Table Of ContentLinked open data for new library
services: the example of data.bnf.fr
RomainWenz
Library catalogues were designed to locate books and to handle
collections. They are used by librarians collecting books and by
users finding them. Yet, it can be hard for a user to reach library
informationontheweb,especiallyastherecanbeseveralcatalogues
foronelibrary. Indeed,differentkindsoftoolsarerequiredfordif-
ferentkindsofcollections. Forinstance,acollectionofarchivesand
manuscriptsneedsahierarchicalstructure,todescribedocuments
together,astheywereproducedandreceivedduringtheactivities
ofaperson. Thereforemanagingdocumentscanbedifferentgoal
frommakingaccesstothem. Webusershavenewexpectationsand
newhabitsinachangingwebenvironment. Librarydatashould
meettheseneedsandtrulybelongtotheweb. Librariestrytomake
theirdatareallyusefulontheweb. Wewillfocusontheusecase
ofdata.bnf.fr,aprojectfromtheBibliothèquenationaledeFrance
thatreliesonefficientlinks,automatictechniquesandsemanticweb
tools.
JLIS.it.Vol.4,n.1(Gennaio/January2013).
DOI:10.4403/jlis.it-5509
R.Wenz,Linkedopendatafornewlibraryservices
New expectations
Onlinecataloguesmakethingsdifferent. Withtheworldwideweb,
researchers have access to plenty of resources from a single com-
puter, even from home. There is now some kind of competition
betweendocumentproviders,sinceitisaloteasiertoswitchfrom
one to another. For instance, a copy of book will be less needed
once it is digitized and available online. The theories of Walter
Benjaminshowedthatcontentislosingitsvalueonceitiscopied
with industrial processes, which is very true in the digital world.
Ontheotherhandonlineaccesscreatesanotherkindofvalue, at
leastforculturalandeducationalresources,whicharemeanttobe
spread. Theresourcesprovidedbylibrarieshavetobeeasytofind,
becausetheybecomepartofamoregeneral“websearch”. There
arealwaysmoredocumentsonline: manyspecificwebsitesprovide
informationwhichcanbecomparedtowhatcanbepublishedin
books. Moreover,digitalcollectionspublishedbylibrariesbecome
partoftheweb. Forreaderswhoarelookingforresourcesonthe
Internet,textsfromdigitizedbooksprovideinformation,likeother
webpages. Thatiswhydigitalcollections,butalsoonlinereferences
ofphysicalbooks, havetobeeasytofindandaccessiblethrough
automaticprograms. Thegeneralpubliccanfindsomedocuments
withoutevenknowingtheyexist.Typically,withtheuseofpowerful
searchengines,usersnowcommonlysearchwithkeywordassoci-
atedwiththefinaldocument. Thishabitwasspreadinadecade.
It has made all kinds of online information always easier to find,
throughtheuseofsearchengines. Thisimpliesthatuserstendto
searchwithkeywordsassociatedtogether,asopposed,forinstance,
asusingaseriesoffieldsasincatalogues. Italsomeansthatresults
sortedbyalgorithmsarecommonlyaccepted. Weareallfamiliar
with sentences such as “results 1 to 10 on 120000”: noise is not a
problem,ifitcomesaftertherelevantresults,foundautomatically
JLIS.it. Vol.4,n.1(Gennaio/January2013).Art.#5509 p.404
JLIS.it.Vol.4,n.1(Gennaio/January2013)
andpresentedfirst. Howshouldlibrariestakeadvantageofthese
evolutions? Severalsourcesofinformationcanhelpus,inorderto
decide how to adapt. First, the statistics of our local search inter-
faces provide accurate and free feedback on what our traditional
userssearch. Forinstance, someyearsagopeopleusedtosearch
for “complete works” of writers, knowing in advance what they
would find in the book. Now, we mainly have searches for the
booksthemselves,typicallywiththetitleofthebookandnameof
thewriter. Publicsurveysfrombythelibrariesorotherinstitutions
showthat,usingsearchenginesforbrowsingthewebhasnowbe-
comeahabit. Internetusersusuallyfindbibliographicreferences
onlinebeforegoingtothephysicallibrary. Thisisconfirmedbyall
theusersurveysmadethosepastfewyears,forstudentsaswellas
forresearchers,astheonesmadebyOCLC,1andbytheBibliothèque
nationaledeFrance.2 Therefore,bookreferencesthatareimpossi-
bletofindonlinearealmostuselessformostpeople. Iflibrarians
want them to be found, they have to put those references on the
web. Mostcataloguesareavailableonlinewithaspecificportal. But
they are usually not accessible from web link, and impossible to
crawlforsearchengines. Thosenewexpectationsfromthepublic
areessentialforlibraries,becauseofthesizeofthecontentowned
by libraries. The amount of content and information available is
sohugethatthemostrecenttechniqueshavetobeusedtohandle
them. Forinstance,theBibliothèquenationaledeFrancedisplays
1,5millionobjectsinGallica,3whichisthebiggestFrench-speaking
digitalLibrary,and12millionbibliographicrecords,thankstothe
legaldepositoftheFrenchedition. Thousandsofmanuscriptsand
archives are also available, with all types of resources, from me-
dievalmanuscriptstoarchivalfondsofmodernwriters. Handling
1Forinstancehttp://www.oclc.org/reports/onlinecatalogs.
