[CF-metadata] Swath observational data

From: Jonathan Gregory <j.m.gregory>
Date: Thu, 19 Nov 2009 19:40:08 +0000

Dear all

Re this comment of Tim Nightingale's:

> 2) A syntax to identify a relationship between variables in different
> NetCDF files. Sentinel-3 will use the SAFE format, which implements
> products mostly as a bundle of NetCDF files, where each contains a
> distinct dataset. In some cases, referencing attributes such as
> "coordinates" and "ancillary_variables" would, ideally, point to a
> variable in a different dataset.

This is a general problem to which CF doesn't have a solution because it was
conceived as a convention for single netCDF files. However we need a solution
as often several files should be treated as a single dataset.

If the files don't overlap i.e. their contents are complementary, I think it
should be satisfactory to allow variables in one file to be pointed to by name
from another file, with no other mechanism being required within the file. I
don't like the idea of naming one file within another file, as that would be
very fragile. Instead, I think the file aggregation should be implied by
simply defining the group of files which are to be treated as one file e.g.
by putting them in one directory.

If the files do overlap i.e. they have variables with the same name in them,
and probably coordinates to be aggregated, more rules are needed for how and
when to aggregate variables and dimensions.

Cheers

Jonathan
Received on Thu Nov 19 2009 - 12:40:08 GMT