Designing Charts: Chart Legends

Chart legends play a crucial role in helping our audience understand and interpret the data in our visuals effectively. Here are some key elements of a good chart legend.

  1. Position: Choose a suitable position for your legend, usually at the top or bottom of your chart. It’s important to ensure the legend is easily visible and does not interfere with the data.
  1. Color and style consistency: Maintain consistency in the color and style of your chart elements and the corresponding legend items. This helps in making a clear connection between the data and its attributes.
  1. Label clarity: Use clear, concise labels in your legend. Avoid using jargon or abbreviations that your audience may not easily understand.
  1. Ordering: Arrange your legend items in a logical order that mirrors the arrangement of your data or chart elements. Such ordering may consider the natural progression of data, importance or magnitude, sequential or categorical order, or alignment with chart data. This will help your audience quickly connect the legend and the data.
  1. Font size and readability: Ensure that your legend text is easily readable using a font size and style consistent with the rest of your visual.
  • Example: If your chart labels are in a 12-point font, use the same size for your legend text. Avoid using overly decorative fonts that may be difficult to read.
  1. Minimalism: Keep your legend as simple and clean as possible. A clutter-free legend enables the viewer to focus on the data without any distractions.
  • Example: In line charts, sometimes all it takes to make a legend clear is to add a label directly to the line rather than having a separate legend box with multiple items.