But then the data is non-compliant, and it sounds like a valid CF
solution is needed.
Two possible solutions come to my mind. The first way would be to store
the undated measurements separately. Record the normal measurements in
the normal way, and then record the undated measurements in a separate
data variable with an index coordinate instead of a time coordinate.
The other way would be not to use time as a coordinate variable at all,
but only as a data variable. Record all the measurements with an index
coordinate instead of a time coordinate. Then define data variables for
year, month, day, and time of measurement, and just fill in what's known
for each one. (It sounds like the month and year are still known even
if the day is not.) This is very similar to the approach taken for
trajectories; see example H.12 in the spec.
Cheers,
--Seth
On 10/25/16 1:31 PM, Dave Allured - NOAA Affiliate wrote:
> Ajay,
>
> I think this is an exception to CF. I recommend using _FillValue or
> missing_value on the time coordinate. Document this in a comment
> attribute on the time coordinate variable.
>
> Also document this somehow in another global attribute that explains you
> made this exception to the CF conventions. Follow CF conventions in all
> other regards.
>
> Then, try to remember to warn people about this when you distribute the
> data. CF compliant time coordinates are fundamental to many application
> programs, and I expect they will choke or introduce subtle errors if
> missing values are in there. So users will need to provide special
> handling for such files. HTH.
>
> --Dave
> (Please reply to list only)
>
>
> On Tue, Oct 25, 2016 at 12:07 PM, Ajay Krishnan - NOAA Affiliate
> <ajay.krishnan at noaa.gov <mailto:ajay.krishnan at noaa.gov>> wrote:
>
> Hi All,
>
> I have a user that's converting some IMMA format files to CF
> compliant NetCDF files.
>
> The problem is that, we've run into several measurements where just
> the hour of measurement has been recorded without the corresponding
> "date". We would prefer not to omit these data in the conversion,
> because they are considered valid measurements (and play a role in
> monthly summary statistics)
>
> How do we represent this in a valid CF NetCDF format since we can't
> use _FillValues for 'time'? Any suggestions for handling such
> special cases?
>
> Thanks,
> Ajay
>
>
>
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>
Received on Tue Oct 25 2016 - 14:26:18 BST
