Usability of Information Visualization: Reading and Interaction Processes

Thematic maps in the context of information retrieval are tools that graphically present documents and characterising terms. We investigated the usefulness of thematic maps in a laboratory experiment comparing a thematic map with a command language interface. Six subjects solved eight search tasks producing ten hours of logged and tape-recorded data. The experiment revealed no improvement in the quality of the documents retrieved when using a thematic map. A majority of the subjects considered the thematic map pleasant to use and thought that useful information was found on the map. However, searching took longer time using the thematic map compared with the boolean interface. Several subjects occasionally misinterpreted the structure and content of the map. The common expectation that thematic maps improve information retrieval lacks empirical underpinning and is in the present study only weakly confirmed.