> I think it would be a big mistake to jump to RDF from the current
'flat-string plus attributes'.
As I say, people will either love or hate it. It was a provocative
suggestion because I don't believe just thinking up an XML format solves
the problem. I'm with John that we need to clarify the concepts and
relationships within standard_names rather than focussing on the syntax.
Adopting a new syntax before we understand what we are modelling would
be a distraction. At least with RDF the relationship between syntax and
semantics is already there.
However, I'm not seriously suggesting CF community adopt RDF in the near
future; maybe something worth exploring. The common concept proposal is
another way to go because it would allow us to break out of the
straightjacket of "standard_name says it all" whilst keeping within the
same syntactic framework of NetCDF attributes.
MathML is an interesting example if you want to advocate a "simple" XML
format. I see it as a good example of how life gets really complicated
when you start modelling semantics and why we might not want to start
down the road of another XML format. In MathML 2.0 there were 2 types
of MathML -- Presentation and Content. In MathML 3.0 there are 3 or 4
-- Presentation MathML, Content MathML, Strict Content MathML and
OpenMath (not part of the standard but referenced by Strict C. MathML).
How many tools do you know that understand anything other than
Presentation MathML? I assume they do exist but I don't know of any in
the OpenSource world.
Cheers,
Stephen.
-----Original Message-----
From: Robert Muetzelfeldt [mailto:r.muetzelfeldt at ed.ac.uk]
Sent: Tue 04/11/2008 12:56
To: Pascoe, S (Stephen)
Cc: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] a different (but perhaps unoriginal) approach
to standard name construction
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: cf-metadata-bounces at cgd.ucar.edu
> [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of John Caron
> Sent: 03 November 2008 15:33
> Cc: cf-metadata at cgd.ucar.edu
> 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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Received on Fri Nov 07 2008 - 08:21:01 GMT
