RDF in the Real World Lessons in Morphing Metadata Juliet L. Hardesty @jlhardes Metadata Analyst, Indiana University Libraries Digital Library Federation Forum 2015, Vancouver, BC
RDF in the Real World
Lessons in Morphing MetadataJuliet L. Hardesty @jlhardes
Metadata Analyst, Indiana University LibrariesDigital Library Federation Forum 2015, Vancouver, BC
The conversation I want to have todayLibraries, archives, and museums deal with metadata A LOT
XML/text files, database tables
Tech we use has figured out how to do things with metadata in those formats
ILS, CMS, digital repositories, flesh & blood programmers \o/ :)
There’s more to this conversationRDF holds a lot of promise
How much is still just promise and how much is reality?
I have my perspective which includes a lot of Fedora 4
This is what I see and what I think we should understand as the library community
Different RDF activities are differentPublish Linked Data
RDF doesn’t have to be Linked Data
Software incorporates RDF for metadata
Digital object management through RDF graphs
Sharing metadata vs digital asset management
Resource Description Framework (RDF)It’s a way to model data:
subject -> predicate -> object .
a thing -> has property -> value of that property .
image has creator person .
<URI for image> <URI for term “creator”> <URI for person> .
REsource Description Framework (RDF)
http://id.loc.gov/authorities/names/no2004088188
http://purl.dlib.indiana.edu/iudl/archives/cushman/P13713
http://purl.org/dc/elements/1.1/creator
has creator
Women in several reds Hilton Hotel. July 14, 1964. Cushman, Charles W., 1896-1972
What RDF is doingDescribing resource (image)
Providing data (relationships and values)
Creating statements
eXtensible Markup Language (XML)<mods>
<identifier>P13713
<location><url>
http://purl.dlib.indiana.../P13713.jpg
<name><namePart>s
Cushman, Charles Weever, 1896-1972
<role><roleTerm>
photographer
.jpg
.xml
What XML is doingDescribing resource (image)
Labeling information (P13713)
Creating a document (record)
Fedora 4Expresses properties about digital objects using RDF
PCDM managing relationships between objects
Portland Common Data Model, Duraspace Github Wiki
RDF properties work unless things get complex
NOT MODS
Valid but complex RDF (statements wrapped inside statements)
subject predicate object1
1subject predicate object;subject predicate object;subject predicate object.
Here’s how things get complex
MODS RDF is currently complex hierarchical RDF
Fedora 4 creates blank nodes for complex RDF
These genres (Academy Award winner and Documentary films) become their own objects in Fedora
Here’s what Fedora 4 does with that
Here’s what’s been happeningGroup within Hydra community working through MODS elements
to find simpler ontology options to express descriptive information (DCTerms, MarcRelator, EDM, SKOS)
MODS and RDF Descriptive Metadata Subgroup - Hydra - DuraSpace Wiki
Steven Anderson at Boston Public Library leading effort
Providing feedback to MODS RDF Ontology group (version 2 in progress!)
PBCore XML + EBUCore RDF = PBUCore (?) RDFXML standard managed by WGBH (Boston again!)
Want to express PBCore XML in RDF to allow for descriptive and technical metadata statements in RDF in Fedora 4
Working with EBUCore to compare PBCore elements, establish which can be expressed with EBUCore classes and properties, and added some additional properties
Expanding expressions in EBUCore and allows PBCore XML to be transformed into RDF
UNLVUNLV started from CONTENTdm
Publishing LOD sets with interface to follow
UNLV Libraries
UCSDStarting with MODS
Complex records so created new data model
Mapping first to local identifiers then figuring out external URIs
Not keeping original MODSUCSD Geisel Library
http://library.ucsd.edu/ontology/dams
Oregon Digital and U AlbertaBringing various collections with various metadata together (silos!)
Wanted to create metadata as Linked Data in new DAMS (Fedora 4/Hydra)
http://oregondigital.org
https://era.library.ualberta.ca
So you have XML for metadata. How do you make it RDF?Develop use cases for why RDF is necessary
What metadata is RDF-ready (expressable as RDF) and how will RDF be used?
If XML doesn’t contain URIs (Linked Data-ready) can it be converted?
If XML standard is available as RDF (DC, DWC), transform XML and see what RDF looks like
Consider if RDF can be used as defined in use cases
So you are an XML standard. How do you make yourself RDF?Develop use cases for why RDF is necessary
Possible path: Create RDF ontology equivalent of XML
DC, DWC, MODS, VRA Core
Possible path: Integrate with an RDF ontology
PBCore XML to EBUCore RDF, with additional properties
Consider if RDF can be used as defined in use cases
Dodge, Mary Elizabeth. 1894. When Life is Young: a collection of verse for boys and girls. [p.] 143. The British Library. https://flic.kr/p/hXAC1A
CHALLENGES FROM XML TO RDFXML schema != RDF ontology
XML encodes information about something (<xml>info</xml>)
RDF statements are the information (info)
Hang in There by jurvetson https://flic.kr/p/7PuQdb
RDF ChallengesRDF ontology or mult RDF ontologies != All your metadata
RDF != Linked Data
NO, It Wasn’t Squirrel Proof !!! by kaceyhttps://flic.kr/p/65uX3J
Bibliography2015. “Descriptive Metadata Call 2015-06-24.” Descriptive Metadata Call 2015-06-24 - Hydra - DuraSpace Wiki. June 24. https://wiki.duraspace.org/display/hydra/Descriptive+Metadata+Call+2015-06-24.
Berners-Lee, Tim. 2009. “Linked Data.” Linked Data - Design Issues. June 18. http://www.w3.org/DesignIssues/LinkedData.html.
Estlund, Karen, and Tom Johnson. 2013. “Link It or Don’t Use It: Transitioning Metadata to Linked Data in Hydra,” July. http://ir.library.oregonstate.edu/xmlui/handle/1957/44856.
Farnel, Sharon. 2015. “Metadata at a Crossroads: Shifting ‘from Strings to Things’ for Hydra North.” presented at the Open Repositories, Indianapolis, Indiana. http://slideplayer.com/slide/5384520/.
Lampert, Cory K., and Silvia B. Southwick. 2013. “Leading to Linking: Introducing Linked Data to Academic Library Digital Collections.” Journal of Library Metadata 13 (2-3): 230–53. doi:10.1080/19386389.2013.826095.
Southwick, Sivlia B. 2015. “A Guide for Transforming Digital Collections Metadata into Linked Data Using Open Source Technologies.” Journal of Library Metadata 15 (1): 1–35.
Thanks!Julie Hardesty, Metadata AnalystIndiana University [email protected]@jlhardes