In business intelligence and visualization, reports are often presented in a dual-axis format, in which two independent axes are layered on top of each other. Dual-axis charts are very useful when we want to compare or try to understand the relationship between two or more continuous variables in a limited space and in one view. As an example, if we want to see revenues and profits against a category, such as region, we can use a dual-axis chart.
In this guide, you will learn how to build a dual-axis chart in Tableau.
The data to make a dual-axis chart should consist of two continuous measures against a categorical value. In this guide, we’ll be using data containing the population and ownership of dogs and cats broken down by state from the American Veterinary Medical Association. The goal is to visualize the two continuous measures,
cat population and
dog population, against the dimension
Dual-axis charts can be constructed in Tableau using the following steps:
There are 3 ways to change the mark type.
a. By changing the mark type in the mark shelf and selecting shape as bar, circle etc. b. By right clicking on the measure field and selecting mark type as bar, circle, shapes, etc. c. By right clicking on the axis and selecting the mark type as bar, circle, shapes, etc.
The chart above compares the cat population (represented by the bar chart), and the dog population (represented by the line chart).
The dual axes make the comparison much easier as the cat and dog populations are depicted in just one chart against the dimension of location. For example, it is easy to infer form the chart that the ratio of cats to dogs is higher in Florida than in Georgia, where there are more dogs than cats.
In this guide, you learned about building a dual-axis chart in Tableau. Such charts are extremely powerful and recommended for people who have good data interpretation and visualization skills. There are many other charts in Tableau for graphical representation that also use dual axes, such as donut charts, lollipop charts, and bar-in-bar Charts.