Issues in symbol design for electronic displays of navigation information

An increasing number of electronic displays, ranging from small hand-held displays for general aviation to installed displays for air transport, are showing navigation information, such as symbols representing navigational aids. The wide range of display technology and the different functions these displays support makes it difficult to design symbols that are easily recognizable across platforms. The goals of this effort are to identify features of navigation symbology that are problematic when presented on electronic displays and to develop a method to design and evaluate symbology that takes into account the different media (e.g., paper vs. electronic) and platforms on which they will be displayed. We address four questions to consider when evaluating the usability of a symbol: (1) Is the symbol easy to find? (2) Is the symbol distinctive from other symbols? (3) Is the on-screen symbol size appropriate? (4) Can all encoded attributes of the symbol be decoded quickly and accurately? Background findings and a proposed experiment to explore some of the higher-level issues related to the design of effective symbology are described.