sm2222: information design and visualization public information symbols 4 november 2005

SM2222: Information Design and Visualization

Public Information Symbols

4 November 2005

A symbol is essentially a picture or visual representation which depicts one or

some of the features of referent (real-world object or concept) it represents.

Advantages of using symbols

• They can be identified at a greater distance and more rapidly

• They can be identified more accurately when seen at a glance

• They can be can seen better under adverse viewing conditions

• They can be understood by people who do not read the language of the country

Advantages of using symbols

• They can be detected more readily than can word signs

• They can be represented information in a spatially condensed form

• They can be multi-dimensional, incorporating such features as color, shape and size, as well as combination of these, into the basic symbol message

Categories of symbols

• Industrial and occupational (in the workplace)

• Representing methods (machines, instructions)

• Management of public places (transportation, museums, hospitals)

• Knowledge

• Particular activities (sports)

Criteria for effective symbols

• It must command attention or be easily detected by the person who needs the information

• It must be legible at the appropriate distance and must often be legible when seen for a very brief time (e.g. a highway sign) or under adverse viewing conditions (e.g. low illumination, glare)

• It must also be quickly identified, as drivers often have only a second to interpret and respond to the message

• It must be clearly understood and the action to be taken in response to the message should be immediately obvious

Criteria for effective symbols

• Comprehension

• Conspicuity

• Reaction Time

• Legibility Distance

• Learnability

• Potential users

A model of the relation between signal, sign and referent

SignalPicture/ Abstract Drawing

Sign RelationIconic or Symbolic

ReferentWorld Object/ Abstract Concept

Classifications of symbols

• Form - includes resemblance, or use of an analogous image (e.g. the ‘falling rocks’ road sign symbol)

• Exemplar - use of a typical example for a class of objects (e.g. a book to represent ‘library’)

• Symbolic - an image represents a higher level of abstraction than the image itself (e.g. cracked wine glass to show ‘fragility’)

• Arbitrary – use of an image that has no relationship to the referent (e.g. the symbol for ‘biohazard’)

Understanding symbols

• The psychological processes involved in recognizing and understanding pictographs

• Abstract ones invoke referents at conceptual level (e.g. computer command), whereas concrete ones invoke specific objects or exemplars

• Cultural experience and context play a role in the understanding of symbols (e.g. railway train sign)

• A warning message indicate either the nature of the hazard or its consequences

• It will also be determined its ease of design and effectiveness

• Early development of icons for computer (e.g. papers, folders, mail boxes), but many operations now just do not have pictorial representations

Choice of symbols

Should drivers be told what they can (or must) do, OR what they cannot do on the road?

Problems with symbols

• Many are too small to be seen from a distance, even at reading distance (e.g. on maps and brochures)

• They have very small or unnecessary detail

• Some are very similar to others, leading not only to confusion between symbol images, but also to misunderstanding of the messages

• The meaning of graphic symbols are not always obvious to the user

• It cannot communicate with people who do not read the language of the country

• Many symbols differ not only by style, but among cultures and over time within a culture (e.g. knife and fork vs. chopsticks depict restaurant)

Methods for evaluating symbols

• Field and laboratory evaluation of symbols

Methods for evaluating symbols

• Psychological methods - reaction time, glance legibility, legibility distance, comprehension, preference ratings and signal detection.

Methods for evaluating symbols

• Comprehension Test (the standard ISO procedure – write out the symbol’s meaning)

ISO procedure for the development of public information symbols

Methods for evaluating symbols

• Semantic Differential Method – a series of selected bipolar adjectives (e.g. beautiful – ugly, strong – weak), then write out the symbol’s meaning

Ugly Beautiful

Weak Strong

Complex Simple

Meaning:

Meaning:

Meaning:

Telephone

Telephone

Telephone

ISO 1979

Methods for evaluating symbols

• Comprehension Estimation Procedure – The correlations score of symbols between estimated and actual comprehension level

Methods for evaluating symbols

• The effects of context and familiarity on comprehension

With full context – 2 sentence descriptione.g. You are walking in an international airport. This symbol is located on a sign extending from the wall overhead

With partial context – 2 word descriptione.g. international airport

No context information

Guidelines for the image content of symbols

• Standardize the image content description in the early stage

• But it permit slight variation in the graphical image for cultural differences, corporate identity requirement, changes in technology and creativity from the designer

• Fundamental design criteria of symbols for ‘comprehension’ and ‘legibility’ must still be met

• Symbols must be meaningful, legible, learnable, memorable and used consistently

• Emphasize the distinguishing features which are more easily recognized even than photographs

• It may involve ‘stylization’ or the portrayal and exaggeration of the useful and essential elements of an object relevant to its identification

Guidelines for the graphic design of symbols

• Uniformity of design – both within and between symbol system aids understanding

Guidelines for the graphic design of symbols

• Complexity and detail – symbols should be as visually simple as possible and involve an easily discriminated figure with few details

Guidelines for the graphic design of symbols

• 2 types of details in symbols – those necessary for adequate visibility at a greater distance and those desirable for understanding of the message

Guidelines for the graphic design of symbols

• Specific symbol elements – it is most appropriate to use side views of certain components

Guidelines for the graphic design of symbols

• Legibility

– feature size

– feature separation / gap size

– feature familiarity

– contrast

A Design Case Study

Visual alerts to machinery hazards

The demands a visual message with characteristics:

- It should be in the immediate vicinity of the hazard- It should be contrast with the background- It should instantaneously identify the nature of the hazard- It should indicate the consequences which can result if precaution are not taken- It should indicate the level of intensity or seriousness of the hazard- It should indicate instructions on how to avoid the hazard