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4. Legends and Tooltips
Legends and tooltips provide more information to viewers of your charts. Legends divide a bar or line by category, while tooltips provide more information when you mouse over part of a chart.
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Lesson Goal (00:12)
The goal of this lesson is to add legends and tooltips to our existing charts.
Understanding Legends (00:18)
A legend divides a chart into categories, with each category shown in a different color. The legend itself is located at the top of the chart, indicating which colors correspond to the different values of the legend field. We create a legend by dragging the relevant field into the legend well. For example, using the sub-region field as the legend for a bar chart divides each bar into a different segment for each sub-region.
A chart can only have one legend at any time. After creating a legend, we can customize it in the formatting pane. Here we can adjust the position of the legend, as well as its font size, font color and similar options.
Understanding Tooltips (01:36)
Tooltips are annotations that appear when we hover over a data point on a chart with the mouse. They display the numeric values of the data shown on the chart. They’re useful for combining numeric data with a visual chart, and they avoid the need to create tables to see numeric data.
All the fields used to create a chart are automatically added to the chart’s tooltip. These fields cannot be removed from the tooltip. You can add additional fields to the tooltip by dragging them to the Tooltip well. You cannot adjust how the fields are labeled in the tooltip. As a result, it’s important to make sure that the fields in your data are clearly named.
Using a tooltip can help deliver additional insights from an existing chart without making it more complicated.
Power BI offers two options that allow you to display more information within your visuals, legends and tooltips.
In this lesson, we'll add legends and tooltips to our existing visualizations.
As we've already seen, a legend can be used to break down a field by another field. In the 100% stacked bar chart, we've broken down revenue by sub region. We can see that each sub-region has a different color with the actual legend itself located at the top of the graph. Note that in this instance, the legend is too wide to fit on the visual. So we must click the arrow to scroll through the remaining entries.
As you can imagine, legends are most useful when analyzing a relatively small number of categories.
In Power BI, legends had their own well in the field section of the visualizations pane. To create a legend, we drag the relevant field to this well.
Only one field can be used to create a legend for each visual. Once we selected our legend, the formatting options become available in the formatting section of the visualizations pane. Let's select the formatting icon and select the legend.
Here, we have familiar options for altering size, color, and font of the legend text.
We also have the ability to move the legend around the visual.
We can move it to any side of the chart and we can ensure that it's centered as well.
We won't make any changes to the legend formatting at the moment. So we'll collapse the dropdown.
Tooltips provide more detail to data points on the visual.
Tooltips can be viewed in any kind of chart by hovering over a data point. As we hover the mouse over the revenue by region chart, the tooltip for a specific bar displays the name of the region and the total revenue for that region.
In the revenue by region and sub-region chart, the tooltip shows the region, sub-region and revenue for the sub region.
Tooltips are handy when you want to know the exact numerical value of a data point, without having to resort to tables. You may have also spotted a tooltips well in our visualizations pane. Note that this well does not currently have an associated field. Here, we still have a functioning tooltip. This is because Power BI automatically creates a tooltip for every visualization featuring all the fields we added to the visual.
You should be aware that you can not remove these fields or change how they're labeled in the tooltip.
As such, if you expect your readers to make use of tooltips, you should make sure that your field names are easy to understand. We can add more fields to the tooltip by dragging them to the tooltips well. Let's say we want our tooltip to tell us how many companies there are in each region. We can do this by selecting the visual, and then dragging company name to the tooltips well.
We then need to modify the tooltip by clicking the arrow next to first company name and selecting count.
Now when we hover over each bar, we can see the number of companies in that region. For example, the Northeast region has 334 companies while the South region has 343. Despite having more companies, the South region has slightly less revenue.
This tells us that the companies in the South have a lower average revenue than companies in the Northeast.
As you can see legends and tooltips provide another layer of insight, that's easily accessible to our audience. In the next lesson, we'll learn how to use a more advanced type of tooltip called report page tooltips.