Digital resources: access methods and levels

Access methods

Descriptions of resources digitized by BnF and accessible via Gallica are based on data from the catalogue général de la BnF and the BnF Archives et Manuscrits catalog.

INTERMARC and EAD records are formatted in Dublin Core simple using mapping tables and recreated in this format within the digital library. 

These Dublin Core records are added to BnF’s OAI-NUM warehouse. The Gallica index, or catalog, is based on the OAI-NUM warehouse and OAI records belonging to partners (publishers, other libraries, etc.). 

Searches in Gallica use the Lucene search engine. Users may search fields in bibliographical records in Dublin Core, as well as, where available, the text of OCR-generated documents – i.e. full text search. 

The OAI-PMH protocol is one of the most efficient responses to the need to externally reference digital resources. It enables digital libraries to export their references to meta-catalogs or specialist portals that provide access to specific collections. This means that resources held in Gallica can also be viewed via other sites.

In addition to the OAI-PMH protocol, other methods of distributing data about digital resources so that they are visible to potential users merit consideration. These include, for example, the following:

• case-by-case descriptions of relevant resources on themed portals
• descriptions on collaborative sites and encyclopedias
  

Access levels

In the physical and analog world, documents are always accessed starting with the largest element and moving through to the smallest; in the digital world, resources can be accessed the other way around.

Bibliographical information in library catalogs does not usually describe elements included within a larger document or set of documents (e.g. articles or issues within a periodical title), unless these elements are so unique or unusual that new access points need to be created for them (e.g. compendia or publications including more than one work in a single volume). 

The basic instrument continues to be the catalog; digital technology makes it possible to add other tools and navigation methods that reflect document granularity.

In the digital world, perceptions of granularity (collections, documents, chapters, articles, dictionary and encyclopedia entries, etc.) are changing, and the various types of elements included within documents are all access points in their own right.

When implementing Gallica, the decision was made to:

• input tables of contents in text format so as to create the structured access points needed to be able to carry out searches and accurately describe resources;
• separate different volumes of periodicals and different issues of daily newspapers which had been bound together.
  

Online periodical websites, such as Cairn, Persée and Australian Newspaper, offer access at article level. Although article access is particularly relevant for this type of document, it poses consistency problems where a digital library contains a wide variety of document types of varying degrees of granularity, as well as requiring significant development. It is, nevertheless, under consideration for Gallica.