Design Pattern: IM(9) Distortion


The operator would like to work at multiple levels of detail of alarm information (IF(2) Display resolution management). He would need to see such levels simultaneously


The human operator needs to move rapidly and fluidly between levels of detail of alarm information.


Support focused and contextual views based on distortion, which integrates focus and context views into a single display where all parts are concurrently visible: the focus is displayed seamlessly within its surrounding context. Distortion presents the focus area at a higher magnification than the rest of the display [140]. The result is a distorted view of the large display page because different parts of it give the user contextual information. Key features of the unmagnified global structure inform the user of the existence and location of other parts of the information structure and support the interpretation of local details.

Known uses
Fig1. Geographical map with a magnifying glass effect around a specific area
Fig2.Geographical map of power generation with a magnifying effect around a specific area

Distortion-oriented techniques prioritize the use of display space based on importance, while providing context to the rest of the display. They decrease the short term memory load associated with assimilating distinct views of a system, and thus potentially improve user ability to comprehend and manipulate the information. (Human-system interface design review guidelines. Division of Systems Analysis and Regulatory Effectiveness, Office of Nuclear Regulatory Research, US Nuclear Regulatory Commission, 2002.)