As I mentioned in my original post, Exploring Excel 2013 as Microsoft’s BI Client, I will be posting tips regularly about using Excel 2013 and later. Much of the content will be a result of my daily interactions with business users and other BI devs. In order to not forget what I learn or discover, I write it down … here. I hope you too will discover something new you can use. Enjoy!
Making a cooler Excel chart by overlaying charts
This is one of the coolest techniques when creating compelling chart visualizations in Excel. The concept is to overlay one chart on another such as line chart over a bar chart which is our example. This is really helpful when showing data that has very different granularity or scale. In the example we will do below, we are going to show the number of tickets each hour of a day with the % spending on alcohol for that time period. Let’s get started.
Step 1 – Create the bar chart
We are creating a bar chart that shows the number of tickets created during each hour of the day at my fictional restaurant – Sensational Servings. In my bar chart, you can see that I added a title, removed the legend, and hid the field buttons. Here is the resulting chart.
Step 2 – Create the line chart
Next, we create a line chart that shows what % of the total ticket amount for that hour of the day was on alcoholic beverages. I will not add a title to this one and I will hide the buttons and the legend as well. I will also convert this to a line chart so we can see the trend through the day as a line.
Step 3 – Set up the line chart to be overlaid on the bar chart
In this step, we will walk through the settings that make line chart ready to overlay. In my scenario, you may have already noticed that the list of hours are different on the Y-axis. In order to overlay the charts, they must represent space that can be overlaid. In this example, we need to make sure that the Y-axis on both charts match. We expect that the X-axis will be different as we have a count and a percentage we want to compare. In most cases you need to have one of the axis represent the same values so you can compare the other. However, you may have a situation where this does not matter. As we move through the rest of the example, you can adjust to your data visualization needs accordingly.
In order to set the hours the same, we will show empty values for the Hour of the Day. (NOTE: you may need to do this with both charts to prevent unexpected results.) You can make this change in the PivotChart Options dialog on the Display tab.
Here is the result:
Here are the other changes we will make:
- Make the background transparent
- Remove the Y-axis label
- Move the X-axis label to the right side
- Remove the lines in the chart
Let’s do the labels first. To remove and move the respective labels, you can use the cross that is displayed on the upper left corner of the chart. The first change is unselecting the Primary Horizontal axis from the Axes menu. From here you click the Axis option and then go to More Options. That will open a side panel with more options from which you can make the necessary changes. On this panel, you need to open the Format Axis page. You will see an option for Labels near the bottom. To move the X-axis to the right side you need to select Low or High. This will depend on the data in your axis. The change is applied immediately so you should see the change. In the example we need to change it to High.
While leaving the format panel open, select the one of the gridlines. This will open the Format Major Gridlines menu. Select the No Line option and these will be removed. Once you have completed that, select the entire chart and set the fill to No Fill in the Format Chart Area and select No Line for the border in the same section.
As with many Microsoft products there are other ways such as ribbon commands to change fill and line options. You should explore other options to see which method is the most intuitive for you. However, the format panel has the most complete set of options which are grouped for the section of the chart you are modifying which is why I used that for most of the changes here.
Once all these formatting changes have been made you should see the Excel gridlines behind your line chart and it should look as follows:
Now the line chart is ready to be overlaid on our bar chart.
Step 4 – Overlaying the charts and finishing touches
The final step is both the simplest and most annoying. You will need to drag the line chart on to the bar chart. Making no changes here is what my initial attempt looks like.
You will notice that the axis labels from the line graph are outside the bar chart border, the line is not sized to be meaningful and the points on the line chart are not matching the Y-axis labels on the underlying chart.
Here are the steps I took to get this chart the way I wanted.
- Made the bar chart wider. I did this to get the space I wanted to include the labels in the chart.
- Made the plot area on the bar chart smaller. This opened up white space on the right side for the line chart labels
- Next, I made the line chart shorter. Keep in mind that without a chart title the chart expands to fill. By reducing the height of the line chart it will fit in with the title and the labels will fit into the plot height of the bar chart.
- This step is the most painful. I lined up the points with the bars and made sure that 0% was lined up with the bottom of the bar chart. This takes patience to get it looking right.
- Finally, I changed the color of the line to read so the contrast can be easily seen.
Here is the result.
Now we can see alcoholic beverages account for much more of the overall ticket amount as the day goes one. By adding slicers for thinks like day of the week we do further analysis such as seeing if Fridays are the biggest percentage and so on.
This illustration shows one of the most common scenarios to overlay charts. Using a percentage to see a trend related to the underlying values shown in the bar chart helps understand correlation. If you use slicers on your dashboard, make sure that you connect them to both charts (if you want them both filtered by the slicer of course).