Never before in history has data been generated at such high volumes as it is today. Exploring and analyzing the vast volumes of data is becoming increasingly difficult. Information visualization and visual data mining can help to deal with the flood of information. The advantage of visual data exploration is that the user is directly involved in the data mining process. There are a large number of information visualization techniques which have been developed over the last decade to support the exploration of large data sets. In this paper, we propose a classification of information visualization and visual data mining techniques which is based on the data type to be visualized, the visualization technique, and the interaction and distortion technique. We exemplify the classification using a few examples, most of them referring to techniques and systems presented in this special section.

Direct manipulation user interfaces have proven their worth over two decades, but they are still in their youth. Dramatic opportunities exist to develop direct manipulation programming to create end-user programming tools, dynamic queries to perform information search in large databases, and information visualization to support network database browsing. Direct manipulation depends on visual representation of the objects and actions of interest, physical actions or pointing instead of complex syntax, and rapid incremental reversible operations whose effect on the object of interest is immediately visible. This strategy can lead to user interfaces that are comprehensible, predictable and controllable. Direct manipulation interfaces are seen as more likely candidates to influence advanced user interfaces than adaptive, autonomous, intelligent agents. User control and responsibility are highly desirable.

In previous work, researchers have attempted to construct taxonomies of information visualization techniques by examining the data domains that are compatible with these techniques. This is useful because implementers can quickly identify various techniques that can be applied to their domain of interest. However, these taxonomies do not help the implementers understand how to apply and implement these techniques. In this paper, we will extend and then propose a new way to taxonomize information visualization techniques by using the Data State Model [Chi98]. In fact, as the taxonomic analysis in this paper will show, many of the techniques share similar operating steps that can easily be reused. The paper shows that the Data State Model not only helps researchers understand the space of design, but also helps implementers understand how information visualization techniques can be applied more broadly. Keywords Information Visualization, Data State Model, Reference Model, Taxonomy, Te...

Research on information visualization has reached the place where a number of successful point designs have been proposed and a number of techniques of been discovered. It is now appropriate to begin to describe and analyze portions of the design space so as to understand the differences among designs and to suggest new possibilities. This paper proposes an organization of the information visualization literature and illustrates it with a series of examples. The result is a framework for designing new visualizations and augmenting existing designs.

Therapy planning plays an increasingly important role in the everyday work of physicians. Clinical protocols

Today’s system administrators, burdened by rapidly increasing network activity, must quickly perceive the security state of their networks, but they often have only text-based tools to work with. These tools often provide no overview that would help users grasp the big-picture. Our interviews with administrators have revealed that they need visualization tools. Thus we present VISUAL (Visual Information Security Utility for Administration Live), a network security visualization tool that allows users to perceive communications patterns between their home (or internal) networks and external hosts. VISUAL is part of our Network Eye security visualization architecture, also described in this paper. We have designed and tested a new computer security visualization that gives a quick overview of current and recent communication patterns in the monitored network to the users. Many tools can detect and show fan-out and fan-in, but VISUAL shows network events graphically, in context. Visualization helps users comprehend the intensity of network events more intuitively than text-based tools can. VI-SUAL provides insight for networks with up to 2,500 home hosts and 10,000 external hosts, shows the relative activity of hosts, displays them in a constant relative position, and reveals the ports and protocols used.

Abstract — Social network analysis (SNA) has emerged as a powerful method for understanding the importance of relationships in networks. However, interactive exploration of networks is currently challenging because: (1) it is difficult to find patterns and comprehend the structure of networks with many nodes and links, and (2) current systems are often a medley of statistical methods and overwhelming visual output which leaves many analysts uncertain about how to explore in an orderly manner. This results in exploration that is largely opportunistic. Our contributions are techniques to help structural analysts understand social networks more effectively. We present SocialAction, a system that uses attribute ranking and coordinated views to help users systematically examine numerous SNA measures. Users can (1) flexibly iterate through visualizations of measures to gain an overview, filter nodes, and find outliers, (2) aggregate networks using link structure, find cohesive subgroups, and focus on communities of interest, and (3) untangle networks by viewing different link types separately, or find patterns across different link types using a matrix overview. For each operation, a stable node layout is maintained in the network visualization so users can make comparisons. SocialAction offers analysts a strategy beyond opportunism, as it provides systematic, yet flexible, techniques for exploring social networks. Index Terms—Social networks, interactive graph visualization, attribute ranking, coordinated views, exploratory data analysis. 1

In current windowing environments, individual windows are treated independently, making it difficult for users to coordinate information across multiple windows. While coordinated multi-window strategies are increasingly used in visualization and web user interfaces, designs are inflexible and haphazard. The space of such linkedwindow strategies is not well understood and largely unexplored. This paper presents a taxonomy of coordinations, identifies important components, and reviews example interfaces. This 2x3 taxonomy provides guidelines for designers of applications, user interface toolkits, and window managers. We hope to encourage construction of generalized, end-user programmable, robust, multiple-window coordination capabilities. KEYWORDS User Interface, Coordination, Taxonomy, Multiple Window Strategies, Information Visualization,Window Management INTRODUCTION Users are dealing with increasing quantity, variety, and interrelated-ness of information. User tasks are becoming...

To aid designers of digital library interfaces, we present a framework for the design of information representations in terms of previews and overviews. Previews and overviews are graphic or textual representations of information abstracted from primary information objects. Previews act as surrogates for one or a few objects and overviews represent collections of objects. A design framework is elaborated in terms of the following three dimensions: (1) What information objects are available to users, (2) How information objects are related and displayed, and (3) How users can manipulate information objects. When utilized properly, previews and overviews allow users to rapidly discriminate objects of interest from those not of interest, and to more fully understand the scope and nature of digital libraries. This paper presents a definition of previews and overviews in context, provides design guidelines, and describes four example applications.

To gain insight and understanding of complex information collections, users must be able to visualize and explore many facets of the information. This paper presents several novel visual methods from an information analyst's perspective. We present a sample scenario, using the various methods to gain a variety of insights from a large information collection. We conclude that no single paradigm or visual method is sufficient for many analytical tasks. Often a suite of integrated methods offers a better analytic environment in today's emerging culture of information overload and rapidly changing issues. We also conclude that the interactions among these visual paradigms are equally as important as, if not more important than, the paradigms themselves. Keywords: information visualization, user scenario, information analysis, document analysis 1 Introduction Information analysts face significant challenges dealing with the growing amount of information available and how to gain needed i...