Error column in VOResource->DM-Quantity <=> VOTable-PARAM

[Pierre Didelon]

Hi Roy,

Roy Williams wrote:

Snip
> 
> (2) Pragmatism
> 
> Now we get a whiff of the UCD3 and ontology questions that we discussed last
> year. Who will create and build all this fancy metadata, who will write the
> software that reads it, and who are the clients that want to use it.
> 
> So maybe I come round to agree with you. The most common "relationship"
> between table columns is one of univariate error estimate. So lets just get
> that right and forget the rest. But if that is the philosophy, we should
> forget quite a bit of other VO-related "modelling" activities, right? Maybe
> all this stuff about "Quantity" and "Observation" is just the PARAM element
> in VOTable?

Some part of VOTable are the equivalent of DM concept...
not surprising as VOTable is conceived as a generic container (even if tailored
for table data), so generic description has corresponding structure in VOTable,
but it is not only PARAM.
Let me try to explain my (personnal) point of view, hopping that I am not introducing
too much "noise" in discussion.

For Observation François Bonnarel shows that possible "views" of the data model
can be serialised in VOTable format, but the full functionality of VOTable
is needed to represent it, and it gives only a partial excerpt of the DM.

Concerning Quantity it is eveident that PARAM tag in VOTable can be seen as
a possible serialisation of basicQuantity (atomic quantity with one value),
with one PARAM in a VOTable even VOTable can be used as one possible serialisation of it,
I am not arguing that it must be the realisation of it ( ;-) martin ).
Admitting that, FIELD tag and corresponding column in TABLEDATA can be seen as vectors,
GROUP allow to associate them, TABLE can be used to serialised matrices,
and RESOURCE/VOTable as generic serialisation for N-Cubes.
It is a perhaps a too generic serialisation which do not force semantic
to be included always in the same way, but at least it gives a way of serialisation
which would works with an already existing VO standard...
For me VOTable is a _possible_ serialisation of quantity, but I feel
like an heretic saying that, beeing quite sure that DM people would not agree.
Moreover it has to be assed by DM group first, once they define what are the necessary
informations needed, so that all quantity informations can be serialised in
PARAM/VOTable format.
It has nevertehless the advantage to be an already existing standard,
with available tools in increasing number.

pending lightning and thunderbolt... :-)

Regards,
Pierre