Legends are essential components of visualization as they help your audience understand and interpret the data displayed.
Here are some guidelines for orienting a legend effectively:
Positioning: The first thing to consider is where to place your legend. Ideally, the legend should be close to the data it’s describing. For example, if we’re looking at a bar chart, you could put the legend either above or below the bars or even alongside the chart. For a map, you could place it near the geographical data, such as in a corner or along the side. Ensure the legend doesn’t obstruct any data points, and keep it within the viewer’s immediate line of sight!
Horizontal vs. vertical orientation: Horizontal legends work best when there’s plenty of space along the width of the chart, such as at the top or bottom. This way, the labels can be easily read in one continuous line. When overall space is limited, a horizontal legend utilizes the chart’s width more effectively than a vertical legend. Vertical legends, on the other hand, work well when positioned along the side, when there are too many categories to fit horizontally, or when the category labels are lengthy. Choose the orientation that best fits your visualization’s available space and overall layout.
Consistency: If you have multiple visualizations in your presentation or report, try to keep the legend orientation consistent across all of them. This will make it easier for your audience to understand and absorb the information, as they won’t need to readjust their focus between visualizations.
Clarity: Ensure that the labels in your legend are concise and easy to read. Keep the text size large enough to be legible but not so large that it overwhelms your data. Also, use clear, descriptive labels that accurately represent the data being visualized.
Color and design: To avoid confusion, use colors, symbols, or patterns in your legend that match the corresponding data points. Suppose you are using colors; select ones that contrast nicely with the background and with each other. The legend’s design should complement your visualization’s overall design without drawing attention away from the data itself.