 2005
now I want to combine all these files to make one single file starting from 1951 and ending at 2005
anyone can plz help me what nco command should I use?
Hi Summera,
You can use the "ncrcat" command. The command requires the names of the individual files (you can also use wildcards to reduce writing) followed by the name of the output file. In your case, it could be expliciting each of the files, like:
$ ncrcat 1951-1955.nc 1956-1960.nc ....... 1996-2000.nc 2001-2005.nc output.nc
In which case the file "output.nc" will have all the 11 files together, with the time flowing smoothly from 1951 to 2005.
If your file names start with the same characters, for example
* t2m_1951-1955.nc
* t2m_1956-1960.nc
... and so on
Then the writing can be simplified using wildcars and simply become:
$ ncrcat t2m* output.nc
Which will automatically take all the files starting with "t2m" and smartly join them, in ascending time order as you are needing.
Hope it helps.
Cheers,
Ramiro
Hi Summera Khan and Ramiro Saurral,
A Python package called "xarray" will accomplish your task in less than 10 seconds. It is particularly tailored to working with netCDF files. Hope it helps
Best,
Salah
Ramiro Saurral "ncrcat" gives following error
'ncrcat' is not recognized as internal or external command, operable program or batch file.
Salah Basem Ajjur if you can further explain...i m new to nco
Do you have nco installed in your computer? When installed, it brings ncrcat within the nco package, so doing this should be pretty straightforward.
More info here:
http://nco.sourceforge.net/nco.html#ncrcat-netCDF-Record-Concatenator
i have nco-4.9.5.windows.mvs installed on my computer.
i m using windows 10
Hi Summera,
Ramiro advised you to use the "ncrcat" command in NCO. NCO is a good netCDF operator, however I am not using it to merge netCDF files. I found the "xarray" package more efficient and faster. This does not mean you don't have to learn the NCO way. You will mostly need it if you're dealing with netCDF files.
The "xarray" is an open-source Python package (i.e., without using NCO). It integrates tightly with a flexible library called "dask" for parallel computing in Python, making it faster to merge netCDF files. You should first install the needed packages like dask, xarray, and netCDF4. Then, a simple code will allow you to pick any single file and merge all in that folder into a new file. Remember, your wildcard should cover all files in that folder.
Please read more about the NCO way from Ramiro reference, about "xarray" from http://xarray.pydata.org/en/stable/, and about "dask" from https://docs.dask.org/en/latest/.
You will also find a GitHub discussion on xarray at https://github.com/pydata/xarray/discussions and a StackOverflow on https://stackoverflow.com/questions/tagged/python-xarray.
Best wishes,
Salah
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