Figures

People love figures; figures mean, "I don't have to read text." Let's face it--many people grazing books just look at the pictures and ignore the text.

Here are a few tips:

• The illustrations should enhance the text and the text should enhance the illustrations. The text preceding an illustration should help focus the reader's attention. That is, the text should tell the reader what to look for in the illustration. For example:

  
  In the following illustration, notice the small fan that 
  dissipates the excess heat.
  

• Keep illustrations physically close to the text that introduces them. Don't put the relevant illustration five pages later (except in a lab report where the illustrations, by custom, go at the end).

• Don't put too much information into a single illustration. Think of an illustration as being roughly equivalent to a paragraph. When the illustration becomes too dense, break it up into two or three separate illustrations.

• Focus on the important; omit the extraneous. [Illustration from Technical Editing by Judy Tarutz.]

• Caption illustrations. The only exception is when you are trying to tell a story completely without words. For example, the unpacking instructions of products sold worldwide often contain no words.

• Provide keys/legends if not obvious. Generally speaking, though, the encoding done within the figure should stand on its own without a key. Yes, some figures absolutely do require keys, but many do not and such keys force readers to work unnecessarily hard.

• In general, you should number your figures (for example, "Figure 8" or "Figure 2-3"). You must number all your figures when any of the following are true:
  • You are supplying a list of all the figures that appear in the book.
  • You cluster several figures in a batch.
  • Your text refers to figures that do not appear immediately afterward. For example, "Refer to Figure 8 back on page 17."

A Few Techniques Useful in Technical Communication

You are undoubtedly familiar with common figure types such as bar charts, pie charts, flow charts, and so on. In this section, we take a look at a few techniques beyond the ordinary.

Before and After

Side-by-side illustrations can be quite useful, giving the reader a chance to compare and contrast two similar figures. The following twin figures, from Content Server Product Overview (copyright FatWire Software), show two editions of an online newspaper--the one on the left is from the Sunday edition and the one on the right is from the Monday edition. The parallel figures demonstrate that although a newspaper's content changes daily, the layout remains constant.

• Example of Before and After

Process Flow or Data Flow

Flow charts are excellent, if somewhat bland, choices for displaying certain kinds of information (for example, code) to certain kinds of audiences (for example, EEs or programmers). Alternatively, you can use illustrations like the following to enliven process or data flow:

• Example 1 of data flow

• Example 2 of data flow

Hierarchies

Hierarchic products or concepts naturally lend themselves to illustrations. The following figure, from Content Server Product Overview (copyright FatWire Software), shows a hierarchy of products:

• Hierarchy example

The different layers of hierarchies often serve as useful chapters in a book. In such cases, you might consider re-using the hierarchy figure for each chapter, highlighting the relevant layer, for example:

• Hierarchy with focus example

Callouts

You often have to provide text to explain portions of a technical illustration. You can do this in one of two ways:

• By embedding the text inside the figure.
• By using callouts. A callout consists of two parts:
  • A line or arrow that points into the illustration.
  • Text, typically on the perimeter of the illustration.

Most professionals prefer callouts.

For example, consider the callouts in the following gorgeous illustrations (from Provence and the Cote D'Azur by Roger Williams). Notice how the callouts explain details without disturbing the beauty of the figure.

• Callout Example 1

• Callout Example 2

Insets

An inset is a blow-up of a subset of a figure. The inset focuses the reader on an essential part of the figure while allowing the reader to see the essential part in context with the remainder.

• Inset Example

[Preceding illustration from Technical Editing by Judy Tarutz.]