Cornell University Ergonomics Web
DEA 3250/6510 CLASS NOTES
Control Panel Metrics
1. Basic recommendations -
a. Controls and displays should be arranged
in functional and/or sequential groups (spatially proximate)
b. Components should be grouped on the basis of function (controls
and displays are grouped by function).
c. Number of controls should be kept to a minimum (K.I.S.S.)
d. Control panels should minimize eye movement and hand travel yet
maintain adequate space for visual discrimination and control activation.
2. Visual field - Because the eyes are recessed some vision is blocked.
The nose also blocks some vision.
a. Visual Optimum (horopter) - visual optimum, extends 10-15°
below horizontal; that's why most prompters in mid-screen on computers.
This means we can see the floor more easily than the ceiling. Important
controls should be located where they can be seen well.
b. Zone of Sharp Vision - foveal <1°
c. Middle Field
- angle of view 1-40°, ex. area of screen - visual acuity is better a little below
horizontal than above
d. Outer Field - peripheral visual 41-70° more central, higher visual acuity
3. Overall design -
a. Overall Density of The Panel - is the ratio of free space
to the ratio of occupied space for entire panel, i.e. free space /occupied
space
b. Local Density - how closely placed the design entities are to
each other, determined by adjacency rules for each control or display. An
entity is a single control or a indicator.
c. Layout Complexity - position irregularity of functional areas
and the shape irregularity of each functional shape outline.
d. Display Grouping - number of functions at overall level and number
of controls and displays within each functional area.
e. Compatibility - refers to the degree to which C-D (control-display)
relationships are consistent with user expectations (population stereotypes).
Compatibility is especially important under stressful conditions when users
resort to their most 'natural' expectations. If these are not the correct
responses, errors or accidents may occur.
When control-display relationships are compatible:
(1) learning is faster
(2) reaction time is faster
(3) fewer errors are made (higher accuracy rates)
(4) user satisfaction is higher