# Presentation: 391012

## METS: Metadata Encoding and Transmission Standard

- Richard Gartner
- Oxford University Library Services
- rg@bodley.ox.ac.uk

## The digital library: a status report 

-  Digitisation technology now well 	        established and well-understood
-  Standards for digitisation processes have     settled down and are widely recognised
-  Still a disparity in approaches to metadata   - no MARC standard for digital library

## Approaches to metadata - some examples from Oxford

-  Ad-hoc databases: eg. *Allegro*
* *SGML: including:-
-  TEI alone
-  TEI + EAD
-  Ad-hoc DTDs
-  Proprietary databases: eg *Olive*

## The lack of a  standard: what it mean for the digital library

- poor cross-searching
- limited interchange facilities
- metadata tied to proprietary packages
- consequent obsolescence and costs of conversion

## What is needed?

-  A standard for metadata content :          analogous to AACR2
-  A standardised framework for holding   and exchanging metadata : analogous    to the MARC  record

## Three types of metadata(defined by DLF)

**Descriptive**
**Administrative**
**Structural**

-  Information about intellectual content
-  (analogous to standard catalogue record)

-  Information for handling, maintenance
-   and archiving of object

-  Description of internal structure of object

## METS: Metadata Encoding and Transmission Standard

- Produced by Library of Congress Standards Office and Digital Library Federation
- Provides **framework **for holding all types of metadata for digital object
- Written in XML
- Does not prescribe **content **of metadata, but recommends a number of schemes for this

## Why XML?

- An ISO standard, not dependent on any given application
- Interchangeability with other applications
- Handles structural metadata easily
- Easy to integrate cataloguing information with text transcription, images etc.

## Features of a METS file

- All metadata  (descriptive, administrative and structural) encoded in single document
- Each type is held in a separate section, linked  by identifiers
- All metadata and external data (eg. images, text, video) is either referenced from METS file or can be held internally

## The structure of a METS file

## Slide 11

## The structure of a METS file

## Slide 13

## The structure of a METS file

## Slide 15

## The structure of a METS file

## Slide 17

## Descriptive and administrative metadata

-  Descriptive and administrative metadata      may be handled in two ways:-
- embedding directly within the METS 	     file within an <mdWrap> element (with   any namespace)
- 	being held in an external file and                  referenced from the METS file using an       <mdRef> element

## The structure of a METS file

## Slide 20

## The structure of a METS file

## Slide 22

## IDs and METS

-  All compontents of a METS file need to     be identified with a logical (and easily        generated) sets of identifiers

## What to put in a METS file?

-  METS does not prescribe the content (particularly the                descriptive metadata) which it can contain

-   However, the METS board does endorse some schemas as              recommended:-Descriptive Metadata
- 	Dublin Core
- 	MODS (Metadata Object Description Schema)
- 	MARCXML MARC 21 Schema (MARCXML) Administrative Metadata
- 	Schema for Technical Metadata for Text (NYU)
- 	Library of Congress Audio-Visual Prototyping Project
- 	NISO Technical Metadata for Digital Still Images
- 	Schema for Rights Declaration

## METS Profiles

-  METS is very flexible in its application – there        are multiple ways of encoding everything:-
- 	metadata and data can be embedded or                     referenced
- 	any scheme can be used for this metadata
- 	file inventory can be organised in multiple ways      (by referenced 	object, by type of file etc)
-   This all reduces interchangeability of METS            records.

## METS Profiles

-  This can be countered to some extent by METS       Profiles:-
-   XML documents describing application of METS    in a given project/institution
- 	follows METS Profile schema and each profile 	has to validate against it
- 	registered with central repository at Library of         Congress
-  But does not allow automated cross-mapping of       METS files: this has to be explored

## METS in action

**Oxford Digital Library:-**
- 	a collection of collections of material held in Oxford 	libraries
- 	METS files generated by automated webform-based 	cataloguing system
- 	descriptive metadata qualified Dublin Core 				following strict cataloguing guidelines (aimed to 		map to AACR2) – moving 	to MODS being 			investigated
- 	METS files easily converted to formats of digital 		library systems (currently investigating Greenstone)

## Conclusions

-  METS will undoubtedly be the central format for   digital library metadata: the MARC of the DL          world**Issues to be addressed:-**
** **standardization of metadata content and 			     application (an AACR2 to MET's MARC)
-  take-up by vendors: lobbying by major bodies
-  more tools needed for creation and exploitation of   METS records
-  critical mass

## Further information

**www.loc.gov/standards/mets**
**www.jisc.ac.uk/index.cfm?name=techwatch_report_0205**