Hi Adriana,
> Hello Support,
> I'm wondering if you can help me with two questions related to creating
> NetCDFs. The first has to do with unit names. I'm creating a file of water
> isotopic data, the standard unit for which is "permil" or parts per
> thousand. Neither "permil" or "parts per thousand" are acceptable according
> to the CF Conventions checker, which uses the Unidata udunits library.
> However, from a scientific perspective, reporting the isotope ratios in
> "percent" or another such unit does not make sense. Do you have any
> recommendations?
In the âUnitsâ section of the CF Conventions document, the 3rd paragraph
discusses percent, ppm, etc. I believe it indicates you should use â1e-3â
for units and further details can be included in the âlong_nameâ attribute
(or âstandard_nameâ attribute, if appropriate).
> The other question is about flag_values. Would you be able to help me
> understand how to write flag_values so that I do not encounter the
> following error: "ERROR: Attribute flag_values of incorrect type (expecting
> 'Data Variable' type...)" I receive this error message whether I write the
> flag_values as a string, an integer, or a double. My flag values are 0 and
> 1.
The CF âFlagsâ Section says that the flag_value has to match the data type
of the data variable. The flag_meaning is a blank separated string that
provides the meaning of the flag/data values. Flag variables are most commonly
stored as bytes. The first example in the âFlagsâ section provides a CDL
snippet of a flag variable provides a nice example:
byte current_speed_qc(time, depth, lat, lon) ;
current_speed_qc:long_name = "Current Speed Quality" ;
current_speed_qc:standard_name = "status_flag" ;
current_speed_qc:_FillValue = -128b ;
current_speed_qc:valid_range = 0b, 2b ;
current_speed_qc:flag_values = 0b, 1b, 2b ;
current_speed_qc:flag_meanings = "quality_good sensor_nonfunctional
outside_valid_range" ;
> Thank you in advance for your help,
> Adriana
Hope that helps.
Also, for CF focused questions like these, the best place to ask for help is
the CF Discussion forum (also see the CF Discussion page). There are more CF
experts there than we have here in the netCDF group.
Cheers,
Ethan
Ticket Details
===================
Ticket ID: PCM-734975
Department: Support netCDF
Priority: Normal
Status: Open
===================
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