[GO-ESSP] RE: [NERC-DataGrid] Units and NERC DataGrid

[K. A. Bouton]

Not that we can save you a job, but in building the structure for the model
metadata we are coming to similar conclusions, and thinking we have to do it
sooner than later. We are taking the PRISM/CF approach where we start with a
list compiled by a few of those in the know and work from there - Lois calls
it the benevolent dictator approach :)



> -----Original Message-----
> From: nerc-datagrid-bounces at ncas.ac.uk 
> [mailto:nerc-datagrid-bounces at ncas.ac.uk] On Behalf Of Roy Lowry
> Sent: Monday, December 06, 2004 10:41 AM
> To: pm286 at cam.ac.uk; b.n.lawrence at rl.ac.uk
> Cc: NERC-datagrid at ncas.ac.uk; rkl at bodc.ac.uk; 
> sgxml at biwebs.nerc-liv.ac.uk; mmi-tech at mbari.org; 
> lbartolo at kent.edu; GO-Essp at ucar.edu; 
> chris.little at metoffice.gov.uk; rlake at galdosinc.com; 
> caron at unidata.ucar.edu; RobertM at dessci.com
> Subject: [NERC-DataGrid] Units and NERC DataGrid
> 
> 
> Bryan/Peter,
> 
> I have been giving some thought about what to do about units 
> in NERC DataGrid as we get to the stage where vocabularies 
> become today's problem rather than tomorrow's.
> 
> The first issue to address is what to do about 
> standardisation.  The oceanographic community has been trying 
> for years to standardise the units people use for specific 
> parameters.  The degree of success, with good reason, has 
> declined dramatically as one goes from physical to chemical 
> to biological domains.  It is therefore clear that in NERC 
> DataGrid we are going to have to deal with the situation 
> where different data hosts store the same parameter in 
> different units.  In other words, whilst we can recommend 
> standardisation I cannot see how we can enforce it and so we 
> need to engineer for what's really out there (remember I deal 
> in measurements, not model outputs).
> 
> The solution has to lie in the philosophical approach taken 
> by UDUNITS, but this will require significant extension to do 
> the job we need.  We also need to take a more pragmatic 
> approach than dimensionality/canonical units to allow 
> interoperability between data sets where scale not 
> dimensionality is the issue.
> 
> I also feel that what we need is more along the lines of a 
> semantic web resource rather than a downloadable executable 
> approach: in other words a units ontology that provides a 
> units vocabulary plus the knowledge about which units may be 
> interconverted and how.  Such an ontology could be 
> interlinked with parameter vocabularies indicating the subset 
> of units that may sensibly be associated with particular parameters.
> 
> Before embarking on building such an ontology for NERC 
> DataGrid, I am circulating this e-mail far and wide 
> (apologies for  multiple postings) to obtain answers to two 
> simple questions.
> 
> What do you think of this approach?
> 
> More importantly:
> 
> Does anybody know of anybody who is building/has built such 
> an ontlogy and can save me a job?
> 
> Cheers, Roy
> 
>  
> 
> 
> 
> Please note my new address:
> 
> BODC
> Joseph Proudman Building
> 6 Brownlow Street
> Liverpool L3 5DA
> 
> Direct dial phone - +44 151 795 4895
> E-mail: rkl at bodc.ac.uk
> 
> 
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