[sc34wg3] Use cases for occurrence variants

[Steve Pepper]

At 20:16 04.03.2003 -0800, Nikita Ogievetsky wrote:
>To get occurrence variants discussion down to Earth
>I suggest that we try to summarize use cases.
>
>Here are those that I know of or have seen mentioned so far:
>
>1. Thumbnail(s) of an image.
>2. Description of an image (displayability).
>3. Alt text (displayability).
>4. Sorting occurrences (sortability).
>5. Alternate address depending on device context, protocol, etc.
>6. Model inconsistency between base names and occurrences.
>
>Any others?

I think that pretty much covers it.

#5. is perhaps the most important, so I would put it at the top and
call it "Alternate renditions" rather than "Alternate address". It
would include alternate notations, resolutions, sizes, etc. For
example, in the XML Papers application, the PDF and HTML versions of
a paper might be variant occurrences of the XML version.

As someone who has been playing devil's advocate and didn't really
want variant occurrences, your list scares me. What it tells me is
that there is a whole range of very useful and necessary functionality
we are excluded from using unless we are prepared to use associations
instead of occurrences. (And even then we don't have an application-
independent way of capturing the relationship between variant forms
of a resource.)

I would almost go as far as to say that without variants, occurrences
are virtually useless. It surprises me that more people haven't thrown
up their hands in despair. Maybe no-one is actually using topic maps?

Steve

--
Steve Pepper, Chief Executive Officer <pepper@ontopia.net>
Convenor, ISO/IEC JTC1/SC34/WG3  Editor, XTM (XML Topic Maps)
Ontopia AS, Waldemar Thranes gt. 98, N-0175 Oslo, Norway.
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