fedora migration considerations

Fedora migration considerations

Juliet L. HardestyMetadata Analyst, Indiana University

Open Repositories, June 15, 2016

Fedora 3 diagram key

Repository object

Structural metadata datastream

Descriptive metadata datastream

Other metadata datastream

Indiana University President's Office records, 1937-1962. Subject files, 1937-1962. Aeons, Board of, 1939-1940.

Fedora 3 - documents

VAA8877-06169 Fedora DC

RELS-EXT METS

VAA8877-U-03624 Fedora DC

RELS-EXT PDF

VAA8877-U-03624-001Fedora

DCRELS-EXT MASTER

Derivatives

MASTER-MIX

Folder

Document in folder

Page in document

isMemberOfCollection

isPartOf

isPartOf

Portable soft drink stand at Bowling Green

Fedora 3 - images

P02668 Fedora DC

RELS-EXT METSPURL

Redirect

isMemberOfCollection

DCMODS

Image

[Program, 2013-2014, no. 117]

Fedora 3 – time-based media

avalon:22187Fedora

DCRELS-EXT MODSRIGHTS

SECTIONS TECH/DISPLAY

WORKFLOW

Fedora DC

RELS-EXT

STRUCTURE MATTERHORN

avalon:22191

Fedora DC

RELS-EXT

STRUCTURE MATTERHORN

Item

CD 1 CD 2

avalon:22189

isMemberOfCollection

TECH/DISPLAY

TECH/DISPLAY

isPartOf

isPartOf

Focusing on Fedora 3 structure

• RELS-EXT defines structure going up• METS or special datastreams required to

define structure going down• All in XML as datastreams on objects that

connect together down to the digital file

https://github.com/duraspace/pcdm/wiki

PortlandCommonDataModel

Document example in PCDM

Wilcox, David and Andrew Woods. “Hands-On: Seeing Fedora 4 Firsthand.” Fedora 4 Training Workshop. Open Repositories 2015.

METS: fileSec

METS: structMap

VAA8877-06169 VAA8877-U-03626 VAA8877-U-03626-page1

filesdocuments pages

VAA8877-U-03626Proxy VAA8877-U-03626-page1Proxythumb.jpg

screen.jpg

large.jpg

pcdm:hasMember

pcdm:hasMember

Fedora 4 structure diagram

http://localhost:8080/fcrepo/rest/VAA8877-U-03625/pages/VAA8877-U-03625-page1Proxy

METS as PCDM in Fedora – SPARQL query

select DISTINCT ?document ?firstPage ?nextPage where {{ <http://localhost:8080/fcrepo/rest/VAA8877-06169> pcdm:hasMember ?document . ?document iana:first ?firstPageProxy . ?firstPageProxy ore:proxyFor ?firstPage . } union { <http://localhost:8080/fcrepo/rest/VAA8877-06169> pcdm:hasMember+ ?page . ?page pcdm:hasFile ?f . ?f ebucore:hasMimeType "image/jpeg"^^xsd:string . ?pageProxy ore:proxyFor ?page . ?pageProxy iana:next ?nextPageProxy . ?nextPageProxy ore:proxyFor ?nextPage . }}

SPARQL query results for structure of folder VAA8877-06169

Transforming METS to PCDM

• Consider structure for collections using METS• fileSec and structMap– @GROUPID, @ID, @FILEID (unique identifiers

from both sections) in combination with <div> structure within structMap can point to grouping and ordering structure for objects

• Migrating easier if identifiers brought over

Considerations for structural metadata

• RELS-EXT in Fedora 3 migrated to Fedora 4• Other structure datastreams are on you to

map• METS – possible to map programmatically but

maybe not in a standard way

Descriptive Metadata - IU

MODS

Fedora 4 options for descriptive metadata: Option 1

• Migration tools– migration-utils– fedora-migrate gem

Neither really takes advantage of Fedora 4/external triplestoreunless original is already RDF; fedora-migrate requires Hydra

Available now, keeps all metadata, nothing lost; can have RDF statements on object if already in RDF (fedora-migrate)

Descriptive metadata to Fedora 4: Option 2

• Map only simple statements to RDF– Minimal descriptive metadata (title, date) or

descriptive metadata indexed for discovery (title, date, creator, type, subject, genre, language)

– Use ontologies that allow for simple statements

X X XNot MODSRDF

Descriptive metadata to Fedora 4: Option 2

• Map only simple statements to RDF– Minimal descriptive metadata (title, date) or

descriptive metadata indexed for discovery (title, date, creator, type, subject, genre, language)

– Use ontologies that allow for simple statements

Not all metadata is in RDF; changes in ontologies/standards might not be 1:1 match with original

Creates RDF statements in Fedora 4/external triplestore; great option if metadata is DC or other non-hierarchical standard

Descriptive metadata to Fedora 4: Option 3

• Map complex/hierarchical information into external triplestore– All RDF statements (simple and complex) go into

external triplestore but only simple statements are on Fedora 4 object

Cushman photograph – Fedora 4

Cushman photograph – external triplestore

Descriptive metadata to Fedora 4: Option 3

• Map complex/hierarchical information into external triplestore– All RDF statements (simple and complex) go into

external triplestore but only simple statements are on Fedora 4 object

Separates metadata between repository and triplestore,problematic if original metadata not kept in repository

More/all metadata available as RDF; updates easier to managethrough triplestore/Fedora 4 functionality

Descriptive metadata to Fedora 4: Almost Option 4

• MODS “unofficial standard” mapping to RDF– MODS and RDF Group’s mapping/transformation

scenario (http://mods2rdf.xyz/) – Available as conversion code to see MODS mapped

into Fedora 4

Work in progress (not always up, transforming few elements); you might not agree with suggested mappings

Available now to try; might offer standard way to transform MODS similarly across institutions

Considerations for descriptive metadata

• Current state of descriptive metadata• Management needs of Fedora 4• Transform to RDF statements or also to Linked

Data• Decision: keep original descriptive metadata

or not?– At IU, keep original descriptive metadata (for full

item view)

Thank you!

• Julie Hardesty• jlhardes@iu.edu• @jlhardes