In creating an interactive visualization environment, interaction design should not be left to intuition or software defaults alone either; e.g., minimum number of operations (e.g., clicks) where possible to reach the goal is desirable, and a system that allows “overview, zoom, details-on-demand” is recommendable (Shneiderman, 1996).
Also consider using multiple linked views that can be switched on and off as needed (instead of displaying everything in one large and crowded visualization).
Multiple linked views allow exploring the data from various perspectives, and enable the viewer to see patterns that may have been hidden in one view (e.g., 2D-3D side-by-side views can give both useful but very different information, or being able to explore the data using various clustering methods or frequencies could balance between overview and detail). Brushing and linking (or otherwise highlighting) is very highly recommended in multiple-linked view systems. However, the number of displays here should be also closely considered for the viewers’ abilities, expertise and time. It is possible to show too much information at the same time, inadvertently creating. Multiple-linked views allow exploring the data from various perspectives, and enable the viewer to see patterns that may have been hidden in one view (e.g., 2D-3D side-by-side views can give both useful but very different information, or being able to explore the data using various clustering methods or frequencies could balance between overview and detail). Brushing and linking (or otherwise highlighting) is very highly recommended in multiple-linked view systems. However, the number of displays here should be also closely considered for the viewers’ abilities, expertise and time. It is possible to show too much information at the same time, inadvertently creating information overload (Eppler & Mengis, 2004).
When the task is explanation, the most typical scenario is where an expert (teacher, scientist, science journalist) tries to make something clear to others (students, an interdisciplinary audience or public). In explanation tasks, a safe assumption is that the viewer (whether experts or non-experts) is not going to look at the visualization for a long time, e.g., imagine a conference talk, a lecture or reading an online newspaper article. Because of this, the viewers possibly will find excessive information on display and/or interactivity expectations frustrating. A ‘reduced’ version in which the most important points are emphasized/highlighted with salient and appropriate visual variables (e.g., color hue and value, size, position, orientation.. (Bertin, 1983)), labeled without jargon and acronyms, and where possible, no more than 5-7 ‘bits of information’ are displayed at the same time (See Figure 1) should function best (Cowan, 2001; Miller, 1956).