Hi,
I have a netcdf file with a 3D variable that contains NaN values. These NAN values are written in the form of "" (underscores). All I want is to remove these "underscores" and put 0 instead.
What I have done was to (A) create a cdl file: ncdump BB.nc > BB.cdl
then (B) edit it with vim and substitute "" with zeros: :%s,_,0,*g
and finally (C) recreate the netcdf with ncgen -o BB.nc BB.cdl, but the underscore values persist. :-(
I also used ncap2 command to substitute these values: ncap2 -O -s 'where(EMIS_BB="_") EMIS_BB=0' BB.nc out.nc, but I got an empty variable (EMI_BB).
Hi Nikos,
Your are mixing things up
The underscore in the ncdump indicates that that value is a FillValue (or missing value) Which is currently set to zero ( EMIS_BB:FillValue = 0. ;) If you wish to delete this fill value use the following command.
ncatted -a _FillValue,EMIS_BB,d,d,1.0 bb.nc
( After this you will be able to see all the zero's )
If you wish to change the FillValue to say -1e-6 use the command
ncatted -a _FillValue,EMIS_BB,o,d,1e-6 bb.nc
For a lot of reasons it is a bad idea to have FillValue as zero -So I suggest you change it
...Henry
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Hi,
I have a netcdf file with a 3D variable that contains NaN values. These NAN values are written in the form of "" (underscores). All I want is to remove these "underscores" and put 0 instead.
What I have done was to (A) create a cdl file: ncdump BB.nc > BB.cdl
then (B) edit it with vim and substitute "" with zeros: :%s,_,0,*g
and finally (C) recreate the netcdf with ncgen -o BB.nc BB.cdl, but the underscore values persist. :-(
I also used ncap2 command to substitute these values: ncap2 -O -s 'where(EMIS_BB="_") EMIS_BB=0' BB.nc out.nc, but I got an empty variable (EMI_BB).
If anyone has a better idea, I would appreciate! The netcdf file I am talking about is here: https://www.dropbox.com/s/xcd3unbto0wyvc9/BB.nc?dl=0 .
Thanks in advance!
Hi Nikos,
Your are mixing things up
The underscore in the ncdump indicates that that value is a FillValue (or missing value) Which is currently set to zero ( EMIS_BB:FillValue = 0. ;) If you wish to delete this fill value use the following command.
ncatted -a _FillValue,EMIS_BB,d,d,1.0 bb.nc( After this you will be able to see all the zero's )
If you wish to change the FillValue to say -1e-6 use the command
ncatted -a _FillValue,EMIS_BB,o,d,1e-6 bb.ncFor a lot of reasons it is a bad idea to have FillValue as zero -So I suggest you change it
...Henry
Although long time after, I appreciate for helping me understand what I misunderstood!
Of course, your suggestion worked perfect!
Nikos