[QUANTITY] Requirements and apology

[David Berry]

Doug,

> If we are talking about data values, WCS, data quality, etc., then we
> are modeling an entire dataset, not a quantity.  We need to address both
> issues but they are at opposite ends of the spectrum.  Quantity needs
> to be a low level concept (about the same level as a UCD) or it is being
> confused with something else.

I would be happy to call it a "dataset" instead of a "quantity". If a
Quantity was simply a combination of a UCD and a Units object, then
a "dataset" would come in between Component and Quantity in terms of
the Container/Component/Quantity hierarchy you outline in a recent
message - Component would contain zero, one or more DataSets; and DataSet
would contain zero or one Quantities.

David