Charts play a crucial role in conveying insights, which is why elements like chart legends are essential tools for interpreting colour variations and understanding complex data sets. Let’s dive into the nuances of chart legends with five tips designed to make your charts more impactful and easier to understand.
Chart legends label and help explain colour variations in your charts. When used effectively, they improve readability and prevent misunderstanding. Chart legends work best when there is more than one metric or dimension, and where colour variations need an explanation in a chart.
Let’s work through a few real-world examples and tips to see how chart legends can enhance or detract from a data visualisation.
In this first example, variation occurs when there is more than one metric and the chart legend explains their meaning. In the chart below, dark blue indicates Start of Period (SOP) Headcount, while light blue represents End of Period (EOP) Headcount. It is easy to see at a glance which number and bar corresponds to each metric.
In another example, variation can be depicted when there are one or more Dimensions with more than one group selected. As shown below, the colour variation indicates Male and Female Gender – dark blue for Male and light blue for Female. Again, meaning is quickly and easily discerned with the chart legend.
What happens to chart legends when there is no colour variation? Single-colour charts such as the example below with a single metric like (EOP) Headcount over time don’t usually need a chart legend because all of the bars will be the same colour. In these situations, a chart legend is unnecessary as it only serves to repeat information.
For cases where only a single metric is included, we recommend the Option to Hide Metric name as this information will likely be already mentioned elsewhere, likely in the chart title or the Storyboard page. In Tile Settings, slide the toggle for Hide Metric Name to On. For pie charts, the Hide Metric option will apply when Legend is set to None and Series named selected as Data Label.
Chart legends also include the selections for the Dimensions. A selection controls what is visible on the chart, whereas a filter controls what the dataset includes. When only a single selection is made, they work similarly. However, selections show in the chart legend, while filters display on top of the chart and can be hidden if desired. Therefore, it’s best practice to choose a filter to limit chart clutter in cases where selection is used to select a single point of the data.
In the case that multiple metrics are included on a chart or the metric name is not mentioned anywhere else, Group legends should be turned on to avoid any ambiguity.
Mastering the use of chart legends is essential for creating clear and effective data visualizations. By following these tips, you can ensure your charts are not only visually appealing but also easy to understand. Whether you're dealing with multiple metrics, color variations, or trying to minimize clutter, thoughtful use of chart legends can significantly enhance the impact of your data.
Visit One Model's Help Center to learn more about custom chart legends.