2Forinstancehttp://www.bnf.fr/documents/enquete_gallica_2011_rapport.pdf.
3http://gallica.bnf.fr.
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R.Wenz,Linkedopendatafornewlibraryservices
thiskindofresourcescreatesseveralscaleissues,aswearedealing
withmillionsofdocuments. Therearealwaysduplicates,andthe
qualityofthedataisirregular,asaresultofthelonghistoryofour
catalogue. Moreover, printedbooksandmanuscriptsareusually
describedwithvariouslogics,insidethecatalogues. Recordsfrom
themaincataloguedescribeaphysicalbook, usuallyinaMARC
format. Theyarestructureddeliberatelyaroundacollectionwhich
wasconstructedonpurpose,withaseriesofbooksthatwouldbe
shelved together and make sense for the end-user. On the other
hand, archival were produced and received during the activities
ofaperson, andconsideredinawayas“by-products”ofthelife
andactivitiesofsomepersonororganisation. Thedocumentswere
gatheredaccordingtothislogic,whichisnotalwaysobviousforthe
end-usertoday. Therefore,thedocumentscannotbedescribedwith
simple“records”,butwiththemodelofahierarchicaltree,which
makesitpossibletounderstandtheoriginallogicofthearchives.
Theformatwhichiscommonlyusedforthiskindofresourcesatthe
BibliothèquenationaledeFranceisXML-EAD(EncodingArchive
Description). The digital collections, available in Gallica, are de-
scribed with a simple format: Dublin Core. All digital items are
accessiblewithapersistentidentifier(ARK),givenandmaintained
bytheBibliothèquenationaledeFrance. Betweenthesecatalogues,
efficient links have to be provided, so that the users can browse
quicklyandgosimplyfromonedocumenttoanother. Machinesare
notintelligent,soitisnecessarytoprovidestructuredinformation
inthecatalogues,withefficientlinksbetweenthedocuments.
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JLIS.it.Vol.4,n.1(Gennaio/January2013)
Importance of efficient Links : principles in
data.bnf.fr
Ifwewanttheresourcestobetrulypartoftheweb,inthesense
that users can quote them on sites, blogs, pages, and e-mails for
instance,andaccessthembyfollowinglinks,wehavetogivethem
proper identifiers, and to comply with web standards. Thus it is
alsopossibletolinkresourcesfromourdifferentdatasets. Asbig
librariesoftenhaveseveralcatalogues,makinglinksbetweenthem
makesitpossibletofindresourceswithouthavingtolearnhowto
useallthedifferenttools,justby“followingone’snose”. Itmakesit
possibletohandlelibrarydataatlargescale,withdifferenttypesof
documents. Thisisveryimportantsincemanydistinctionsbetween
documentsweremadebeforetheweb.Forinstance,fortheend-user,
adigitized“regularbook”andadigitizedmedievalmanuscriptcan
beequal,inthesensethatthesameusercanaccesstheminthesame
wayiftheyareonline. Theverynotionof“specialcollections”can
change if they are digitized and available on the web. This form
ofopennessisaccomplishedthroughdigitizationprocesses. Inthe
contextofdigitization,manyresourceswhichwereinterestingonly
forspecializedscholarshavebecomerelevantforabroaderpublic.
Forinstance,medievalminiaturesaresurprisinglyusedbyavery
broad public once they are online. The way to search has to be
simplefortheseresources,opentothewebwithdigitization. They
havetobeeasytofindinsidedatabasesbutalsoavailablethrough
linksontheworldwideweb. Ingeneralcataloguesaswellasfor
digitalcollectionsmetadata,thedatadescribingdocumentshasto
betechnicallyavailable,butalsolegallyre-usableifwewantittobe
broadlyspread. Thisiswhymanylibrariesmovetothetechniques
of the semantic Web, together with licenses of “open data”. This
way,somelibrariesarepartofthe“linkedopendata”movement
JLIS.it. Vol.4,n.1(Gennaio/January2013).Art.#5509 p.407
R.Wenz,Linkedopendatafornewlibraryservices
andareinvolvedinthedevelopmentofthe“semanticweb”. The
BibliothèquenationaledeFrancedevelopsanewproject,bringing
togetherdatafromcatalogues(MARC),archives(EAD)anddigital
resources(DC).Allthedataareextractedandgatheredautomati-
cally. Thisproject,calleddata.bnf.fr,4isstillayoungproject,asithas
beenonlineforayear. Data.bnf.frgathersdescriptiveinformation,
andlinksdirectlytoonlinecataloguesanddigitaldocuments. There
areseveralaspects: afirstgoalistomaketheinformationcompliant
withthe“semanticweb”standards,byprovidingpersistentidenti-
fiersfortheresources,withaRDFviewontheavailableinformation.
