Yeah, the semantic information is there by explicitly mentioning the
BTs, but not the NTs. The NTs are there by inference since they are
symmetric, it's all still there. That's a fine practice.
But if memory serves, even those original BT's were in some cases
machine generated to get the ball rolling. The LCSH in it's entirety was
just too large to do all by hand, when they started adding those BT/NTs
(the 80s sometime?). If I'm remembering right.
It's interesting news to me that III OPAC has been taking advantage of
these for a while though, thanks for the pointer, I plan to investigate
what they've done.
Jonathan
Hahn, Harvey wrote:
> Jonathan Rochkind wrote:
> |I think the path to this is in the BT (broader term)/NT (narrower term)
> |"cross-reference" relationships which _are_ included in (much, but I
> |don't think yet all) LCSH, as of a couple decades ago. Although they
> |are not usually shown to the user at all.
>
> As I recall, the standard rule in LCSH is that you make BT references,
> but you *never* make NT references. NT references are machine-generated
> at the higher level from the lower level BT references. (Otherwise, NT
> refs are a nightmare to maintain.) The "trickier" one was that, if a
> term had both BT and NT references with another term, then both terms
> had RT references automatically machine-generated in place of the BT/NT
> references.
>
> |Of course, while they are in LCSH, the fact that they've never been
> used
> |for much of anything useful in a mass-processed way (just cataloger
> |guidance), means that who knows if they will really work.
>
> To my knowledge, they've been part of the Innovative Interfaces system
> for quite a number of years, but *how* they work (user interface
> aspects) may leave something to be desired. Play around in some III
> catalogs to see these xrefs at work
> <http://www.librarytechnology.org/lwc-search-advanced.pl?SID=20050314236
> 114501&UID=&auth=&code=lwc>, clicking the "Current Automation System"
> dropdown button and choosing "Millennium". [I can't refer you to our
> catalog because, unfortunately, past practice at our library was to
> remove these since, originally, the *codes* in subfield w displayed to
> the public for each subject heading containing subfield w, creating a
> mess on the screen.]
>
> Harvey
>
> --
> ===========================================
> Harvey E. Hahn, Manager, Technical Services Department
> Arlington Heights (Illinois) Memorial Library
> 847/506-2644 - FX: 847/506-2650 - Email: hhahn(at)ahml(dot)info
> OML & Scripts web pages: http://www.ahml.info/oml/
> Personal web pages: http://users.anet.com/~packrat
>
>
--
Jonathan Rochkind
Sr. Programmer/Analyst
The Sheridan Libraries
Johns Hopkins University
410.516.8886
rochkind (at) jhu.edu
Received on Wed May 09 2007 - 15:02:08 EDT