The basic idea with focus–plus–context–visualizations is to enable viewers to see the object of primary interest presented in full detail while at the same time getting a overview–impression of all the surrounding information — or context — available.
Focus+Context start from three premises: First, the user needs both overview (context) and detail information (focus) simultaneously. Second, information needed in the overview may be different from that needed in detail. Third, these two types of information can be combined within a single (dynamic) display, much as in human vision.
[Card et al, 1999]
Focus–plus–context–systems therefore allow to have the information of interest in the foreground and all the remaining information in the background simultaneously visible — Seeing the trees without missing the forest.
A principle of Information Visualization
– display the most important data at the focal point at full size and detail, and display the area around the focal point (the context) to help make sense of how the important information relates to the entire data structure. Regions far from the focal point may be displayed smaller (as in Fisheye Views) or selectively.
[Usability First, 2003]
- Show selected regions in greater detail (focus)
- Preserve global view at reduced detail (context)
- No occlusion (all information is visible simultaneously)
The main problem of information visualisation
is the insufficient space, which restricts the user in showing detail and context contemporaneous, is called “presentation problem”. The Focus+context system allows the user to show detailed informations linked with the context, by also having the possibility to focus on other informations by interacting with the system.
 Related Terms
- [Card et al, 1999] Card, S.K., Mackinlay, J.D., and Shneiderman, B. (Eds.) Readings in Information Visualization: Using Vision to Think, pp. 1-34, Morgan Kaufmann Publishers, San Francisco, Califomia, 1999.
- [Dürsteler, 2002] Juan C. Dürsteler: Focus+Context, Inf@Vis!, 22. Created at: April 2002. Retrieved at: November 2004. http://www.infovis.net/printMag.php?num=85&lang=2
- [Keahey, 2003] T. Alan Keahey. Network Visualization Course. Indiana University. 2003, ftp://ftp.cs.indiana.edu/pub/tkeahey/FocusContext.ppt
- [Leung and Apperley, 1994] Y. K. Leung and M. D. Apperley. A review and taxonomy of distortion-oriented presentation techniques. ACM Transactions Computer-Human Interaction, 1(2):126-160, June 1994.
- [Usability First, 2003] Usability First, Usability Glossary. Retrieved at: 2003. http://www.usabilityfirst.com/glossary/focuscontext/