How to rename the Metric legend on a Line Chart or Bar Chart
By default, the Metric name in the legend below a Chart is set to reflect the name of the Metric displayed on the Chart. It is possible to rename or change the text for a specific visualization from the Advanced Settings window.
The ability to customize the legend is useful if you are using different terminology in your company or if you want to further clarify what's displayed on the Chart.
Pro Tip: If the legend is ever customized for a Datablock, it will no longer update if a new Metric is added to the Datablock. If you want the legend to automatically update, it's recommended that you delete the Datablock and rebuild it on the Databoard.