5.6.1
General Display Requirements
5.6.1.1
Lack of Ambiguity
Display indicators should clearly and unambiguously direct and
guide the appropriate control response.
5.6.1.2
Use of Digital Displays
Digital displays should be used for the presentation of quantitative
data when exact values are required and continuous trend or rate of
change information is not required.
5.6.1.3
Digital Readout
A digital readout should not be used when the information changes
with a frequency of more than 0,5 Hz; a higher frequency may be used
when the information perception from other displays is not disturbed.
5.6.1.4
Update of Information
The displayed information should be continuously updated.
5.6.1.5
Information Duration
For signals or displays which frequently or consistently change
their outputs, the information displayed should have durations of
sufficient length to be reliably detected under expected operator
workload and operational environment.
5.6.1.6
Display Simplicity
Displays should present the simplest information consistent
with their function; information irrelevant to the task should not
be displayed, and extraneous text and graphics should not be present.
5.6.1.7
Only Necessary Data
Displayed
Displayed data should be tailored to user's needs, providing
only necessary and immediately usable data for any transaction. Displays
should not be overloaded with extraneous data.
5.6.1.8
Uncluttered Displays
Displays should be as uncluttered as possible.
5.6.1.9
Display of Important
Information
Highly important and/or frequently used information should be
permanently displayed.
5.6.1.10
Display Fields for
the Display of Important Information
The display fields for the presentation of the most important
and/or frequently used information should be assigned exclusively
to them and should not be used to display any other information.
5.6.1.11
Graphic Display Enhancement
With Numeric Values
When precise reading of a graphic display is required, the display
should be annotated with actual data values to supplement their graphic
representation.
5.6.1.12
Indication of Scale
The scale of maps and charts (data) shown on the display should
always be indicated.
5.6.1.13
Aiding Distance Judgements
When a user must judge distances accurately on a map or other
graphic display, computer aids should be provided for that judgement.
5.6.2
Arrangement of Visual
Information
5.6.2.1
Screen Organization
A standard display screen organization should be evident for
the location of various system functions (such as a data display zone,
control zone, message zone) from one display to another.
5.6.2.2
Grouping of Information
on a Display
Information on a display should be grouped according to obvious
principles, e.g., by task, system, function, sequence, etc., based
upon the user's requirements in performance of the ongoing task.
5.6.2.3
Demarcation of Groups
Information groups should be visually distinct, e.g., separated
by blanks, lines, colour coding, or other means.
5.6.2.4
Consistent Presentation
The arrangement and presentation of identical visual information
should be consistent from application to application.
5.6.3
Visual Display Units
(VDU)
5.6.3.1
Night Display
All information should be presented emitting as little light
as possible at night.
5.6.3.2
Day and Night Legibility
Displays should be capable of being read day and night.
5.6.3.3
Background Colour
A single neutral background colour should be used that has a
hue which allows the information (foreground) to be easily visible
and which does not distort or interfere with the coding aspects of
the display.
5.6.3.4
VDU Resolution
The display should have adequate resolution; i.e., users can
discriminate all display elements and codes from the maximum intended
viewing distance.
5.6.3.5
VDU Contrast
The contrast ratio of the display should be greater than 3 :
1 and less than 15 : 1; a contrast ratio of 7 : 1 is preferred.
5.6.3.6
Background Luminance
A background luminance level of 15 cd/m2 to 20 cd/m2 should be used at daylight.
5.6.3.7
Display Luminance
The display luminance should be between 80 cd/m2 to
160 cd/m2 at daylight.
5.6.3.8
Flicker
The display should be "flicker free"; the refresh rate should
have a minimum of 65 Hz.
5.6.3.9
Image Continuity
The display should maintain the illusion of a continuous image,
i.e., users should not be able to resolve scan lines or matrix spots.
5.6.3.10
CRT Image Linearity
The display should be free of geometric distortion.
5.6.4
Coding and Highlighting
5.6.4.1
Highlighting Selected
Data
When a user is performing an operation on some selected display
item, that item should be highlighted.
5.6.4.2
Flash Coding
Red flash coding should be reserved for Alarms.
5.6.4.3
Redundant Colour Coding
Colour coding should be redundant with some other display feature,
i.e. add colour coding after displays have already been designed as
effectively as possible in a monochrome format.
5.6.4.4
Easily Discriminable
Colours
When selecting colours for coding discrete categories of data,
those colours should be easily discriminable.
5.6.4.5
Minimum Colour Differences
When colour coding is used for discriminability or conspicuity
of displayed information, all colours in the set should differ from
one another by a minimum of 40 ΔE (CIE L*u*v*) distances.
5.6.4.6
Establishing Standards
for Shape Coding
When shape coding is used, codes should be based on established
standards or conventional meanings.
5.6.5.1
Font Style
A clearly legible font should be utilized. Fonts should have
true ascenders and descenders, uniform stroke width, and uniform aspect
ratio. .
5.6.5.2
Meaningful Abbreviations
When abbreviations or acronyms are used, they should be meaningful,
in common usage and kept to a minimum.
5.6.5.3
Units of Measurement
The units of measurement (volts, psi, inches, etc.) should be
labelled.
5.6.5.4
Appropriate Use of
Icons
Icons should be designed to look like the objects, processes,
or operations they represent, by use of literal, functional, or operational
representations.
5.6.5.5
Representation and
Discrimination
Each icon or symbol should represent only one object or function,
and should be easily discriminable from all other icons and symbols.
5.6.5.6
Size
Icons and symbols should be large enough for the user to perceive
the representation and discriminate it from other icons and symbols.
5.6.5.7
Highlighting
An icon or symbol that the user has selected should be highlighted.
5.6.5.8
Scaling in Standard
Intervals
Scales should have tick marks at a standard interval of 1, 2,
5, or 10 (or multiples of 10) for labelled divisions; intervening
tick marks to aid visual interpolation should be consistent with the
labelled scale interval.
5.6.5.9
Expansion of Graphic
Displays
When a graphic display has been expanded from its normal coverage,
some scale indicator of the expansion factor should be provided.
5.6.5.10
Unobtrusive Grids
When grid lines are displayed, they should be unobtrusive and
not obscure data elements (e.g., curves, plotted points).