How to create a bump chart

What is a bump chart? When should you use it? How do you create one in Datawrapper? In this tutorial, you'll learn how to create a bump chart like the one below (taken from this blog post here): 

👉  This tutorial assumes you already know a bit about creating line charts in Datawrapper. If not, we suggest you read the following articles first: " How to create a line chart", " Customizing your line chart".

  1. What is a bump chart and when should you use it?
  2. How to create a bump chart in Datawrapper 
  3. Advanced: Use a scatter plot to add another dimension

What is a bump chart and when should you use it? 

A bump chart (or a rank chart) is a great way to show rankings, and how they changed over time. It's especially useful when you want to draw attention to change in the rankings of multiple categories rather than their values themselves. 

Use a bump chart if  ranking is important. If you want to communicate not just the ranking but other variables such as the individual values, use another chart type like a line or an area chart. Bump charts are simple by nature and usually used to compare two dimensions.

How to create a bump chart in Datawrapper 

1

Prepare the data

The dataset for the chart above looks something like this: 

One column should contain dates (in this case years) and other columns should contain the different categories you're ranking against (in this case, chart types). 

Click on the "Get the data" link at the bottom of the chart to download the full data to follow along. 

  • If your dataset is transposed, don't worry − you can transpose it after uploading the data with a click. 
  • f your dataset isn't in ranking, =RANK( ) functions in spreadsheets are useful. 
  • Your dataset should be in a wide format. 
2

Create a line chart 

Copy & paste your data in Step 1 and check that your dataset is correctly interpreted by Datawrapper in Step 2. Then proceed to  step 3: Visualize. 

Here, select " Lines" as the Chart type: 

3

Reverse the vertical axis 

Click on the Refine tab. Now, we'll reverse the vertical axis so that Rank #1 is displayed at the top instead of at the bottom. To do this, go to Vertical axis panel > Custom range and enter the range in reverse order. The trick here is to enter a number that is bigger than zero to prevent the x-axis from displaying: 

If you want to remove the grid lines as well as the labels, enter a " space" inside the Custom ticks text input and select: Grid lines - hide. 

4

Curve the lines and improve readability 

Curving the lines of your chart can improve readability by making it easier for your readers to follow each of the intertwining lines. To do so, go to Customize lines panel > Interpolation and select curved: 

Another way to improve readability is to add symbols for every data point. To do this, go to Customize symbols > check Line symbols: 

5

Increase the label margin to fit the text

Sometimes, the text labels can be quite long. To fit them inside the chart, use the Label margin slider bar. When increasing margin, make sure to check that your chart is readable on smaller screen sizes like mobile. If not, duplicate the chart to create another version for mobile/tablet screens.

Bump charts are a simple and effective way of showing ranking, but they also have downsides — especially when you want to show not just the ranking but the actual values as well. Reducing data to rankings can sometimes be misleading. One workaround for this problem is to use a scatter plot. 

Advanced: Use a scatter plot to add another dimension

The advantages of using a scatter plot compared to a line chart are outlined in more detail in the original blog post.

Here are some tips when creating a chart like this one: 

When creating a bump chart with a line chart, you're drawing the lines and then adding the symbols on top along the lines. In a scatter plot, the thinking is the opposite — you first plot the symbols, and then connect the plots by drawing lines between them. 

Plotting the symbols

To plot the symbols, your dataset should be in a long format. It should also contain the date (Years: horizontal axis), rank (Rank: vertical axis), and values (charts_published: symbol size), and a category column (chart_type: players in the ranking). 

Drawing the lines

Once your symbols are plotted, you can connect the symbols with lines. You can learn more about how to draw lines in this article " How to connect scatterplot dots with lines". 

One big advantage of using a scatter plot is the ability to customize the tooltips. With HTML and inline CSS, you can style the text, add extra information, insert charts and images, and more. Learn the details in this article " How to customize tooltips". 

If you're stuck, have any questions, notice mistakes or have better ideas, reach out to us at support@datawrapper.de.