[CF-metadata] Getting back to ensembles

From: Brian Eaton <eaton>
Date: Mon, 20 Nov 2006 11:48:01 -0700

Hi John,

On Mon, Nov 20, 2006 at 11:12:00AM -0700, John Caron wrote:
>
> let me munge your examples slightly:
>
> 1)
> float temperature(rdim,time,lat,lon):
> temperature:coordinates = 'realization time lat lon' ;
>
> char realization (rdim, strlen):
>
> assuming that time,lat,lon are the usual CF conventions, then the new thing
> is that I have a string valued coordinate, but i dont know what it is
> intended to mean. But if I unambiguously indicate it as:

The "new" thing isn't new at all. This is a label coordinate as described
in CF-1.0 section 6.

>
> char realization (rdim, strlen):
> realization :standard_name="realization"; // or whatever we decide
>
> Now I know its an ensemble dimension, and can present it to the user for
> slicing and dicing, in a way that the user knows for sure what the
> dimension is used for. I would require that the strings are unique, so
> there is a 1-1 mapping. What the string values are doesnt matter to me.

CF places no restriction on the uniqueness of labels in a label
coordinate. Typically one would "slice" a label coordinate by asking for
the subset of elements whose labels matched the string "xxx". It's not
clear to me why you want to require a 1-1 mapping (I'm assuming the mapping
you refer to is between the labels and the array indices).

Brian
Received on Mon Nov 20 2006 - 11:48:01 GMT