[CF-metadata] Getting back to ensembles

From: Jonathan Gregory <j.m.gregory>
Date: Wed, 3 Jan 2007 18:10:12 +0000

Dear Steve

> I think Bryan has stated the essence of the problem well, below.
> "I think we all understand the distinction between things which are
> measured, and things which are about measurement techniques, or who made
> the measurements (or simulations)."

That is not a requirement, though.

> CF must support standardized terminology in multiple semantic
> domains. It must do so in a manner that will permit tools to be
> built that utilize the distinctions between these domains.

This is a requirement (thanks). But do these tools need the distinctions to
be drawn in the metadata stored in the file? Or do they just need to know
that there are distinctions that can be drawn, to help people construct or
examine files?

> 1. scientifically significant measured quantities
> 2. parameters describing measurement techniques or processes
> (including who made the measurements)
> 3. identification of CF data structures (grids, axes, coordinates,
> coordinate geometry information, ...)

> I'm no metadata expert, so please correct me if the following
> assertion is wrong: There is nothing to prevent the same name from
> existing in multiple vocabularies. For example, if
> "platform_orientation" (mentioned as an example in a previous email)
> really is both a "scientifically significant measured quantity" and a
> "parameter describing measurement technique", then is can exists
> separately under both domains. It do not think it is a requirement
> that the distinction between semantic domains can be inferred from the
> name alone.

If the categories are overlapping, that suggests to me that what we should
do is add a column to the standard name table to indicate which possible
categories a quantity belongs to. It does not require introducing a new
attribute as an alternative to standard_name for metadata stored in the
netCDF file. Using different attributes would require that you decide which
it is, in each case stored in the file, and that would seem arbitrary. Why
would you need to do that? I mean, what tool has a requirement for it?

Best wishes

Jonathan
Received on Wed Jan 03 2007 - 11:10:12 GMT