3. Text, Labels, and Legends

Consider the following guidelines when adding axes, titles, legends, values, and series labels to your charts:

Titles

Add a descriptive title to guide the reader in interpreting your chart. It is good practice to title the chart using an action title. An action title presents the essential takeaway for the chart. This makes it easier for the audience to understand the insight presented in the chart³.

Data labels

When there are few data points, place the data labels directly on the encodings (bars, points, slices). If direct labeling will impede readability, use a legend.

Consider labeling the endpoints when presenting a time series.

Axes labels

Write labels for the x and y axes horizontally. Note: When labeling data points directly, it is unnecessary to provide a y-axis.

Figure 3.1 highlights the chart with added labels to help interpret the message.