Tableau Bitesize: Bump Charts
In this post we'll be looking at how to create a bump chart in Tableau. This can be a really cool way of showing changes in relative ranks of values over time
First off, connect to the data source attached below:
As this is a text file, Tableau has read the 'Year' field in as a value, so we will need to change the format of that first
Right click and drag the 'Year' dimension onto the 'Columns' shelf and select 'YEAR (Year)'
Next, we will want to establish our rankings, and we can do this via a table calculation. Create a calculated field called 'RANK' with the following formula
What this does is calculates the unique rank for each row ensuring that identical values are given different ranks. The 'asc' determines the sort order
Drag this field onto the 'Rows' shelf and the 'Country Name' dimension onto the 'Color' mark the nchange the view to 'Entire Viw'
Next, we will want to change how the 'RANK' field is being calculated. Right click this field (the one that's sitting on the 'Rows' shelf) and select 'Compute Using' then 'Country Name'
Now we're starting to look like we're on the way.
We want to create a dual axis chart so we can plot ots on top of the lines. Hold down Ctrl and click and drag the 'RANK' field that's on the 'Rows' shelf next again onto the 'Rows' shelf
Right click this new field and click 'Dual Axis'
Change the chart type on the second layer to 'Circle', synchronise the axis and then untick 'Show Header'
Drag the 'RANK' field onto the label for the circle chart and change the settings and formatting to get the values to fit neatly in the circles
Now the numbers might look odd (as in the above screenshot). If this is the case, then this is because the 'RANK' table calculation isn't computing using country, so just right click on that field and select 'Compute Using' then 'Country Name'
Now all we need to do is clear up the formatting (removing all of the lines and borders), then create the dashboard
Firstly, drag a text box onto the Dashboard and enter in the title, then drag in the sheet underneath it
The legend will automatically appear so you can then rearrange that as you wish, and hide the title of the sheet