Jonathan C. Roberts

State of the Art: Coordinated & Multiple Views in Exploratory Visualization

The area of coordinated and multiple views has been steadily developing and maturing over the past fifteen years. Some may say that it is a solved problem", while others argue that we are only just scratching the surface of the subject. Considering merely the CMV conference series, it is clear to see that in the early years researchers were concerned with models and techniques, while in latter years authors presented more work on how to apply these ideas to different domains. It is our view that there is still much research to be done, but the subject is changing and developing as a tool for visual analytics. This paper provides the state of the art" of CMV, it describes areas that should be developed further and looks at what the future may hold for coordinated and multiple views.

Visual comparison for information visualization

Data analysis often involves the comparison of complex objects. With the ever increasing amounts and complexity of data, the demand for systems to help with these comparisons is also growing. Increasingly, information visualization tools support such comparisons explicitly, beyond simply allowing a viewer to examine each object individually. In this paper, we argue that the design of information visualizations of complex objects can, and should, be studied in general, that is independently of what those objects are. As a first step in developing this general understanding of comparison, we propose a general taxonomy of visual designs for comparison that groups designs into three basic categories, which can be combined. To clarify the taxonomy and validate its completeness, we provide a survey of work in information visualization related to comparison. Although we find a great diversity of systems and approaches, we see that all designs are assembled from the building blocks of juxtaposition, superposition and explicit encodings. This initial exploration shows the power of our model, and suggests future challenges in developing a general understanding of comparative visualization and facilitating the development of more comparative visualization tools.

Exploratory visualization with multiple linked views.

Exploratory visualization enables the user to test scenarios and investigate possibilities. Through an exploration the user may change various parameter values of a visualization system that in turn alters the appearance of the visual result. For example, the changes made may update what information is being displayed, the quantity or resolution of the information, the type of the display (say) from scatter plot to line-graph. Furthermore, the user may generate additional windows that contain the visual result of the new parameters so they can compare different ideas side-by-side (these multiple views may persist such that the user can compare previous incarnations). Commonly these windows are linked together to allow further investigation and discovery, such as selecting by brushing or combined navigation. There are many challenges, such as linking multiple views with different data, initializing the different views, indicating to the user how the different views are linked. This chapter provides a review of current Multiple Linked-View tools, methodologies and models, discusses related challenges and ideas, and provides some rudiments for coordination within a geovisualization context. The types and uses of coordination for exploratory visualization are varied and diverse, these ideas are underused in geovisualization and exploratory visualization in general. Thus, further research needs to occur to develop specific geovisualization reference models and extensible systems that incorporate the rich variety of possible coordination exploration ideas.

Review of Designs for Haptic Data Visualization

There are many different uses for haptics, such as training medical practitioners, teleoperation, or navigation of virtual environments. This review focuses on haptic methods that display data. The hypothesis is that haptic devices can be used to present information, and consequently, the user gains quantitative, qualitative, or holistic knowledge about the presented data. Not only is this useful for users who are blind or partially sighted (who can feel line graphs, for instance), but also the haptic modality can be used alongside other modalities, to increase the amount of variables being presented, or to duplicate some variables to reinforce the presentation. Over the last 20 years, a significant amount of research has been done in haptic data presentation; e.g., researchers have developed force feedback line graphs, bar charts, and other forms of haptic representations. However, previous research is published in different conferences and journals, with different application emphases. This paper gathers and collates these various designs to provide a comprehensive review of designs for haptic data visualization. The designs are classified by their representation: Charts, Maps, Signs, Networks, Diagrams, Images, and Tables. This review provides a comprehensive reference for researchers and learners, and highlights areas for further research.

A coordination model for exploratory multiview visualization

We present a coordination model for exploratory multiview visualization. We base our work on current research in exploratory visualization and other disciplines. Our model is based on sharing abstract objects such as the visualization parameters of the dataflow model to achieve coordinated exploratory tasks in multiple views. This model describes how current coordinations in exploratory visualization work and allows novel coordinations to be constructed.

Pie chart sonification

Different acoustic variables such as pitch, volume, timbre and position can be used to represent quantitative, qualitative and categorical aspects of the information. Such sonifications are particularly useful for those with visual impairments; they are also beneficial in circumstances where visual representations would be impossible to use or to enrich a graphical realization. We demonstrate methods of representing an audible pie chart representation such that the hearer understands the information through an equivalent representation. We implement and evaluate five designs. In each, the user is positioned at the center of the chart and perceives the information through positional sound sources.

Visualization for the Physical Sciences

Close collaboration with other scientific fields is an important goal for the visualization community. Yet engaging in a scientific collaboration can be challenging. The physical sciences, namely astronomy, chemistry, earth sciences and physics, exhibit an extensive range of research directions, providing exciting challenges for visualization scientists and creating ample possibilities for collaboration. We present the first survey of its kind that provides a comprehensive view of existing work on visualization for the physical sciences. We introduce novel classification schemes based on application area, data dimensionality and main challenge addressed, and apply these classifications to each contribution from the literature. Our survey helps in understanding the status of current research and serves as a useful starting point for those interested in visualization for the physical sciences.

Angular Histograms: Frequency-Based Visualizations for Large, High Dimensional Data

Parallel coordinates is a popular and well-known multivariate data visualization technique. However, one of their inherent limitations has to do with the rendering of very large data sets. This often causes an overplotting problem and the goal of the visual information seeking mantra is hampered because of a cluttered overview and non-interactive update rates. In this paper, we propose two novel solutions, namely, angular histograms and attribute curves. These techniques are frequency-based approaches to large, high-dimensional data visualization. They are able to convey both the density of underlying polylines and their slopes. Angular histogram and attribute curves offer an intuitive way for the user to explore the clustering, linear correlations and outliers in large data sets without the over-plotting and clutter problems associated with traditional parallel coordinates. We demonstrate the results on a wide variety of data sets including real-world, high-dimensional biological data. Finally, we compare our methods with the other popular frequency-based algorithms.

Multiform glyph based web search result visualization

Searching for information on the web is hard; the user may not know what they are looking for, they may refine their search from information gathered by preliminary naive searches, and they may be looking for luminous sites that have many external links so that they can browse further. Information visualization can aid the user in many of these search related tasks. Certainly, the user is familiar with browsing and manipulating the search results through textual style interfaces, but they would gain a better understanding of the information through different presentation methods. Thus, we believe rank ordered lists should be used along-side abstract information visualization presentations. We present a system that displays multiple views of search result information. It provides views for displaying abstract visualization designs using multiform glyphs as well as a ranked text based list. Our engine also retrieves detailed information about the located sites (such as size of page, and quantities of internal and external links); and we describe two glyph designs that display this rich information.

Visual bracketing for Web search result visualization

We introduce a novel visual bracketing method that provides detail-in-context views where the inner part contains the Focus bracketed by the context information at a lower semantic level. We demonstrate two designs for Web search result visualization that obviate the need to frequently select the next button for viewing multiple search results.