[CF-metadata] scalar coordinates

From: Kettleborough, Jamie <jamie.kettleborough>
Date: Fri, 24 May 2013 11:34:54 +0000

Hello Mark,

I'm not sure I understand your example:
>
> For example a data creator may have a set of descriptors and
> identifiers which define how a particular data set is defined
> with respect to a larger study, such as a multi-model
> analysis meta-experiment. Each data set is produced by a
> model with a collection of scalar coordinates from that model
> run, e.g. 'ensemble member number', 'experiment id',
> 'perturbation scheme', 'forcing parameter a', forcing
> parameter b', ... etc.
>

For instance I *think* this can be encoded without the use of scalar coordinates as something like:

dimensions:
       ensemble_member_number = 1;
       strlen = 64;
variables:
       int ensemble_member_number(ensemble_member_number);
           :
       float tas(realization); // example data
           :
       char experiment_id(ensemble_member_number, strlen);
           :
       char perturbations_scheme(ensemble_member_number, strlen);
           : //etc

Do you agree, or have I misunderstood the example? (if I've misunderstood what follows can be ignored). The relationship between ensemble_member_number, experiment_id, perturbation_scheme can be encoded in this case - to reflect the one degree of freedom.

It is possible to encode this using scalar coordinates too - I think something like:

dimensions:
       strlen = 64;
variables:
       float tas; // example data
           coordinates = 'ensemble_member_number'
           :
       int ensemble_member_number;
           coordinates = 'ensemble_member_number'
           :
       char experiment_id(strlen);
           coordinates = 'ensemble_member_number'
           :
       char perturbations_scheme(strlen);
           coordinates = 'ensemble_member_number'
           : //etc

>From what you say this isn't how these files have been encoded (maybe, as Jonathan says, because the documentation wasn't clear enough?) - so that may be a problem.

I think the above scalar coordinate encoding is, however, clearer - it gives a data user more information on how the data is related.

See you,

Jamie
Received on Fri May 24 2013 - 05:34:54 BST