Comparison of coding methods (Maguire, 1987)

 

Coding method

Maximum number of codes Comments
Alphanumerics Unlimited Highly versatile. Meaning can be self-evident. Location time may be longer than for graphic code.
Shapes 10-20 Very effective if code matches object or operation represented
Color 4-11 Attractive and efficient. Excessive use confusing. Limited value for the color-blind.
Line angle 8-11 Good in special cases, for example, wind direction.
Line length 3-4 Good. Can clutter display if many codes displayed.
Line width 2-3 Good
Line style 5-9 Good
Object size 3-5 Fair. Can take up considerable space. Location time longer than for shape and color
Brightness 2-4 Can be fatiguing, especially if screen contrast is poor
Blink 2-4 Good for getting attention but should be suppressible afterwards. Annoying if overused. Limit to small fields.
Reverse video No data Effective for making data stand out. If large area is in reverse video, flicker is more easily perceived.
Underlining No data Useful but can reduce text legibility.
Combination of codes Unlimited Can reinforce coding but complex combinations can be confusing