Hi Stephen,
I think it would be a big mistake to jump to RDF from the current
'flat-string plus attributes'. What do people have against a
straightforward XML-based markup language? I've demonstrated (my email
of 28th Oct) that there can be a simple mapping on to the construction
rules for existing names, it's reasonably readable, and it lends itself
to machine processing.
The example that I find useful to keep in front of us is that of
plain-text equations and Content MathML. They both encode the same
information, but many maths packages use MathML (rather than plain text,
or, heaven forbid, RDF) because it is a good balance between
representing structure explicitly, readability and machine processability.
Cheers,
Robert
Pascoe, S (Stephen) wrote:
Here's an idea that people will either love or hate. What about
defining a convention for embedding RDF triples in NetCDF, in a similar
fashion to what RDFa does in XHTML. This way we could leverage the full
richness of RDF to describe our relationships. The same mechanism would
work in NetCDF, NCML and OpeNDAP because of their shared data model.
The downside is that processing RDF is cumbersome without specialist
libraries and tools.
Cheers,
Stephen.
---
Stephen Pascoe +44 (0)1235 445980
British Atmospheric Data Centre
Rutherford Appleton Laboratory
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of John Caron
Sent: 03 November 2008 15:33
Cc: [email protected]
Subject: Re: [CF-metadata] a different (but perhaps unoriginal) approach
to standard name construction
I would propose that we dont replace the current standard_name
attribute, but explore alternative representations of their semantics.
The goal would be to clarify the relationships of the various semantic
components of a standard quantity, and to explore possible grammers for
generating the name.
While the end product of CF Conventions is to create specific metadata
to be placed in data files, I think we often limit our thinking to the
rather small set of representational forms that can be encoded into the
netCDF-3 (aka classic) data model.
To be specific, standard names are limited to being represented as char
attributes, and so our dialogue about them sometimes seems limited to
sequential "flat space" concepts. Of course actually we have an
extremely rich associative semantic linkage in our minds.
The idea, for me, would be to look for some richer representations of
the associations and relationships between standard quantities, which
could accelerate the process of constructing them. We can then decide if
we want to encode these in a netcdf file using a single standard_name
attribute and/or multiple "standard_name_component" attributes,
auxiliary coordinates, common concepts, or even (god forbid) rdf
triples.
So I think we should start trying out different representations, and not
make any big decisions, until/unless we have something that we like.
Ok, I lied about the rfd triples inside of netcdf, that's not ok. ;^)
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