The European Library Automation Group, brings together once a year people involved in library automation in the leadingEuropean libraries and information centres. The organization counts 450 members in 27 countries all over Europe. Last years over 100 colleagues attended the seminars.

The meetings aim at in depth discussions of particular library automation topics and at the promotion of informal exchange ofideas and experience. The topics covered are technical and meant for participants with computing background.

26 - 28 April 2006 Bucharest, Romania

Workshop WS2: The European Metadata Registry – Influence Interoperability - Discussion guidelines 

Oliver Greening, Consultant, Petersfield, United Kingdom (e. ogreening@hotmail.co.uk) 

Julie Verleyen, Technical Assitant, The European Library, The Netherlands (e. Julie.Verleyen@kb.nl) 

Why a European Metadata Registry? 

Digital Libraries, one of the flagship initiatives of i2010 a European Information Society for growth and jobs, aims at making European information resources easier and more interesting to use in an online environment. The strategy for its development is in place and the Commission issued the following press release: 

“The consultation results have helped the Commission to further define the practical set-up of the European Digital Library, which will provide a highly visible, multilingual access point, dedicated to the digital resources of Europe’s cultural institutions. It will build upon the TEL-infrastructure, currently the gateway to the catalogue records of collections in a number of national libraries, which also gives access to a range of digitised resources of the participating libraries. 

 (source: European Commission, Brussels, 02 March 2006 IP/06/253) 

Various organisational structures and tools will be needed to make this a reality. As usual one of the most important requirements is  interoperability - there is a need to create systems that are mutually compatible. The many cultural institutions have different ways of digitising and extracting data. We need to find ways to make this data useful in the short to medium term and to standardise it in the longer term.  A European Metadata Registry (EMR) could be a functional tool that can be developed to support this important process. 

Against this strategic background this workshop will attempt to assess if there is a need for an EMR, if this need is short or long term (given emerging technologies) and if so, what should it be and will ELAG recommend the creation of an EMR and why? Attendees will then try to reach an agreed definition of a EMR and a set of responses to the fundamental issues outlined below. 

What is a European Metadata Registry? 

A metadata registry can be defined as “an application that provides services based on information about metadata vocabularies, the component terms that make up those vocabularies, and the relationships between terms” (Baker et al, 2003). These services could allow users to access: 

  • Term definitions;
  • Encoding schemes used;
  • Relationships with other terms;
  • Where terms have been used, i.e. in which application profiles;
  • Documentation on the issues that were encountered when the term was created/implemented;
  • Register of application profiles;
  • Recommended application profiles for different material types;
  • Technology to support the controlled evolution of the application profiles (including audit trail of changes);
  • Procedure to support the controlled evolution of the application profiles;
  • Facility to search for metadata terms. 

In the context of the European Digial Library a EMR could, for example, deliver consultation services that provide mappings between different standards used to describe digital resources accessible through the European Digital Library (see Figure 1). However, a metadata registry could also be broader and comprise the following elements: 

  1. Schema: data in the form of standards, application profiles and vocabularies;
  2. Structures: models or set of terms (including instructions for understanding and documenting schema);
  3. Services/tools: mappings, inferencing, translations, versioning;
  4. Relations: descriptions of relationships between connecting registries. 

So if the EMR is really needed, what should it be, what is its scope, where should the boundary of a EMR be drawn and what should its components be?










Figure 1: Potential role of a European Metadata Registry within a conceptual model
of the European Digital Library

Who is going to benefit from a European Metadata Registry?

The stakeholders who could benefit from a EMR are likely to be diverse, each with their specific needs. The four scenarios summarised below provide examples of potential use cases, but can stakeholder groups and their needs be defined and characterised? can the potential benefits be qualified? 

Scenario 1:

I am a researcher in egyptology interested in genealogy of Pharaohs during the 18th dynasty. I want to find the following materials:

  • historic books/articles about Toutankhamon and his relatives;
  • pictures of hieroglyphs found in 18th dynasty Pharaohs graves;
  • DNA analysis results attesting blood lineages;
  • etc… 

Where do I need to search?

  • historic genealogy databases/biology databases;
  • museums;
  • libraries. 

Scenario 2:

I am a journalist writing an article about François Mitterand’s life. I want to find the following materials:

  • records of his military life during WWII;
  • articles in newspapers, videos, radio interviews during his political career published/broadcasted in France and in other countries;
  • websites 

Where do I need to search?

