Quoting Jonathan Rochkind <[email protected]>:
But if we don't have any accessible means of mapping from LCC to
LCSH... then it's not an option. So do nothing, or do something
else?
Hmm, what if you displayed the LCC headings in the shelf browse,
_and_ included them in the index as searchable, to meet the "if you
display it, the user should be able to search it" rule. But of
course you don't stop indexing LCSH either -- LCC is a bad 'entry
vocabulary', we don't expect anyone to use it 'naturally' -- but if
they see it on the shelf browse and then want to use it to perform
searches, at least they can.
I don't have access to LCC so I don't know what their "labels" look
like on the class numbers. I have only vague recollections based on
the examples in the MARC classification format. So it isn't clear to
me if they will be good ones to show users. I am pretty sure that the
records contain a portion of hierarchy that provides context, e.g.
(from the online classification MARC standard):
$aPQ4315.25$hItalian literature$hIndividual authors.$hIndividual
authors and works to 1400.$hDante Alighieri,
1265-1321.$hTranslations$hEnglish.$hDivina
commedia.$hInferno.$jParticular cantos
Since both LCC and LCSH are "syndetic" -- that is, the actual
instances get built from a set of rules and lists -- no version of
either standard will be complete (although I hear that LC is trying to
include more pre-composed instances in the id.loc.gov version of LCSH,
probably for this reason). This means that what you have in the
record, in many cases, will not match what is in the standard. That's
why I though FAST would be interesting because it could include those
standard lists. But I am also told that id.loc.gov has a lot of those
standard lists in it... Which means that, as usual, you've got a bit
of a mess -- some of your headings/class numbers will match, some will
need an add-on to match, it's not clear if you can identify the
added-on portion, especially in LCC, because the class numbers are not
hierarchical the way they are in Dewey.
Another note/oddity is that LCSH has what they call "pattern" headings
-- so there are few people included in LCSH (people are in the LC
Names file) but you can find Shakespeare because he's the pattern for
authors:
http://id.loc.gov/authorities/subjects/sh85120847.html
and there are others who are patterns for historical figures, etc. (I
think George Washington is one.) So again you've got something that
isn't complete for matching except in a few instances. (All other
authors MAY have the same subheadings as Shakespeare, but they won't
be in the subject file; there will just be a name in the LC Names file.)
Essentially, the digital versions of LCSH and LCC derive from the
instruction tomes that were used by subject catalogers. They aren't a
complete list of either the call numbers nor the subject headings, but
they explain how to create instances of LCC and LCSH. For this reason,
although it is great to have them in a machine-readable form, it
doesn't get you what you would often expect from a controlled
vocabulary list, which is a complete list of the vocabulary that you
can use for matching.
Another note (then I'll shut up): In LCSH cross references are not
made to all of the headings that could use them, it's kind of a
cascading thing. This is made up, but it works like this:
USA
use: United States
But no:
USA. Post office
use: United States Post office
The entry vocabulary assumes that you have started alphabetically and
have "seen" the reference. If you want to provide that capability in a
system you have to create your own xrefs using all of the possible
patterns...
Now I'm really depressed, and I'll stop.
kc
It would certainly be better if we had one vocabulary we could use
for all things that serves all purposes, but it's just not the
current environment. Even if you did have an accessible means of
mapping from LCC to LCSH (I don't think anyone other than maybe OCLC
does; and I am not sure if even OCLC shares it with members in a
flexible machine readable way, unless maybe the Terminologies
Service does), even if you did have that... I wonder, if LCC works
better hieararchically for a shelf browse label, if you might still
want to show both LCC and LCSH as labels in a shelf browse.
Quoting Jonathan Rochkind <[email protected]>:
Ah, but we're not talking about "entry vocabulary", we're talking
about labelling shelf ranges.
At my job at UC we had a rule: if you display it, the user should
be able to search it and get those same results. If you display one
set of strings as a shelf label, and a different set of strings are
required for retrieval, that's going to be confusing. Ideally users
should be able to search within the classification scheme, or to
navigate around, but we don't have that ability. The point of my
blog post is that we have separate systems and it can't be clear to
users how they interact. (I'm not even sure they do interact
cleanly.) The only way users can make sense of things is by
extrapolating from what we display to them. I worry that seeing
inside LCC, while being given only LCSH to search on, isn't going
to be clear. While LCSH loses a lot of the structure of LCC, at
least users are seeing what they would need to search on in the
catalog to get those same results.
kc
But I agree that the headings for LCC will be less user friendly
than LCSH. If there was a way to get LCC-to-LCSH mappings in an
easily usable way without paying tens of thousands of dollars,
that would be clever. (I'm not sure there's a way to get them even
if you DO pay millions of dollars).
So I was suggesting using the LCC headings themselves as a more
feasible alternate plan, is all. I agree it would be insufficient
if we needed an "entry vocabulary". But just for labelling shelf
ranges on display, I think it's probably not worse than nothing.
Of course, that's up to the implementer, what's better than nothing.
Quoting Jonathan Rochkind <[email protected]>:
For #2, you can provide a useful topical/subject type heading
via much simpler and more feasible solutions than mapping to
LCSH. For #2, you don't need a map to LCSH, you need the LCC
schedules with descriptions of what each range of LCC call
numbers is for, in machine-readable form.
I would give the opposite advice. LCC will have fewer
pre-composed headings than LCSH at id.loc.gov, and the
terminology associated with the numbers in digital LCC will be
less user-centric than the LCSH subject headings. cf my most
recent blog post:
http://kcoyle.blogspot.com/2011/10/relativ-index.html
There isn't any entry vocabulary for users other than LCSH --
which isn't really entry vocabulary to LCC and is definitely NOT
entry vocabulary to DDC.
kc
Thanks everybody!
this is useful for a couple of purposes
1) sometimes we have records that have call numbers, but no
subject headings.
this would be useful to provide those.
2) i'm thinking of providing a 'subject heading' label to our
shelf browser --
so users see, in addition to the callnumber -- what the call
number means.
thanks again!
rick
On Tue, Oct 18, 2011 at 2:33 PM, Jonathan
Rochkind<[email protected]> wrote:
Anyone know if the OCLC Terminology Service provides such a
mapping? The
Terminology Service may be free if you are already an OCLC cataloging
member.
At one point I think I saw an absolutely free open access
machine readable
mapping somewhere, that was made at some point in the past and
no longer
updated... but I cant' remember where I saw that even.
LC's Classification Web provides a mapping from LC classifications to
LC subject headings. There is a manual web interface, used mainly by
catalogers, which requires a subscription:
http://classificationweb.net/
I don't know if it has any kind of API.
Keith
On Tue, Oct 18, 2011 at 2:11 PM, Enrico Silterra<[email protected]>
wrote:
is there any way to go from a LC call number,
like DF853 to http://id.loc.gov/authorities/subjects/sh85057107
via some sort of api? opensearch?
thanks,
rick
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