ABSTRACT
Human understanding of any object, concept, or process usually requires the observation and measurement of multiple variables. The economic status of a nation, for example, is typically described by a number of financial indices. Likewise, the operational status of a process, such as the conversion of solar energy into electricity, depends on system inputs and component efficiencies. The present article discusses the progress made, and problems encountered, in using multiple attributes of a visual display as analogs for the multiple measures used to describe such physical and conceptual entities. The article also describes some of the principles used in the design of such displays.
