Units of Measure (BP, Coverages, SSN,Time?)

Hi,

I'm looking into the BP aspects around defining data dimensions as a
framework for evaluating and contributing to various SDW threads. One which
seems to cut across, but I havent seen an explicit treatment of the UoM
problem. I know I may have missed previous conversatiosn - but I dont see
any treatment in the current reviewable docs.

Specifically, if I was to follow the W3C Data on the Web Best Practices I
would be led via BP #2

"To express frequency of update an instance from the Content-Oriented
Guidelines developed as part of the W3C Data Cube Vocabulary efforts was
used."

to this statement:
"To express the value of this attribute we would typically use a common
thesaurus of units of measure. For the sake of this simple example we will
use the DBpedia resource http://dbpedia.org/resource/Year which corresponds
to the topic of the Wikipedia page on "Years".

If we have a Time ontology - surely we would be pointing to that as a
recommendation for temporal units of measure.
Likewise, i would have thought that OGC would have an interest in binding
CRS with their in built units of measure to spatial dimensions.
One could argue that without interoperability at this level there is a
question why the OGC would have any involvement in Web standards - but if
there is a counter-argument then I feel this needs to be front-and-centre
of the BP to explain to a potential user what they can expect, and where
they are going to be left with making all the significant decisions.

If we have Time and CRS UoM, then we may be able to get away with not
specifiying a vocabulary for other UoM for measurements. Are there any
obvious dimensions that need UoM vocabularies?

When I specify O&M profiles, (my driving use case), I'll need to specify
the UoM for measurements - is there any recommendation regarding which
vocabulary to choose?   And for CRS based dimensions?

Rob Atkinson