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7. Combo Charts
Combo charts allow you to combine a bar chart and a line chart on the same visual, even if their numeric scales vary considerably. We’ll see the different types of combo chart in this lesson.
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Lesson Goal (00:10)
The goal of this lesson is to use a combo chart to combine a bar chart and a line chart in a single visualization.
Creating a Chart With Two Variables (00:25)
Bar or column charts and line charts often don’t work well when you aim to analyze variables that have significantly different values. For example, we create a column chart showing the revenue for each sub-region, and the number of users for each sub-region. Each sub-region has millions of dollars of revenue but only thousands of users. This makes the columns for the number of users in each sub-region difficult to read and analyze.
Creating a Combo Chart (01:15)
A combo chart is a chart that combines a column chart and a line chart on a single visualization. When creating a line chart, the column values well is used for the field that determines the values of the column chart, while the line values well is used for the field that determines the values of the line chart.
The column chart and line chart each have their own vertical axis, which makes the combo chart ideal when analyzing two fields that are measured with different numeric scales.
The column chart in a combo chart can be either a stacked column chart or a clustered column chart. The column series well is used for the field that is used to create a legend in the column chart. If you find that the clustered column chart contains columns that are too narrow, this can sometimes be improved by switching to a stacked line chart.
So far, we've looked at two main chart families: bar charts, and line charts.
In this lesson, we use a combo chart to combine a bar chart and a line chart in a single visualization.
To illustrate why this can be useful, let's create a new page in our report and name it 'Combo Charts'.
Suppose we want to examine the relationship between the revenue generated and number of users. Specifically, we want to see if there are any differences in revenue generated per user, between the different parts of the country. This time, we'll analyze it at the sub-region level. We'll start by creating a new chart of revenue by sub-region.
Next we'll add the number of users to the Values well and enlarge the chart.
We can see that the bars for users are far too small to be useful.
This is because each sub-region has several million dollars of revenue, but at most 127,000 users. A single numeric axis simply does not work for both variables.
To fix this, we'll create a combo chart.
We can combine a line chart with a stacked or a clustered column chart.
We'll select line and clustered column chart.
If we look at the field wells, we can see that we now have the option of Column Values and Line Values.
We'll drag the number of users to the Line Values well, and see that the number of users becomes a line with its own Y-axis on the right side of the visualization.
We can now easily compare the revenue and number of users by sub region.
It's immediately clear that both line and columns follow a very similar trend implying there is no major difference in the average revenue per user, by sub region.
If we look back over at the Visualizations pane, we can see that there's a new well called Column Series.
This effectively functions as a legend for the column chart. Let's drag the State field to this well.
The column chart is clustered by state, however it's not that easy to read.
Unfortunately, Power BI determines the width of each column, according to the total number of different values in the model.
This means that the column width is determined by the total number of states, not the number of states in each sub region.
To make this chart easier to understand, let's switch to a line and stacked column chart.
This switches the column chart to a stacked chart, similar to what we've seen in previous lessons. If you find clustered column charts produce columns that are too narrow, then switching to a stacked column chart like this may help.
As we can see the combo chart is useful when you want to compare variables with different scales on a single visualization.
We've now learned how to combine a line chart and a column chart using a combo chart.
In the next lesson, we'll learn about the ribbon chart, which also combines elements of a line chart and a column chart.