Linking lcsh and other stuff

Linking Library of Congress Subject Headings

Owen Stephens 14th July 2011@ostephens

http://www.meanboyfriend.com/overdue_ideas

Thursday, 14 July 2011

LNKNLCSH@ostephens


This is the lightning version

I should precursor this talk by saying I’m really pleased that the LoC have invested in experimenting with Linked Data representations of aspects of their data. Anything in this talk isn’t a criticism of this, but about the issues we encountered using aspects of the data. It’s possible that some or all of these problems may have been down to my lack of understanding of LCSH and Linked Data :)

Library chops


I’m a librarian - by nature and qualification :) - see http://www.meanboyfriend.com/overdue_ideas/2010/11/library-routes/

Been working on the cusp between libraries and IT since 1995. Spending early part of my career in small libraries means I have worked in just about every area of library front of house and back office. However although I’ve catalogued books, and have more than a passing familiarly with MARC, I’m not a cataloguer, and not an expert on LCSH

Linked Data chops


I’ve been trying to understand the Semantic Web/Linked Data for several years :) My understanding has been accelerated over the last couple of years by involvement in several projects in the Linked Data space. Specifically the Lucero and CORE projects at the Open University


Expressing similarity between published papers in UK research repositoriesHarvest metadata and full-text (50k papers from 143 UK repos so far)Text mine for relationshipsExpose ‘similarity’ measure as RDF triples using MuSIM Ontology (originally developed for Music, but equally applicable)For more information http://core-project.kmi.open.ac.uk

Exposing RDF


Three ʻproductsʼCORE Portal - search or SPARQL metadata for harvested papers CORE Mobile – Android application to search & navigate across related papers & downloading articlesCORE Plugin - Designed to integrate into existing repository interface to link to ʻrelated papersʼ in other repos, based on CORE ʻsimilarityʼ

For more information http://core-project.kmi.open.ac.ukSPARQL Endpoint at http://core.kmi.open.ac.uk:8081/COREWeb/squeryHow we express data in RDF: http://core-project.kmi.open.ac.uk/node/13

Lucero


For more information see http://lucero-project.infoData and SPARQL Endpoint available via http://data.open.ac.uk

Lucero published variety of data from the Open University as linked open data - admin data (buildings), course data (course catalogue, OERs), research data and data about bibliographic resources - including materials in the library (focussed on materials related to course materials - around 30k catalogue records)

LCSH

Thursday, 14 July 2011Lots been written about LCSH, it’s structure, whether it should be replaced. I don’t want to spend too much time on this today but it may come up in places

However it is probably worth recapping my understanding (if only to let those more knowledgeable correct it)

Key aspect in the context of this talk is that LCSH is primarily a pre-coordinated system - that is facets of subject headings are pre-combined into a single, multi-faceted heading. Although....“LCSH itself requires some degree of post-coordination of the pre-coordinated strings to bring out specific topics of works.” (http://www.loc.gov/catdir/cpso/pre_vs_post.pdf)

In fact the way that LCSH is structured in MARC records, and the way that indexes can be built on this in library management systems means that

I’m going to focus on ‘Topical’ subject headings (confusingly to me, LCSH can also cover Name, Title and Geographic headings)

Topical Terms can represent “a concrete object, animal, etc.; a category of people, animals, or objects; a more abstract concept, belief, process, or phenomenon; an institution, etc.” (http://www.tulane.edu/~techserv/lcsh%20introd.html) Topical LC Subject Headings are built by combining ‘Topical Terms’ with qualifiers (‘subdivisions’) which allow you to contextualise the term. The types of subdivision available are:

General (a high level general qualifier - e.g. ‘History’)Chronological (period of time - e.g. ‘20th Century’)Geographic (place - e.g. ‘Great Britain’)Form (the type/genre of material - e.g. ‘Dictionary’)

There are large number of rules that express how these subdivisions can be used in conjunction with Topical Terms, and the order in which they should be expressed. Not all combinations are valid - for example only certain General subdivisions may be further subdivided Geographically. The rules are not always black and white - they have ‘examples’ lists which you can use to inform you if it might be valid in a given situation.

