[Sigia-l] Facets vs. ontologies [was: Sigia-l] Findability - hierarchies

[Peter VanDijck]

> | It does seem to misrepresent the purpose of facets however, which is
> | to reflect fundamentally different aspects of the things we are
> | categorising (such as business areas and geographical locations).
> 
> That's true, and that's why I qualified this in the paragraph
> following the one you quoted. Still, the fact remains that the
> division into facets is a very weak form of structure.

Yes - if compared to ontologies. However, a simple division into facets
makes it possible to make very powerful NAVIGATION widgets/systems (see
Facetmap). I haven't seen any really good navigation widgets/systems for
the more advanced ontology structures - it is usually just see-also and
some ways of combining queries. My point is: we have some idea of how to
build powerful navigation with Facets only, and adding a full blown
ontology to that doesn't really add much to the navigational
capabilities. (Please disagree/discuss if you will - I'm making this up
as I go)

> | Even the BT/NT hierarchy at the centre of the taxonomy may sometimes
> | be a polyhierarchy (more than one parent) rather than a strict
> | hierarchy.
> True. I don't have enough experience with thesauri to know whether
> this is a bug or a feature. It seems to me that in something as weakly
> structured as a thesaurus attaching a node to multiple parents is a
> bit dangerous and something that can quickly lead to chaotic
> structures.

Polyhierarchy is a feature for thesauri (from a classification point of
view). The thing is: thesauri were never really structured for computer
use. The thesauri structure is weak indeed, because they weren't
designed by programmers. The whole programmer perspective (see what
Travis is doing with structures in Facetmap, or see topicmaps) can add a
lot of value to classification structures in general. I think thesauri
in their old form are old school.

> * Lars Marius Garshol
> |
> | What you'd really want to say is something like this:
> |
> |   "Oil services" is a "business area"
> |   "Oil surveying" is a "department"
> |   "Kano field location" is an "office"
> |   "Oil production" is a "department"
> |
> |   "Africa" is a "continent"
> |   "Nigeria" is a "country"
> |   "Kano" is a "place"
> |   "Morocco" is a "country"
> |
> |   "Kano field location" is "located in" "Kano"
> Could you really express this in a faceted hierarchy? 


Let's try:

- Geography (facet)
-- Africa
--- Morocco
--- Nigeria
---- Kano (assuming Kano is in Nigeria)
- Business areas (facet)
-- oil services
- departments
-- oil surveying
-- oil production
- type of location
-- office

"Kano Field Location" would be classified in office, Kano and maybe some
business areas and departments.

Faceted hierarchies are definitely less powerful than ontologies, as in
what they can express. But which system is easier to work
with/implement? (this is not a rethoric question)
PeterV