Best tool for analysing/altering netcdf data (beyond read-only)
2 vues (au cours des 30 derniers jours)
I have a large netcdf file that I would like to do some processing on. CDO software is not adequate enough and I need to resort to using matlab. I can access the data easily with the 'ncread' commands etc but I would like to know how to apply an analysis (say, an equation using a few varibles of the dataset) on the netcdf file using matlab. For instance, can I use matlab to create a new variable in the netcdf file? I have seen the NCToolBox add on for Matlab but this is read-only.
I have a netcdf file with about 10 climate variables and I would like to implement a scheme to calculate a new variable directly within the netcdf. I can use ncread to read in the data but then I am not too sure how I keep other attributes such as time when performing the calculations. My scheme will involve a few steps as well as boolean analysis, so I am a bit confused there.
Hope I explained that well enough,
Ashish Uthama le 17 Juin 2015
There are more functions in the ncread family - Have a look at all of them here.
Look at ncwrite for write capability, the documentation has some examples to help you get started.
Once you get the data into MATLAB using ncread, then you can leverage any of MATLAB's analysis functionality on it (its just numbers to MATLAB at this point).
Chad Greene le 17 Juin 2015
I'm not sure what the problem is. NetCDF files contain matrices, which are well suited for Matlab (MatrixLaboratory). To get a variable like sea surface temperature,
sst = ncread('myfile.nc','sst');
Then you can do whatever analysis you want on the sst matrix. After you've used ncread the analysis part of your question has nothing to do with the fact that the matrix originally came from a NetCDF file. When you're satisfied with your analysis, use ncwrite to write a NetCDF file with whatever variables you'd like.
hafez ahmad le 16 Jan 2020
I did in the following way.
ncid1 = netcdf.open(NETCDF_File1,'NC_NOWRITE');