Illustrating

Estimated Time: 10 minutes

Remember when your teacher assigned you a hefty chapter to read? You flipped through the assigned section of the textbook, desperately hoping for...yes, pictures! Viewing illustrations was so much more fun than reading text. In fact, when it comes to reading technical material, the vast majority of adults are still little kids—still yearning for pictures rather than text.

Figure 1. Good graphics engage readers in ways that text cannot.

Image credit: Nirmal Dulal CC BY-SA 4.0

According to research by Sung and Mayer (2012), providing any graphics—good or bad—makes readers like the document more; however, only instructive graphics help readers learn. This unit suggests a few ways to help you create figures truly worth a thousand words.

Write the caption first

It is often helpful to write the caption before creating the illustration. Then, create the illustration that best represents the caption. This process helps you to check that the illustration matches the goal.

Good captions have the following characteristics:

• They are brief. Typically, a caption is just a few words.
• They explain the takeaway. After viewing this graphic, what should the reader remember?
• They focus the reader's attention. Focus is particularly important when a photograph or diagram contains a lot of detail.

Note: By convention, the caption always follows the diagram.

Exercise

Target Audience: CS undergraduate students taking an "Introduction to Data Structures" class.

Consider the following three figures, each of which uses the same caption.

Caption A. A singly linked list node stores content and a reference to the next node.

Caption B. A singly linked list node stores content and a reference to the next node.

Caption C. A singly linked list node stores content and a reference to the next node.

Which of the three preceding figures best illustrates its caption?

Click the icon to see the answer.

• Figure A is bad. The chain is pretty, but information-free. The chain also erroneously implies that a single-linked list points both backwards and forwards.
• Figure B is okay. The illustration helps students realize that the first item points to the second item, the second points to the third, and so on. However, although the caption refers to both content and a pointer, the illustration shows pointers but does not show content.
• Figure C is the best and most instructive choice. The illustration clearly delineates the content part of each node from the pointer part.

Constrain the amount of information in a single drawing

Few intellectual tasks can be quite as rewarding as studying a fine painting, gradually uncovering layers of insight and meaning. People pay good money to do exactly that in the world's art museums.

Figure 2. You'd happily study this Van Gogh painting.

Image credit: Portrait of Pere Tanguy By Vincent van Gogh - Musée Rodin Public domain

By contrast, highly complex technical illustrations like the following tend to discourage most readers:

Figure 3. Complex block diagrams overwhelm readers.

Just as you avoid overly-long sentences, avoid overly-complex illustrations. Aim for simplicity and clarity in your diagrams to enhance understanding.

Focus the reader's attention

When creating illustrations, it's crucial to guide the reader's focus to the most important parts of the diagram.

Consider the following techniques:

• Use color strategically: Highlight key areas using color to draw attention.
• Add labels: Clearly label parts of the diagram to explain their function.
• Use arrows or lines: Indicate relationships or flow between elements.
• Simplify the design: Remove unnecessary details that may distract from the main message.

By applying these techniques, you can create illustrations that effectively communicate complex information.

Provide context

An illustration without context can be confusing. Always provide a brief explanation or context for your diagrams.

For example:

• Before the diagram: Introduce the concept or process that the diagram illustrates.
• After the diagram: Summarize the key takeaways or implications of the diagram.

This approach ensures that readers understand the relevance and meaning of the illustration.

Use illustrations to complement text

Illustrations should enhance the text, not replace it. Use diagrams to clarify complex concepts, but ensure that the accompanying text provides the necessary explanation.

Remember, a well-placed illustration can make a concept much clearer, but it should always be accompanied by descriptive text to provide full understanding.

Next unit: Sample Code