GTAA Web Browser
The application provides a way to search for and browse through the Dutch GTAA (Common Thesaurus for Audiovisual Archives) thesaurus.
This vocabulary, used by the Dutch national public Audiovisual and radio archives for its documentation process, covers a wide range of topics, as it is meant to describe anything that can be broadcasted on TV or radio. It contains approximately 160.000 terms, divided in 6 disjoint facets: Keywords, Locations, Person Names, Organization-Group-Other Names, Maker Names and Genres.
The thesaurus mainly uses constructs from the ISO 2788 standard, like Broader Term, Narrower Term, Related Term and Scope Notes. Terms from all facets of the GTAA may have Related Terms, Use/Use for and Scope Notes, but only Keywords and Genres can also have a Broader Term/Narrower Term relations, organizing them into a set of hierarchies. Additionally to these standard features, Keywords terms are thematically classified in 88 subcategories of 16 top Categories.
Preferred Term: ambachten (crafts) Related terms: ondernemingen (ventures) , beroepen (professions), artistieke beroepen (artistic professions) Broader Term: beroepen (professions) Narrower terms: boekbinders (bookbinders), bouwvakkers (building workers), glasblazers (glassblowers) ... Scope Note: niet voor afzonderlijke ambachten maar alleen als verzamelbegrip, bijv. voor (markten van) oude ambachten (not for specific crafts, only in general meaning, e.g. (markets of) old crafts) Categories: 05 economie (economy), 09 techniek (technique)
The browser (http://ems01.mpi.nl:8080/GTAABrowser) gives access to terms from a selection of facets. It gives the possibility to access all terms of a given Category, browse through the different elements of the thesaurus displayed as a tree and to refine a search by combining different categories.
For example, if a user selects the Category Military Issues, the terms related to Military Issues are displayed, and other overlapping categories are proposed for narrowing down the number of terms (this numbers are shown to the user). If the user selects also Traffic and Transportation, he will get the list of military vehicles in the thesaurus. He can narrow down his query even further by selecting Vessels, in which case the list is narrowed down to military vessels. The number of terms to be displayed can thus be narrowed down to a dozen by two or three clicks.
All the relationships in the thesaurus are proposed as hyperlinks to navigate its content. This includes pre-computed inter-facets links that are not part of the ISO standard, though allowed by the GTAA data model. For example, one can link a "King" in the Person facet to the general subject "Kings" and the country which this King rules.
Other information (related terms, non preferred terms and Scope notes) for terms is displayed as well. Especially when a facet has no hierarchical structure, an alphabetical access (using spell checking and computed synonym tables) can be granted to the thesaurus preferred terms.
The Browser is accessible across the Web, and is implemented as a web application that can retrieve thesaurus data from an extensible set of data sources, including a the primary relational database one or a research-oriented RDF/OWL one. This will allow for getting updated versions of the thesaurus, via an XML export of the documentation system converted into SKOS. The application shall not deal therefore with the changes that are currently made manually by an expert committee, even though this current process lacks useful features such as generation of unique identifiers for Preferred terms, checking that hierarchical or associative relationships only occur between Preferred terms, or making a concept-based view of the thesaurus instead of a term-based one.