For the library, gathering information around concepts of works,
writersandsubjectsalsoimpliestoworkonmodellingissues. In
fact, it is a first opportunity to implement the FRBR model, and
touseitwithautomatedmatchingandalignments. Todoso, we
useafreesoftware,calledCubicWeb.5 Thisisnotonlyatechnical
issue,butalsoawaytogetafirstfeedbackonwhatispossible,and
how users react. Therefore, it is very important to publish both
structureddataforcomputers,andwebpages,quickandeasyto
useforhumans.
Figure1:data.bnf.fr.
4http://data.bnf.fr.
5Siteanddocumentationathttp://www.cubicweb.organdhttp://docs.cubicweb.
org.
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JLIS.it.Vol.4,n.1(Gennaio/January2013)
Soastocomplywiththe“semanticweb”principles,itisessential
toprovideinformationwhichisdescribedwithcommonvocabular-
ies,withastrictstructure,thewaytheywouldbeinsideadatabase.
Thiscanonlybedonewithidentifiersgiventoalltheconceptsthat
havetobehandled. TheBibliothèquenationaledeFranceusesper-
sistentidentifiersforwebURIs: the“ARK”6identifiers,whichare
usedtoidentifycataloguerecords,archivalresources,digitalobjects
fromGallica,andauthorityrecords. TheseARKidentifiersarealso
usefulforquotingtheseresources,withacommon“resolver”: for
instance, a digital object7 will also be accessible with a persistent
link.8 InordertogatherinformationaboutWorks,WritersandSub-
jects, data.bnf.frreliesontheauthorityfiles. TheARKidentifiers
thathavebeengiventotheauthorityrecordsarealsousedforthe
pagesindata.bnf.fr,soastobuildreliableURIs,andefficientlinks
betweenthedata.
Use cases for Linked Open Data (LOD)
Conceptsfromauthorityfilesarebasicallyusedforreliableiden-
tification and description, for writers, books, and subjects. Then,
thedifficultyistoproviderelevantlinkstoeditionsofthebooks,
manuscripts,archives,images. Someonlineexamplescanexplain
howdata.bnf.frcopeswiththeseissues. Forinstance,whensearch-
ingforinformationaboutawriterlikeGoldoni,9theuserwillfind
allhismainworkswithpagesgatheringalltheeditionsofthebooks.
Therearelinkstothereferencesoftheeditionsofthecatalogues,to
thedigitalitems,andtothemanuscriptssuchastheletterswhich
6ArchivalResourceKey.
7http://gallica.bnf.fr/ark:/12148/bpt6k134521m.
8http://ark.bnf.fr/ark:/12148/bpt6k134521m.
9http://data.bnf.fr/11905320/carlo_goldoni.
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R.Wenz,Linkedopendatafornewlibraryservices
Goldonireceived. Theauthorityfileshavebeenextracted,andthe
identifiersareusedtomakepersistentlinks,andtoavoidduplicates.
The“Work”pagesarecreatedattheFRBRlevel. Thismeansthat
thebookisdescribedasaconceptandnotasaparticulareditionof
thisWork. Alltheeditionsaregatheredaroundthisconcept. For
instance,onthepageabouttheTrionfibyPetrarcha,10itispossible
tofindalistofthemanuscriptsandoftheprintedbooks,withlinks
toallthedigitalitemswhentheyareavailable. Writersareofcourse
linkedwiththeirworks,withtheassociateddocuments,andwith
otherwriters. Thiskindofinformationisextractedfromthedocu-
mentslinkedtobothofthem. ForawritersuchasLeonardoBruni,
apage11gatherslinkstoalleditions,manuscripts,anddigitalitems.
Thetextshewrote,translated,editedorcommentedareavailable
separately,dependingonhisroleonthedocument. Theusercan
lookforthetranslationshemade,forinstance. Therearealsolinks
tothepagesoftheassociatedwriters,suchasCiceroandAristotle.
