Visualization is the main advantage of Tableau, with various chart type involve either one or two measure values, how to handle overlapping information is a big part of viz building.
Measure - Shared Axis
Just like the case in dimension label, we can also drag a measure label onto another measure label
it will create a shared axis as follows, where a new Measure Values label is created.
Note 1: We can continue to add as many measure labels into the Measure Values label as we want.
In a shared axis setup, multiple measures in the view are controlled by a single marks card. Though we can differentiate them by either different color, size or shape, any formatting will be done simultaneously to all values in the Measure Values label.
What if you want to have more flexible in formatting or customization?
Measure - Dual Axis
Unlike any previous cases, we can only create dual axis by drag a measure label into the shelf, rather than into the view.
The result is two separate axis in parallel horizontally (vertically if the dragged measure is placed in the Rows shelf). Notice we have three separate marks cards available now (one for all, two for individual plot)
Usually we would like to compare the measures and it is easier when they are together, so in this case we can create a Dual Axis by right click on the axis of the second plot.
For the resultant graph, it is always good practice to Synchronize Axis.
Note: In some case when the scale of the two axis are substantially different, or we are more interested in overall trend rather than the exactly value, we may not synchronize.
We notice this is pretty much identical as the shared axis graph, so why the trouble?
We can create different type of charts
Since we have the ability to format each measure individually, we can change them into different chart type
So which one is better? Which one should we use? Answer: It depends.
Advantage: Can compare more than two measures
Disadvantage: Lack the flexibility to customize
Advantage: Ability to format individual measures
Disadvantage: Only two measures
Often there is no best graph, the choice is left by the user to decide depends on the requirement, what are we trying to present and to show. But knowing both methods offer us options rather than being restricted.
So now, you should be ready to play about yourself with Tableau viz building, practice is always the best way to learn.
Looking for more guides, tips and tricks in Tableau or Alteryx? Go check out the other blog posts from the Data School.