[QUANTITY] and [OBSERVATION] data models: UCDs with DMs

[Martin Hill]

Francois Bonnarel wrote:

> <	I have always maintained that the string-based UCD approach is very 
> <	flawed, and it the root cause of many of the issues in trying to transition
> <	from UCD1 to 1+/2. I am very much a believer that we should just keep
> <	UCD1 as is, and immediately start work on UCD3. Skip the "intermediate"
> <	steps which aren't going to be very productive as the gap between what
> <	is really needed (a flexible, multi-node interconnected set of semantics)
> <	and what is currently implemented (somewhat inflexible 2-level hierarchy based
> <	on strings) is too wide. An incremental approach will likely be a failure here. 
> <	We need to admit the failures of the present approach and move on.
>      
>       How can something like UCD1 used in various softwares and 
> performing real work be considered as a failure? (And there was a need
> for some simplification- error/fixing - generalization of that --> UCD1+). 
> Except if we put data model theory over all. Not that I do not recognize 
> that the UCD3/ontology approach has  to be performed. I described 
> another conception of the relationship between Data model work and
> actual interoperability in my mail to G Lemson yesterday. 

Failure might be too strong a word, but UCD1 is not sufficient to 
describe data fully enough for complete interoperability. I agree with 
Brian about what we need eventually, but I think the effort going into 
UCD1+/2 is helping to define these things and how they might work. As 
long as we realise they are only steps along the way.

In fact, would combining UCD1++/2+ with structure from the data models 
be sufficient to describe VO data?


-- 
Martin Hill
www.mchill.net
07901 55 24 66