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 |