Metadata Repositories for Interoperable/Shareable Metadata

Records

Records

Repository

Various levels of metadata projects

Application Profile

Schema A

Schema B

Schema C

Benefits of creating shareable metadata

• It will be interoperable, or meaningful when combined with metadata from other sources.

• Your resources are more likely to be found when

pooled together with resources from other providers, rather than not being retrieved by searchers due to inconsistencies or gaps in description.

• It will increase the number of access points for your resources available to end-users.

Source: OAI Best Practices. http://oai-best.comm.nsdl.org/cgi-bin/wiki.pl?PublicTOC

Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH)

• Protocol A protocol is a set of rules defining communication

between systems.– E,g., HTTP, FTP

• HarvestingIn the OAI context, harvesting refers specifically to the gathering together of metadata from a number of distributed repositories into a combined data store.

http://www.openarchives.org/

Illustration of the repository with OAI-PMH structure

Source: Figure 6-4 in Zeng & Qin (2008) Metadata

• Two classes of participants:– Data Providers administer systems that

support the OAI-PMH as a means of exposing metadata; and

– Service Providers use metadata harvested via the OAI-PMH as a basis for building value-added services.

• The protocol mandate a common metadata format: unqualified Dublin Core.– http://www.openarchives.org/OAI/2.0/

openarchivesprotocol.htm

OPAC

image

FTXT

A&I

e-print

Before harvesting: each has a different metadata structure

metadata

OPAC

image

FTXT

A&I

e-print

metadata

OPAC

image

FTXT

A&I

e-print

AuthorTitleAbstractIdentifier

Metadata from many sources can be gathered together in one database, and services can be provided based on this centrally harvested, or "aggregated" data.

An example: NSDL Metadata Repository

Source: NSDL: Core Integration, Technical Overview, 2001

200+ projects: .collections .services.targeted research.pathways.core integration

M etad ataR ep o s ito ry

C o llec tio n C o llec tio n C o llec tio n

S ear c h &D is c o v er y

Ad v an c edD is c o v er y

u s er p ro f iles

Ac c es sM an ag em en t

Users

P ortals

Collection s

Source: NSDL: Core Integration, Technical Overview, 2001

Gazetteer Standard Report Alexandria Digital Library

Reports: Standard Report | Standard XML | Feature Name: Display name: Cold Boiling Lake - Shasta County - California - United States Geographic name: Cold Boiling Lake Variant name: Soda Lake Feature Class: lakes from ADL Feature Type Thesaurus LAKE from GNIS Feature Classes Spatial Reference: Bounding Coordinates: Long: -121.4825 Lat: 40.4561 Long: -121.4825 Lat: 40.4561 Footprints:

Geometry Type: Point Long: -121.4825 Lat: 40.4561 I dentification Code: adlgaz-1-6202475-58 Reference Codes: GNIS Feature ID Number: 254759

<?xml version="1.0" ?> - <gazetteer-standard-report

xmlns="http:/ / www.alexandria.ucsb.edu/ gazetteer" xmlns:gml="http:/ / www.opengis.net/ gml">

<identifier>adlgaz-1-6202475-58</identifier> - <codes>

<code scheme="GNIS Feature ID Number">254759</code> </codes> <place-status>current</place-status> <display-name>Cold Boiling Lake - Shasta County - California - United

States</display-name> - <names>

<name primary="false" status="current">Soda Lake</name> <name primary="true" status="current">Cold Boiling Lake</name>

</names> - <bounding-box>

- <gml:coord> <gml:X>-121.4825</gml:X> <gml:Y>40.4561</gml:Y>

</gml:coord> - <gml:coord>

<gml:X>-121.4825</gml:X> <gml:Y>40.4561</gml:Y>

</gml:coord> </bounding-box> - <footprints>

- <footprint primary="true"> - <gml:Point>

- <gml:coord> <gml:X>-121.4825</gml:X> <gml:Y>40.4561</gml:Y>

</gml:coord> </gml:Point>

</ footprint> </ footprints> - <classes>

<class primary="true" thesaurus="ADL Feature Type Thesaurus">lakes</class>

<class primary="false" thesaurus="GNIS Feature Classes">LAKE</class>

</classes>

ADLstandard report

ADLXML report

ADL record merged into NSDL Metadata Repository More Information

Title [DOQQ, Digital orthophoto quarter quadrangle], Soda Lake South SW , California. Creator United States Geological Survey Creator Analytical Surveys, Inc. Subject Aerial photographs digital raster; California Subject DOQQ; quad; Band interleaved by line; BIL

Description Digital Orthophoto Quarter Quadrangles (black & white) cover the state of California, each quarter quadrangle covering an area 3.75 degrees by 3.75 degrees. Some quadrangles are still in process as of March 2002

Publisher U.S. Geological Survey Western Mapping Center Contributor Alexandria Digital Library

Date 19970204 Date 19940528 Date 19971030 Type Image Type remote -sensing images Type aerial photographs

Format 49189680 bytes Format BIL Format DOQQ Format Digital Orthophotographic Quarter Quadrangle

NSDL enables cross-collection searching

Provides detailed metadata records

Benefits of the OAI approach 1. Material can be accessed more widely; 2. Material can be exploited for purposes different from those

that originally motivated the creation of the repositories; 3. New and improved services can be constructed because of the

possibility of accessing multiple repositories; and 4. There is potential for cost-saving inherent in new models of

the scholarly communication process that could be realized through an open archives approach.

Summarized by Carpenter (2003)

Shareable Metadata in LOD