GEOGRAPHIC VISUALIZATION

ing away from reality -The interplay between realism and abstraction needs to be further explored. Augmented reality, for example, couples these two to create new perspectives of previously unseen displays. The challenge is to automatically create a sketch to convey a desired action more effectively than can a real picture. Much research has been directed toward realism, and indeed, more is required. “At the same time, realism is in some sense easier, as we can draw on the quantitative tools of physics and mathematics. When we want to create an abstraction that somehow conveys key ideas while suppressing irrelevant detail, we need to draw on the lessquantified tools of perceptual psychology and cognitive psychology, and the vast knowledge of cartographers and animators” (Foley 2000). This is likely to vary with the application. We need to be able to determine what the right amount of realism for visualization to be maximally effective. For example, imagine an “abstraction” control, interactively varying the realism of the scene. Displaying more data -There has already been some work by the visual data mining community to further the developments that allow massive datasets to be combined on a computer screen using averaging, aliasing, and other methods (Keim and Kriegel 1996, Keim 1996). As the volume of spatial data available continues to grow, the need for methods for displaying much of it, perhaps simultaneously, will increase. Displaying more pixels -We need to look for ways to use solutions that will provide desk-sized and wall-sized work areas with sufficient pixels to maintain the image quality we have become accustomed to on our desktop monitors. Although faster graphics engines are being developed, we continue to display information on less than two square feet of display area with one to three million pixels that subtend perhaps 25 degrees at normal viewing distance. Or we use a projection system and magnify each pixel onto a large screen that, when viewed from a distance, is the same 25-degree field of view. The human eye, however, has a field of view of more than a 180degrees. Displaying fewer pixels -At the same time that we advocate higher-resolution and larger display surfaces, we are increasingly working with smaller, lower-resolution displays found in personal digital assistants (PDAs), cell phones, car navigation systems, and other information appliances. “Consider PDAs and intelligent communicators on the palm-top, information appliances on the counter-top, automotive navigation systems on the dash-top, and messaging watches on the wrist-top. Making the best use of a limited number of pixels is in many ways more challenging than working with millions of pixels” (Foley 2000). User interfaces for 3-D creativity -Rather than doing creative work with traditional tools and then transferring the results into a computer graphics system for further work, we need to develop tools that allow the same subtle freedom as traditional tools in terms of greater expressiveness, more rapid development of prototypes, and sensory feedback. The challenge is to build interfaces and devices that allow the creative process of compiling a display to be developed with the computer as well. Long-term Visualization Research Challenges Imaginative information visualization -There is endless opportunity for creativity in discovering new ways to present information. Advancements in this area will lie at the interface of computer graphics and graphic design. “Computer graphics empowers so many techniques concerning time variation and 3-D and interactive navigation that knowledge of and enhancement of these computer graphics techniques is an inherent, essential part of the creative challenge, awaiting integration with graphic designers' awareness of aesthetics and perceptual issues” (Foley 2000). Automated creation of information and information visualizations -The underlying challenge is to automatically create informative and aesthetic visualizations that help the user understand the underlying data being presented. This requires that the user express what information is being sought and that an automated assistant then synthesize a visualization that conveys that information. The challenge is to have a system where the user state the problem, "Please show me the relationships between landscape conditions and in-stream habitats . " and suddenly have an aesthetically pleasing and effective graphic created based on domain knowledge and graphic design knowledge. Work in this area has already been advanced to some level by Senay and Ignatius (1998) and Gahegan and O’Brien (1997).