Concept relationship editor: a visual interface to support the assertion of synonymy relationships between taxonomic classifications

An increasingly common approach being taken by taxonomists to define the relationships between taxa in alternative hierarchical classifications is to use a set-based notation which states relationship between two taxa from alternative classifications. Textual recording of these relationships is cumbersome and difficult for taxonomists to manage. While text based GUI tools are beginning to appear which ease the process, these have several limitations. Interactive visual tools offer greater potential to allow taxonomists to explore the taxa in these hierarchies and specify such relationships. This paper describes the Concept Relationship Editor, an interactive visualisation tool designed to support the assertion of relationships between taxonomic classifications. The tool operates using an interactive space-filling adjacency layout which allows users to expand multiple lists of taxa with common parents so they can explore and add relationships between two classifications. Whenever selected lists contain too many items for them to be legible within the restrictions of available screen space the user can alleviate the problem by either operating in ‘lens mode’ or ‘scroll mode’. In ‘lens mode’ the layout is configured so that both of the classifications and all the relationships are completely visible onscreen. Here a fish-eye lens type distortion effect is applied under the cursor to allow taxa names with less assigned space to be made legible. In ‘scroll mode’ the layout assigns sufficient space for the labels of all expanded taxa lists to be legible and scroll bars can be used to navigate across the hierarchy of either classification. While the ‘lens mode’ provides context and allows for more direct comparison of relationships throughout the classifications, ‘scroll mode’ tends to allow for relationships to be added more efficiently between smaller groups of similarly classified taxa.