Project

General

Profile

change unit of code

Added by Ronny Berndt over 11 years ago

Hi,

i have a netcdf file with Kelvin as unit and i want to change it to Celsius.

i used this command to convert:

cdo addc,-273.15 ifile ofile

okay, now i want to change to unit in the parameter table from K to C!
How can i do this? Is there a "chunit" command?

Regards,
Ronny


Replies (10)

RE: change unit of code - Added by Ralf Mueller over 11 years ago

I'm already working on an operator like this. It will be in the next release. As soon it finished it, I will create a new cdo-current release.

ralf

RE: change unit of code - Added by Jaison-Thomas Ambadan over 11 years ago

Hi,

for the time being, you can:

1) ncdump ifile.nc > ofile.dat
2) open the ofile.dat and replace the units to K (manually using a text editor), and save it.
3) ncgen -o new_ifile.nc ofile.dat

Cheers,
J.

RE: change unit of code - Added by Ralf Mueller over 11 years ago

I added a new cdo-current (https://code.zmaw.de/projects/cdo/files) release with setunit and chnuit operators. Please let me know, if they work properly!

regards
ralf

RE: change unit of code - Added by Ronny Berndt over 11 years ago

@Ralf Thehos
Ok, good to know ;-)

@J
Thx, this workaround helped me!

Cheers,
Ronny

RE: change unit of code - Added by Christ Reflin almost 3 years ago

Could you describe to me how to use aforementioned link?

I am new to this, I really appreciate for your help.

MfG,
Christ

RE: change unit of code - Added by Christ Reflin almost 3 years ago

Christian Simanjuntak wrote in RE: change unit of code:

Could you describe to me how to use the aforementioned link?

I am new to this, I really appreciate for your help.

MfG,
Christ

RE: change unit of code - Added by Karin Meier-Fleischer almost 3 years ago

Hi Christian,

this is a really old thread. To change the units of a variable use the setattribute operator.

For example change the units attribute of variable tas to degC :

cdo -setattribute,tas@units=degC infile.nc outfile.nc

-Karin

RE: change unit of code - Added by Christ Reflin almost 3 years ago

Hallo Karin,

thank you for the response,
I obtain this warning

$ cdo -setattribute,tas@units=degC ifile.nc ofile.nc
cdo setattribute (Warning): Variable >tas< not found!

I am using ERA5 netcdf

$cdo partab ifile.nc
&parameter
name=Temperature_Air_2m_Mean_24h
long_name="2 meter air temperature (00-00LT)"
units="K"
datatype=F32
chunktype=lines
/

Could you direct me on this?

Thank you
Christ

RE: change unit of code - Added by Karin Meier-Fleischer almost 3 years ago

This was an example for a variable named tas which is not in your ifile.nc (I don't know the content of your file). You have to change tas to the name of your variable (Temperature_Air_2m_Mean_24h ?). Do you want to set the units attribute to degC then it should be ok.

RE: change unit of code - Added by Christ Reflin almost 3 years ago

Thank you I found the solution by replacing "the variable"

tas@units to Temperature_Air_2m_Mean_24h@units

Thank you
Christ

    (1-10/10)