Visuals and technical communication

Leading and misleading readers

Why use visuals?One good visual can replace a thousand

words of explanation in technical communication

As Edward Tufte says, “there are [data] displays that reveal the truth and displays that do not” (Visual 45).

What are the “right ways . . . to show data ”?

Each type of chart or graph is better suited to displaying one type of data

Select the display that most clearly illustrates your point

Select the right visual for the storyFind in your data an intriguing pointNever graph numbers just to include a

visualAlways make the visual accomplish

something

Types of visualsPie chartLine graphBar graphDot chartTable

MapPhotographLine drawingGantt chart

Pie chartShows how a part or

parts are related to the whole

Data needs to add up to 100% for pie chart to make sense

Figure 2.7 Collies, shepherds, and retrievers accounted for more than 70% of dogs placed at the shelter last year.

Line graphLine graph

compares items over time, to show frequency or distribution or to show correlations

Figure 2.8 Buster’s weight gain from six weeks to six months. He was born Jan 9. Source: King St. Veterinary Clinic medical records.

Bar chartBar chart compares

items, compares items over time, shows frequency, distribution, or correlation.

Figure 2.9 Buster’s weight gain from six weeks to six months.Buster was born Jan. 9. Source King St. Veterinary Clinic medical records.

Dot chartDot charts show correlationShow clusters of data so viewers can see

relationships

TablesTables display exact figures (when

accuracy and detail are important)

Table 2.11 Experimentally Determined Optimal pH of Micro-organisms

Organism Optimal pH

S. cerevisiae 5.1-6.9

E. coli 8.1 or higher

L. plantarum 3.0 or lower

S. aureus 8.1 or higher

MapsMaps show location or compare two items

Figure 2.12. A map shows the location of British Columbia in relation to the larger context of North America.

PhotographsTo reproduce exact

detail or show something being used

To show size. With extra large or extra small objects, include a reference point to illustrate the size.

Figure 2.13. The trees behind this totem pole illustrate the scale of the carving in downtown Victoria, BC.

Line drawings

Figure 2.14 The digital photograph does not help users locate the birdbath contained within this waterfall design.

Figure 2.15 The darkened areas of the sketch clarify for viewers the path of the water in the falls, as well as highlighting the location of the falls' birdbath.

Line drawings (cont’d)Line drawings emphasize specific details or

show dimensionThey omit details that are irrelevant to your

point

Gantt chartsGantt charts indicate timelinesUsed on proposals or progress reports to track

stages of project

Conventions for using visualsA titleAll units labelledSource of the dataSource of visual (if you didn’t create

yourself)

Misleading visualsConventions are sometimes subverted to

obscure disadvantageous information

Many more women than men are employed in teaching

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employment by gender in selected industries

Num

bers

em

plo

yed (

in t

housands)

Men

Women

Figure 2.17 Starting the x-axis at 100 in this graph exaggerates the number of women vs. men employed in these industries. This graph makes it appear that no women work in natural resources, which is not the case. Source: Statistics Canada, May 2006.

Adding visual interest can obscure the informationChart junk

2003 2005 2006 2008

Figure 2.18 Sales figures for Sweetest Day are increasing steadily and expected to continue to do so over the new two years.

Use uniform-sized iconsUse icons of a uniform size so units can be

compared accurately

in thousands

2003 2005 2006 2008 (projected)

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