[CF-metadata] CF-1.6 Conformance Requirements/Recommendations

Upendra Dadi upendra.dadi at noaa.gov
Thu Mar 29 10:06:03 MDT 2012


Hi All,
   I am logging in late into this discussion. I am trying to summarize 
where the discussion stands as of now. Please correct me if I am wrong 
with these statements:

  1) Everybody agrees that CF should allow a way of storing geophysical 
variable data even when the geophysical coordinate where the variable is 
measured is missing.
  2) There is no agreement on best way of  doing it (representing the 
geophysical variable data when the geophysical coordinates are missing). 
The current discussion is on whether to allow missing values within 
auxiliary coordinate variables, which CF already does for discrete 
sampling geometries.

Is there an alternative representation for storing missing data if we 
don't allow missing values within auxiliary coordinate variables?

Upendra

On 3/29/2012 11:32 AM, Jonathan Gregory wrote:
> Dear Jim
>
> We are discussing auxiliary coordinate variables. They do not have to be
> 1D or monotonic. Those requirements apply to coordinate variables in the
> Unidata sense. CF distinguishes these two concepts in Sect 1.2.
>
>> The point is, the information in the variable *is* coordinate information,
> I would say, if it's missing, it's not information.
>
>> What if we say something along the lines of, "Applications should treat the
>> data as missing where the auxiliary coordinates are missing when plotting
>> data."?  Would that resolve the problem?
> Plotting is not the only thing that an application might wish to use it for.
> If we said, more generally, "Applications should treat the data as missing for
> all purposes where the aux coord variables are missing", it would be almost
> the same as not allowing missing data in aux coord vars, since there would be
> no point in providing a data value if it was not permitted to use it.
>
> Although I am arguing one side, I could be convinced either way. But it does
> feel unsafe to me at present.
>
> Cheers
>
> Jonathan
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