The Community for Technology Leaders
Green Image
Three papers in this issue of TVCG are expanded versions of ones presented at InfoVis 2004. These examples of the cutting edge of information visualization research show the maturing of the field, using novel methods for designing, developing, and evaluating tools that help users solve real problems on large and complex data sets, rather than just creating interesting displays.
"Knowledge Precepts for Design and Evaluation of Information Visualizations" by Robert A. Amar and John T. Stasko won the InfoVis 2004 Best Paper Award. In this paper, the authors argue that efforts to date to design effective visualization tools often fail because they concentrate mostly on presenting data, as opposed to supporting analysis. Limitations of existing systems are grouped into two gaps in the analysis process; the Worldview Gap consists of the difference between what is shown and what is needed to make decisions, while the Rationale Gap consists of the difference between relationships viewed and the certainty and utility of the relationship. Analysis of existing tools using this framework reveals many ways in which techniques can be improved to better support high-level analysis.
"An Insight-Based Methodology for Evaluating Bioinformatics Visualizations" by Purvi Saraiya, Chris North, and Karen Duca presents a novel method for assessing and comparing the effectiveness of visualization tools, namely, the number and type of insights discovered. The authors define an insight as a unit of discovery and identify several attributes and categories of insights. They then report the results from controlled experiments used to evaluate five software tools for visual exploration of microarray data. The results shed many insights into what makes a visualization tool effective.
"Topological Fisheye Views for Visualizing Large Graphs" by Emden R. Gansner, Yehuda Koren, and Stephen North describes a multiresolution technique for the effective and efficient visualization of graphs with thousands or even millions of nodes. They present an elegant method for graph hierarchy generation that preserves topological relations that can be computed in seconds even on graphs of a million nodes and links. A focal point is then specified and the resolution of subgraphs displayed depends on their distance from the focus. Methods to animate the movement of the focus, and the corresponding change in subgraph resolution, help maintain context.
Matthew O. Ward
Tamara Munzner
Guest Editors

    M.O. Ward is with the Computer Science Department, Worcester Polytechnic Institute, 100 Institute Rd., Worcester, MA 01609.


    T. Munzner is with the Department of Computer Science, University of British Columbia, 2366 Main Mall, Vancouver BC V6T 1Z4 Canada.


For information on obtaining reprints of this article, please send e-mail to:

Matthew O. Ward received the PhD degree in computer science from the University of Connecticut in 1981. He is currently a full professor in the Computer Science Department at Worcester Polytechnic Institute (WPI). He was employed as a member of the technical staff in the Robotics and Computer Systems Research Laboratory at AT&T Bell Laboratories between 1980 and 1984 and as a research scientist at Skantek Corporation until 1986, when he joined the faculty at WPI. His research interests include data and information visualization, visual languages, and scientific data management and analysis. He has authored or coauthored more than 70 publications in these areas and is actively involved in the development of a text book in the area of data visualization. He is the primary architect on several public-domain software packages for multivariate data visualization and exploration, including XmdvTool, MAVIS, and SpiralGlyphics.

Tamara Munzner received the PhD degree from Stanford University in 2000. She has been an assistant professor in the University of British Columbia Department of Computer Science since 2002. Her current research interests are information visualization, graph drawing, dimensionality reduction, and interactive computer graphics. She was a research scientist from 2000 to 2002 at the Compaq Systems Research Center in California. She was on the technical staff of The Geometry Center, a mathematical visualization research group at the University of Minnesota, from 1991 to 1995.
83 ms
(Ver )