What is Visual Metaphors

This chapter introduces a new category of digital library user interfaces called metadata-enhanced visual interfaces. Drawing on the earlier information retrieval visual interfaces that have made use of thesauri, this chapter will review and analyze metadata-enhanced visual interfaces to digital libraries based on two key variables, namely metadata elements used for visualization purposes and visual metaphors incorporated into the user interfaces. The aim of this study is to inform the design of visual interfaces for digital libraries through bringing together issues that have roots in such communities as information retrieval, digital libraries, human-computer interaction, and metadata. The findings of this study provide design ideas and implications for digital library interface design in terms of the various metadata-based information search and retrieval features for visualization purposes.