Perhaps suffice to say that a document called ‘BASIC SUBJECT CATALOGING USING LCSH: Trainee’s Manual’ is 382 pages long.

Subject heading strings can be valid (i.e. constructed according to rules/patterns) while not being ‘Authorized’ - in this context and Authorized Heading is “A preferred subject term as decided and established by the Library of Congress by means of an authority record.” (Thanks to Tom Meehan for this definition)


Thanks to work of Ed Summers and others, the Library of Congress have a Linked Data representation of LCSH in SKOS. However, this only covers ‘Authorized’ LCSH - presumably because only those LCSH with an Authority record have an identifier within LoC systems? (I’m speculating)


This is a catalogue record from the OU - the two strings listed as ‘Subjects’ are LCSH (for cataloguers amongst you MARC 650s)

Can see the linked data representation at http://data.open.ac.uk/page/library/289148

Science--Study and Teaching--Research

Topical Term

General Subdivision

General Subdivision


This is made up of a Topical Term - Science and two general subdivisions ‘Study and Teaching’ and ‘Research’


id.loc.gov ?


This is (afaik - I trust the cataloguers) a valid LCSH ... however it is not authorized ... and so does not have a URI on id.loc.gov


http://id.loc.gov/authorities/sh85118587#concept


“Science--Study and Teaching”, however, is an authorized heading



N.B. This is URI for Science as Topical Term not http://id.loc.gov/authorities/sh00007934#concept which is URI for Science as a General Subdivision


As is “Science”




Also “Study and Teaching” (as a topical subdivision) is an authorized heading



N.B. This is URI for Research as General Subdivision not http://id.loc.gov/authorities/

sh85113021#concept which is URI for Research as a Topical Term


Also “Research” (as a topical subdivision) is an authorized heading

More links please


If we only used id.loc.gov URIs where we had an authorised LCSH, we would end up with only a small number of links. Some URIs in id.loc.gov would never be used in this way as they only represent subdivisions - never valid by themselves.

Therefor decided to check a variety of combinations against id.loc.gov

Science--Study and teaching

Science--Study and Teaching--Researchhttp://id.loc.gov/authorities/

sh85118587#concept

Science

Study and Teaching



Research http://id.loc.gov/authorities/sh2002006576#concept


http://data.open.ac.uk/page/topic/library/science--

study_and_teaching--research





http://data.open.ac.uk/page/topic/library/science--study_and_teaching--research






MADS?

http://www.loc.gov/standards/mads/rdf/


As far as I can see MADS (apart from looking complex) models the Authority - not the heading - this doesn’t solve the problem we saw here!

That is MADS would solve the problem only for Authorized headings (which it does represent as component parts - which I think addresses the issues raised by Karen Coyle at http://kcoyle.blogspot.com/2009/05/lcsh-as-linked-data-beyond-dash-dash.html)

Happy to be corrected...

bibo:authorList ( <http://examples.net/contributors/2> <http://examples.net/contributors/1>)

lcsh:headingList ( <http://id.loc.gov/authorities/sh85118553#concept> <http://id.loc.gov/authorities/

sh2001008697#concept> <http://id.loc.gov/authorities/sh2002006576#concept>)

A different approach?


If we could use rdfs:list to represent the pre-coordinated string of headings - then wouldn’t care about whether ‘authorized’ or not, and would have all the individual headings there as well (bibo lists authors individual and as a list)

Again copying BIBO which has each author as a dc:author as well, could represent each part of the subject string as a separate dc:subject.

In a MADS world there would be advantage to expressing full authorized heading as well (for relationships derived in MADS) although there is still the question of expressing ‘authorized fragments’ which seems to me would also be useful with MADS for the same reasons

This feels like a simple approach that would at least allow us to capture the component parts of subject string (and personally I’m not sure we ought to go further than this? do we need to? why?). My feeling is lots of the work goes into representing the ‘Authority file’ as opposed to how subject headings are used in the real world ... is this fair?



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Linking lcsh and other stuff