Since he was an editor of Cicero, we provide both the references
of the edited books, and a link to the page of Cicero.12 The web
semantictoolsandthereliablelinksenableustobuildpagesaround
thecommonpropertiesandinfernewrelationfromourRDFgraph.
Forinstanceonecanfind:
• data.bnf.frpagesassociatedwiththedate1515;13
• data.bnf.frpagesassociatedwiththedate1789;14
• oralltheauthorswhohavebeenmakingcoins,suchasLouis
XIV.15
10http://data.bnf.fr/11953648/petrarque_les_triomphes.
11http://data.bnf.fr/12027636/bruni_leonardo.
12http://data.bnf.fr/11885977/ciceron.
13http://data.bnf.fr/what-happened/date-1515.
14http://data.bnf.fr/what-happened/date-1789.
15http://data.bnf.fr/vocabulary/roles/r370.
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Data.bnf.fr makes links and publishes web pages containing
already about 2.5 million linked resources. The complete data is
alsodisplayedinRDFandavailablebyclickingontheRDFicon,
atthebottomofthepages,byaddingthefollowingsuffixestothe
URL: NT, N3, RDF-XML, according to the format needed,16 via
contentnegotiation, using aRDFweb browser, fromtheURL, or
bybulkdownloads.17 Asyet(inthesummer2012), thecomplete
availabledatasetis6.3millionRDFtriples,whichisnottomassive
consideringthe2.5millionresources,thankstotheproperlinksthat
avoidustoomuchredundancy. Alltherawdataisalsodisplayedin
RDFandavailablewithanopenlicense. Allowingallkindofuses,
alsoforcommercialpurposes,wasnotobvious.
Why we use an open license for data.bnf.fr.
Legal and technical requirements
Displayinginformationonthewebmeansthattheinstitutionis
responsibleforpublishingdocuments. Legallyspeaking,thelibrary
becomes responsible for the content which is displayed. From a
“marketing”perspective,publishinginformationonthewebisan
incentivetofocusonwhatyoucandobest,andtoletotherstake
care of the things they do better than you, because the users will
prefertousetheirresourcesanyway. Forinstance,librarycatalogues
aredescribingresources,andhandling“concepts”thathavetodo
withdocuments. Thestrengthsandweaknessesarenotthesame,
for instance, as in an encyclopaedia. It would be no use to try to
insertuniversalencyclopaedicknowledgeinsidelibrarycatalogues,
just as it would be useless to provide full lists of documents in-
16Examplehttp://data.bnf.fr/11928016/jules_verne/rdf.xml.
17Fromhttp://data.bnf.fr/semanticweb-en.
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R.Wenz,Linkedopendatafornewlibraryservices
sidegeneralinformationencyclopaedias. Ontheweb,librariesare
bringingalong-timeperspective. Theyhavebeencollectingbooks
forcenturies anddata fordecades. The manpowerprovidedhas
noequalintermsofdescribingbooks. Besides,thedatahasbeen
structuredquiteearly,withinternationalstandardssincethe1960s.
This“descriptivedata”wasnotproducedina“marketing”perspec-
tive: allelementsareaccurate,andmeanttobeinteroperable,even
thoughseveralformatsactuallyexist. Therulesforproducingthe
bibliographic descriptions remained stable, and were strictly fol-
lowedbytrainedcataloguers. Throughseveralformatsforvarious
typesofdocumentssuchasbooks(MARCformats),archives(EAD),
anddigitalresources(DC),thestandardswererespected. Therefore,
theinformationcanbetrustedandprocessedautomatically,even
onalongperiodoftime,andthroughhugeamountsofdata. The
librarycataloguesarealreadymachine-readable,evenifitisnotyet
necessarilywithwebstandards. Displayingthemonthewebwith
webstandardsimpliestouseidentifiers(URIs)sothatpeoplecan
quotetheresources.Ifwewanttoletpeopleusethesewebresources,
wemustprovidereliablelinks. Becausethisisagreatopportunity
toshareourculturalmaterials,theBibliothèquenationaledeFrance
decidedtomakethestructureddatafromdata.bnf.frfreelyavailable,
withanOpenLicence. Openinglibrarydataonthewebisawayto
takepartinthe“opendata”movement,andtogiveaccesstothe
information to the broader public, by using the most recent tech-
nologies. Itisalsoanincentiveforotherstousethismaterialand
togiveaccesstoculture. BymakingtheRDFdatafree,thisproject
alsotakepartoftheinternationalexperimentationsof“LinkedOpen
Data” (LOD) that have popped up among national libraries. As
GildasIllienputsit,«Transformingpre-existingMARCrecordsand
authority vocabularies in RDF triples; starting to implement the
FRBRmodel;playingwiththesemanticwebstandards;building
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