Re: Add DATE in an exsisting NC file

Hello Dave, 

thank you very much for the helping reply. It is quite clear and I will follow 
your instructions. I am new in netcdf but it seems quite straight forward to 
program

All the best

Simone


On Thursday 17 May 2007 23:13, Dave Allured wrote:
> Simone,
>
> It is unclear what you are asking.  If you want to write a single
> date into a Netcdf file, then I suggest writing a global string
> attribute named "date" with a value of, for example, "2007-May-17"
> or "2007-05-17".  (First form preferred to prevent ambiguity.
> Always use four digit years.)
>
> If your file contains a time series, and you want to add a list of
> dates to identify the time steps, then I strongly recommend that you
> add a numeric time coordinate variable that uses Udunits time
> encoding, and follows certain Netcdf standard conventions:
>
> http://www.unidata.ucar.edu/software/udunits/
> http://www.unidata.ucar.edu/software/netcdf/conventions.html
>
> I use parts of the COARDS and CF conventions for time coordinates,
> with good compatibility for graphics software such as Grads and NCL.
>
> For a brief introduction, see the paragraphs on coordinate systems
> and calendar in the Best Practices document:
>
> http://www.unidata.ucar.edu/software/netcdf/docs/BestPractices.html
>
> Here are my minimum recommendations to make a simple time coordinate
> variable:
>
> Add a time coordinate array that is type double and one dimensional.
>   DO NOT use a string array.
>
> Name of time dimension = time
> Name of time coordinate variable = time
>
> Minimum attributes:
> * units = "days since 1800-1-1 0:0:0"
> * calendar = "gregorian"
> * long_name = "Time"
>
> It is good to also include the optional actual_range attribute, a
> type double array of dimension (2), containing the first and last
> values from the time coordinate variable.
>
> This is a basic prototype for you.  There are complexities regarding
>   the data type and attributes that I will not go into unless
> needed.  I hope this gets you started.
>
> --Dave A.
> CU/CIRES Climate Diagnostics Center (CDC)
> NOAA/ESRL/PSD, Climate Analysis Branch (CAB)
>
> Simone Marras wrote:
> > Good morning, I am dealing with a set of *.nc files which do not contain
> > any date nor information on the time and, for what I need to do with
> > those files, I actually need to add the DATE as YY-MM-DD in the files.
> >
> > Has anyone ever gone through this?
> >
> > I hope someone can help me with this
> >
> > Thank you in advance,
> >
> > Regards
> >
> > Simone
>
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-- 
Simone Marras, Ph.D. Student
BSC & Universitat Politecnica de Catalunya
Jordi Jirona 29
08034 Barcelona
Spain

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