Iconification and Omission in Information Exploration

Introduction Because users find it difficult and unpleasant to explore cluttered displays, a number of visualization systems reduce clutter by allowing users to view detail selectively. Early work includes fisheye views and the Spatial Data Management System (SDMS) [2,3]. More recent paradigms include the Pad zoomable interface and Magic Lenses [4,1]. By its very nature, this strategy for clutter reduction eliminates certain details from the display. Two processes are common. First, a graphical representation may be iconified. Iconification is the process of transforming a graphical representation into a more compressed graphical representation. This compression may take a number of forms. For example, the graphical representation may change shape or detail may be omitted. Note that information may be lost during iconification. Consider a circle that represents a city. Suppose the radius of the circle is proportional to the population of the city. If the circle is iconified to a fixed-size dot, the data about the city’s population is lost. Second, data elements may be omitted, i.e., eliminated from the current view. In this case, all information about the omitted object is lost. In general, the user can navigate to the information that has been removed, e.g., in semantic zoom systems an icon may change into a more detailed graphical representation when the user zooms in on it. However, in many cases, the user may not be aware that a graphical representation has been iconified or omitted. This situation is particularly likely in information exploration tasks in which the user has only a vaguely defined goal. In these cases, the user may never discover certain information relevant to their task. We discuss the potential downfalls of iconification and omission in the next section of this paper. We then propose three techniques that (1) help the user become aware of the existence of detail of interest and/or (2) help the user navigate to this detail.