This is a survey on graph visualization and navigation techniques, as used in information visualization. Graphs appear in numerous applications such as web browsing, state--transition diagrams, and data structures. The ability to visualize and to navigate in these potentially large, abstract graphs is often a crucial part of an application. Information visualization has specific requirements, which means that this survey approaches the results of traditional graph drawing from a different perspective. Index Terms---Information visualization, graph visualization, graph drawing, navigation, focus+context, fish--eye, clustering. 1

This paper introduces a novel user interface that integrates search and browsing of very large category hierarchies with their associated text collections. A key component is the separate but simultaneous display of the representations of the categories and the retrieved documents. Another key component is the display ofmultiple selected categories simultaneously, complete with their hierarchical context. The prototype implementation uses animation and a three-dimensional graphical workspace to accommodate the category hierarchy and to store intermediate search results. Query specification in this 3D environment is accomplished via a novel method for painting Boolean queries over a combination of category labels and free text. Examples are shown on a collection of medical text.

The literature on information visualization establishes the usability of interfaces with an overview of the information space, but for zoomable user interfaces, results are mixed. We compare zoomable user interfaces with and without an overview to understand the navigation patterns and usability of these interfaces. Thirty-two subjects solved navigation and browsing tasks on two maps. We found no difference between interfaces in subjects ’ ability to solve tasks correctly. Eighty percent of the subjects preferred the interface with an overview, stating that it supported navigation and helped keep track of their position on the map. However, subjects were faster with the interface without an overview when using one of the two maps. We conjecture that this difference was due to the organization of that map in multiple levels, which rendered the overview unnecessary by providing richer navigation cues through semantic zooming. The combination of that map and the interface without an overview also improved subjects ’ recall of objects on the map. Subjects who switched between the overview and the detail windows used more time, suggesting that integration of overview and detail windows adds complexity and requires additional mental and motor effort.

Making effective use of the available display space has long been a fundamental issue in user interface design. We live in a time of rapid advances in available CPU power and memory. However, the common sizes of our computational display spaces have only minimally increased or in some cases, such as hand held devices, actually decreased. In addition, the size and scope of the information spaces we wish to explore are also expanding. Representing vast amounts of information on our relatively small screens has become increasingly problematic and has been associated with problems in navigation, interpretation and recognition. User interface research has proposed several differing presentation approaches to address these problems. These methods create displays that vary considerably, visually and algorithmically. We present a unified framework that provides a way of relating seemingly distinct methods, facilitating the inclusion of more than one presentation method in a single interface. Furthermore, it supports extrapolation between the presentation methods it describes. Of particular interest are the presentation possibilities that exist in the ranges between various distortion presentations, magnified insets and detail-in-context presentations, and between detail-incontext presentations and a full-zooming environment. This unified framework offers a geometric presentation library in which presentation variations are available independently of the mode of graphic representation. The intention is to promote the ease of exploration and experimentation into the use of varied presentation combinations.

This paper examines the usability of the hypertext navigation facilities provided by World Wide Web client applications. A notation is defined to represent the user's navigational acts and the resultant system states. The notation is used to report potential, or `theoretical,' problems in the models of navigation supported by three web client applications. A usability study confirms that these problems emerge in actual use, and demonstrates that incorrect user models of the clients' facilities are common. A usability analysis identifies inadequacies in the clients' interfaces. Motivated by the analysis of usability problems, we propose extensions to the design of WWW client applications. These proposals are demonstrated by our system WebNetwhich uses dynamic graphical overview diagrams to extend the navigational facilities of conventional World Wide Web client applications. Related work on graphical overview diagrams for web navigation is reviewed. 1 Introduction The small...

Desktop conferencing systems are now moving away from strict view-sharing and towards relaxed “what-you-see-iswhat-I-see” (relaxed-WYSIWIS) interfaces, where distributed participants in a real time session can view different parts of a shared visual workspace. As with strict view-sharing, people using relaxed-WYSIWIS require a sense of workspace awareness—the up-to-the-minute knowledge about another person’s interactions with the shared workspace. The problem is deciding how to provide a user with an appropriate level of awareness of what other participants are doing when they are working in different areas of the workspace. In this paper, we propose distortion oriented displays as a novel way of providing this awareness. These displays, which employ magnification lenses and fisheye view techniques, show global context and local detail within a single window, providing both peripheral and detailed awareness of other participants ’ actions. Three prototypes are presented as examples of groupware distortion-oriented displays: the fisheye text viewer, the offset lens, and the head-up lens.

Networks have remained a challenge for information visualization designers because of the complex issues of node and link layout coupled with the rich set of tasks that users present. This paper offers a strategy based on two principles: (1) layouts are based on user-defined semantic substrates, which are non-overlapping regions in which node placement is based on node attributes, (2) users interactively adjust sliders to control link visibility to limit clutter and thus ensure comprehensibility of source and destination. Scalability is further facilitated by user control of which nodes are visible. We illustrate our semantic substrates approach as implemented in NVSS 1.0 with legal precedent data for up to 1122 court cases in three regions with 7645 legal citations.

We have designed two interfaces to support one-handed thumb use for PDAs and cell phones. Both use Scalable User Interface (ScUI) techniques to support multiple devices with different resolutions and aspect ratios. The designs use variations of zooming interface techniques to provide multiple views of application data: AppLens uses tabular fisheye to access nine applications, while LaunchTile uses pure zoom to access thirty-six applications. Two sets of thumb gestures represent different philosophies for one-handed interaction. We conducted two studies to evaluate our designs. The first study explored whether users could learn and execute the AppLens gesture set with only minimal training. Participants performed more accurately and efficiently using semantic gestures for directional navigation than abstract gestures for object interaction. A second study gathered user reactions to each interface, as well as comparative preferences. With minimal exposure to each design, most users favored the tabular fisheye interface.

Interactive selection is a critical component in exploratory visualization, allowing users to isolate subsets of the displayed information for highlighting, deleting, analysis, or focussed investigation. Brushing, a popular method for implementing the selection process, has traditionally been performed in either screen space or data space. In this paper, we introduce the concept of a structure-based brush, which can be used to perform selection in hierarchically structured data sets. Our structure-based brush allows users to navigate hierarchies by specifying focal extents and level-of-detail on a visual representation of the structure. Proximity-based coloring, which maps similar colors to data that are closely related within the structure, helps convey both structural relationships and anomalies. We describe the design and implementation of our structure-based brushing tool. We also validate its usefulness using two distinct hierarchical visualization techniques, namely hierarchical ...

Visualizations of software changes are presented that complement existing visualizations of software structure. The principal metaphors are matrix views, cityscapes, bar and pie charts, data sheets and networks. Linked by selection mechanisms, multiple views are combined to form perspectives that both enable discovery of high-level structure in software change data and allow effective access to details of those data. Use of the views and perspectives is illustrated in two important contexts: understanding software change by exploration of software change data and management of software development.