Citation: Shiri, A. 2008. Metadata-enhanced visual interfaces to digital libraries. Journal of Information Science, 34 (6), 763-775. Available from: http://jis.sagepub.com/content/34/6/763.full.pdf+html [doi: 10.1177/0165551507087711]
Abstract:Information visualization offers a variety of ways in which digital library collections can be represented and shown to the user. Metadata has been used
to enhance visual user interfaces to digital libraries. This paper reports on a study conducted to investigate and analyze a specific category of digital library visual interface that supports information seeking, exploration and retrieval based on metadata representations, namely metadata-enhanced visual interfaces. This study examined 21 metadata-enhanced digital library visual interfaces from the following perspectives: (a)
information access and retrieval features; (b) metadata elements; (c) visualization techniques and metaphors. The results demonstrated that the combined use of visualization techniques and metaphors is becoming increasingly prevalent as a design strategy to support users’ information exploration. The results also suggest
that visual interfaces enhanced with metadata are becoming more widespread to provide a richer representation of digital collections.
Research Questions: 1) In what ways have designers of visual interfaces for digital libraries utilized metadata elements to support users in their search process and interaction experience. 2) Which information visualization techniques and metaphors are most popular.
Methodology: The study examined digital library visual interfaces from the following perspectives:
• information access and retrieval features supported;
• metadata elements used;
• visualization techniques and metaphors utilized.
Seven measures were used to analyze the interfaces. These were: visualization techniques, visual metaphor, metadata elements used, focus on query formulation and modification visualization, focus on search results visualization, focus on collection representation visualization, and relevance visualization. 21 visual interfaces were examined. Nine interfaces were developed in the 1990s and the remaining 12 were developed
in the 2000s.
Results: A variety of visualization techniques have been used within these interfaces, with two-dimensional visualization as a dominant technique. Other visualization techniques used included three-dimensional, multidimensional, tree structures, network, and temporal. Use of 3D and multidimensional visualization techniques increased substantially in the 2000s as did the combined use of visualization techniques.
While all of the user interfaces have taken advantage of metadata in their design, their focus is on visualization techniques and information retrieval. Therefore, they do not provide detailed information about the type of metadata standards or formats that they have used. Interfaces examined in this study have made use of different
types of metadata elements. Except for LibViewer, which makes use of the Dublin Core Metadata standard, none of the interfaces provide any indication of their metadata formats or standards. A wide range of metadata elements have been incorporated into the visual interfaces. These elements can be generally categorized as follows:
• Thesauri and controlled vocabularies as key source of subject metadata.
• Item-level and collection-level metadata.
• Well known metadata formats such as Dublin Core.
• Educational, statistical and geographic metadata.
Discussion & Conlcusions: In order to maximize the benefit of metadata for interface design, future research should explore the ways in which metadata can be used to support all stages of the search process, namely query formulation, reformulation, expansion and results presentation. For instance, subject metadata, taken from such sources as thesauri and taxonomies, can provide users with additional search terms to expand or reformulate a particular query. As was found in this study, metadata contributes to the rich representation of the collection and items in visual interfaces. One approach to this type of
design would be to have metadata presented to the user along with a subset of the collection to provide context.