ArcTrees: Focus+Context Visualization of Relations in Hierarchical Data
ArcTrees help to visualize hierarchical and non-hierarchical relations within one interactive visualization. Such a visualization is challenging because it must display hierarchical information in a way that the user can keep his or her mental map of the data set and include relational information without causing misinterpretation. Our tree view is derived from traditional Treemaps and augmented with an arc diagram to depict relations. In addition, we present interaction methods that allow the exploration of the data set using Focus+Context techniques for navigation. The development was motivated by a need for understanding relations in structured documents but it is also useful in many other application domains such as project management and calendars.
In this example you see the hierarchical structure of a book with its chapters, sections, and with tables, images, and text paragraphes as leaf nodes. Arcs are drawn between text paragraphs that cite other parts of the book. Some of the nodes in this example are collapsed (they are shown a bit brighter and are much more visible in the program on the screen than in this picture) and lighter arcs indicated that the relation connects to a hidden node. The circle under certain nodes show that there are hidden relations in the collapsed node that will be show when the node is expanded (this is done similarly in Windows Explorer where you click on a folder to "expand" its contents).
This is how I envision this visualization could be used in a text editor or viewer to show the text and text relations while reading. Note: this is only a mockup.
This example shows arcs for recurring events in a calendar. Note how you can easily spot the one week where a usually recurring event does not take place.
A video for my one-minute-madness at InfoVis 2005
|Download the video|
Petra Neumann, A comparison of 2D nested visualizations of hierarchies, 681 Class Project Paper, (PDF).