[tei-council] oversimplification: <measure> isn't measured

[David J Birnbaum]

Dear Syd (cc Council),

> * change <height>, <width>, and <depth> to a single element <extent>,
>   which bears a dir= or dim= attribute whose value may be one of
>   "height", "width", and "depth". This new element could be empty
>   (quantity always expressed on quantity=, extent=, or value=
>   attribute) or could have content of text or macro.xtext. (I'd leave
>   it to David and Matthew to decide on that.)
>
> What do you think?
>   

A single element <extent>, which admits an attribute to distinguish 
height from width from depth, creates the opportunity to record multiple 
heights but no width, etc. When I specify the page measurements in a 
manuscript description, I require exactly one height and exactly one 
width, and my (custom) schema keeps me from doubling one or omitting the 
other (these are two completely independent problems). For what it's 
worth, I also specify a fixed order for the two measurements, not 
because one order is inherently better than another (although I think 
that is the case), but because if you permit either order, you increase 
the opportunity for a user not to notice whether he or she has omitted 
something that should not be omitted.

The opportunity to omit a specification that in practice must not be 
omitted or to encode twice a specification that in practice must be 
encoded only once arises frequently in the TEI. It is often a 
consequence of the proliferation of 'repeatable or groups' (although not 
only of 'repeatable or groups'), which have become even more numerous 
since we implemented the class system. We may decide that the benefits 
of that system justify the price (reduced control and precision) in some 
cases, but since we want no more than one height and one width when we 
give the dimensions of a folio (and the same plus depth for certain 
other measurements), would it not be more reliable to use a model that 
reduces the opportunity to deviate from those requirements?

Best,

David