Generate and Test

Generate and test is a strategy for designing automatic visualization systems. The goal for such a system would be to eliminate the need for users and programmers to specify, design and arrange a display each time output is needed from a program. Instead, users would focus their attention more appropriately on the tasks of determining and describing the informational content to be presented in a display.

The generate and test strategy requires a set of graphic primitives, rules for generating visualizations form the primitives, and criteria against which to test each generated visualization. For instance, in the natural language domain, words form the primitives of the English language, grammar rules tell us how to generate sentences from words, and our knowledge of the real world is the criterion by which we test a sentence to determine if it makes sense. In the graphical domain, Mackinlay (APT) was the first to use the generate and test paradigm. He worked with 2D discrete data presented in business-graphics formats. His graphic primitives include circles, bars, lines, marks (e.g. + and o) with visual attributes (such as color, size and orientation). The primitives are organized into primitive graphical languages, and a grammar is used for generating alternative representations.

Rules for testing the generated alternatives are derived from a combination of experimental studies and experience-based guidelines. The rules concern what types of information (nominal, ordinal, quantitative) can be expressed by different primitives, and the relative effectiveness of alternative primitives which could be used for the same type of information. For instance, size and saturation can both be used to express quantitative data, but size is more effective than is saturation.

Systems which are based on the generate and test paradigm are:


References:

Roth, S. and Mattis, J. (1990) Data Characterization for Intelligent Graphics Presentations. In Proceedings CHI '90 April. pp. 193-200

Foley, J. and Ribarsky, W. (1994) Next-Generation Data Visualization Tools. In Scientific Visualization (Academic Press Ltd. 1994) pp. 103-127 Scientific Visualization (Academic Press Ltd. 1994) pp. 103-127


Visualization Concepts