  • archives;
  • libraries;
  • internet;
  • history museums. 

Scenario 3:

I am a developer building a portal to search the databases and websites of museums, libraries, archives, publishers, etc. I need to know the format and schemes of the metadata (if available), the mapping between the different schemes, the controlled vocabularies existing for interface presentation. The search form can be adapted according to the metadata terms available. 

Scenario 4:

I am a librarian collaborating with museums and archives to build a website about Picasso: books about Picasso, letters written by/to Picasso, pictures of works of Picasso, articles of critics about Picasso’s work, photographs of Picasso/his models/his family/his studio. The website wilI present these different materials with the possibility to link the ones with the others. 

What are the challenges & issues in developing a European Metadata Registry? 

Some of the fundamental challenges and issues that could be faced in the development of a EMR are outlined below, but what development approach should be adopted and who should be involved? For example, as a first step a ‘registry’ of all relevant schemas could be developed, then perhaps tools for schema crosswalks, inferencing and translations. Perhaps it is necessary to fully understand the needs of users? 

Data models

Different metadata standards are based on different conceptual models/frameworks. The terms defined within a specific standard are defined and deployed within that specific conceptual model. If the scope of the registry is to extend across metadata terms based on different conceptual models, then this considerably increases the level of complexity.


Assuming that the first step in establishing a EMR is the development of a registry of relevant schemas, there is an immediate issue of centralised vs. distributed registration. Different metadata standards, terms and schemas are developed and maintained by different organisations /stakeholder groups. Instead of re-inventing and duplicating existing terms/schemas in a centralised registry, a EMR has an option to dynamically link to schemas that are maintained outside the registry. The schema owner would be responsible for its schema maintenance. The process of schema registration, whether held centrally or distributed, could introduce Intellectual Property Right issues. The concept of a registry assumes that schema owners are happy to disclose the details of their schemas. 


Once established and available for use the realisation of benefits from a EMR is dependent on schema registrations by stakeholders and the level of schema use. Tthe sustainability of a EMR and hence the level of success in encouraging interoperability requires motivated/incentivised stakeholders. To motivate/incentivise stakeholders the benefits of participation need to be clearly defined and communicated. 

Recommended background reading: 

Digital Libraries


ISO/IEC 11179, Information Technology -- Metadata Registries (MDR)

Specifies basic attributes of the kind and quality of metadata necessary to describe other data, and it specifies the management and administration of that metadata in a metadata registry.

Baker, T., Blanchi, C. et al. Principles of Metadata Registries. White Paper of DELOS Registries Working Group (2003)

An attempt by researchers from different backgrounds and perspectives on the metadata world to articulate a shared set of principles underlying the construction of metadata registries.

Rachel Heery, Pete Johnston, Dave Beckett and Damian Steer. "The MEG Registry and SCART: complementary tools for creation, discovery and re-use of metadata schemas". Proceedings of the International Conference on Dublin Core and Metadata for e-Communities 2002, pp 63-69

An account of the schema creation tool developed as part of the MEG Registry project.

Rachel Heery, Pete Johnston, Csaba Fülöp and András Micsik. "Metadata schema registries in the partially Semantic Web: the CORES experience". Proceedings of the 2003 Dublin Core Conference: Supporting Communities of Discourse and Practice - Metadata Research and Applications, Seattle, Wa., USA, 28 September - 2 October 2003

Reflections on the experiences of implementing the CORES metadata schema registry.


SchemaWeb Registry

SchemaWeb is a repository for RDF schemas expressed in the RDFS, OWL and DAML+OIL schema languages. SchemaWeb gathers information about schemas published on the web, and merges the RDF statements from all the schemas registered in the directory into an RDF triples store. SchemaWeb provides browse/search interfaces for human users, and REST and SOAP query interfaces for applications.

DCMI Registry

The Dublin Core Metadata Initiative's Metadata Registry is an application designed to provide users and applications an authoritative source of information about the Dublin Core element set and related vocabularies.

The European Library Metadata Registry (TELMR)

Information Environment Metadata Schema Registry (IEMSR)


Metadata for Education Group (MEG) Registry


CORES Registry


SCHEMAS Registry


DESIRE Registry