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Re: Exporting to netCDF

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  • Subject: Re: Exporting to netCDF
  • Date: Thu, 28 Apr 2005 10:49:47 -0600
Hi Noman,

> Per your suggestions we are now letting user specify units in all
> export tools and writing them in the netCDF file.  But we also want
> to let users write a netCDF file without units in case they don't
> know the units. My thought is - no unit is better than incorrect
> unit.
> 
> There is no problem when we know the unit. 
> 
> However, it seems like we are having problem when we don't specify
> the unit of a variable. We can still create the file but the values
> (data) in the netCDF file are incorrect (garbage).
> 
> Are we using incorrect method or something while specifying a
> variable and writing to a netCDF file? Is there any way we can write
> a variable without specifying units if necessary?

There should be no problem writing a variable without specifying a
units attribute.  The units attribute is only a convention and is not
treated in any special way by the netCDF library, it just treats it
like any other attribute.

There are times when no units attribute is meaningful, for example if
a variable just refers to an index, as in the "lastReport" variable of
the Station Data described in

  
http://www.unidata.ucar.edu/packages/netcdf-java/formats/StationDataFormat.html

Lots of people write netCDF variables without units and read the data
in OK.

Do you have a small example writing a variable without a unit that
fails?  If so, please send it and we'll try to figure out what is
going wrong.

--Russ