This video will show you how to make dual-axis combination charts – or combo charts – in Tableau and three different ways to use them.
This is Ryan with Playfair Data TV. And in this video, I’m going to show you how to make dual axis combination charts as well as a couple of creative applications of this chart type.
To begin, let’s make a dual axis combination chart. We’re going to make this starting out with our sales metric. So I’m going to doubleclick Sales. And I’m going to break that down by year of order date. So I’ll just doubleclick Order Date, because I know that the default date part is year.
I’m now going to add a second row to this. So I’m going to break down a second measure. And we’ll do Profit Ratio in the Sample Superstore data set. So I’m going to drag Profit Ratio to the second row.
Because we’ve got two measures on the rows shelf, they each get their own set of marks cards over here. And what’s important about that is we can modify them individually. So for example, on the first row, we could have a mark type of bar, and on the second row, we could keep that mark type of line.
There are several ways to make a dual axis combination chart. The way that most people learn, and what’s probably most intuitive, is to just to click into the second measure on the rows shelf and click Dual Axis.
That’s the first method. I’m going to click Undo and show you how to save one click. If you hover over the second y-axis, a green triangle will appear in the top left corner of that axis. You can click and drag on that triangle, and it’s moving the axis. So as I move my mouse over to the right and towards the right side of the bar chart, that dashed line that appears is showing me where the axis will be dropped. If I drop it there, same thing. We’ve got a dual axis combination chart.
I can take this a step further. I can put in another breakdown, maybe by category and then year. So I’ll put Category first. And now I’ve got a dual axis combination chart breaking down my sales as well as profit ratio measures by category first and then year of order date.
So that’s how they’re done. This is one of my top three techniques for all of my favorite tricks in Tableau. I always say that if you can really get good at dual axis combination charts, parameters, and calculated fields, it unlocks a lot of flexibility in Tableau. So this will be a really important tactic for you to know.
And in fact, the next application that I’m going to show you takes advantage of all three of those things. So I’m going to show you a different dashboard just to point out one application of a dual axis combination chart. I’ve used it in this case to make my end user part of the story. This dashboard looks at household income ranks. And we’ve got that on the y-axis. On the x-axis is the percentile rank. So most people think of 99th percentile as the best rank. I basically flip that. So if you’re number one rank, that means you’ve got the highest annual household income.
Most people, when you come across this, maybe some data journalists would post it like this, you might just see this curve just showing you the data. I’ve taken it a step further in Tableau by making my end user part of the story through these three tactics, parameters, calculated fields, and dual axis combination charts. It sounds like a lot, but it’s fairly simple.
What’s happening is I’ve got a parameter here. And as you change this slider to a different number, there’s a calculated field that just says if the parameter selection matches the value on the y-axis, then show that circle on the view. But this is actually a dual axis combination chart.
Remember, you can always reverse engineer Tableau public visualizations by downloading them from the web. And if the sheets are hidden, which they are in this case, just click on the sheet and click this icon. That’ll take you to the underlying sheet, and you can also see the underlying data.
So here’s the calculated field I was referencing earlier. If you see an equal sign, you can right-click on that field, and click Edit, and you can see exactly how the formula was written. It says if the annual household income value matches the selection in this parameter, then show the value. So you only see one value per selection.
But the secret sauce here is the dual axis. I’ve hidden it right now. But I can show it to you by right-clicking on Calculation 1 and clicking Show Header. So there’s the two axes. Just like the first example we built. It’s just that our mark types are different. We’ve got a mark type of line for the left axis and a mark type of circle for the right axis.
I’ll show you one more application of these. It’s a pretty simple technique that I think will really improve the design of your line graphs. I’ll start by just creating a quick sales by continuous month trend. And a lot of people like to add markers to a line graph. That’s an effect on the color marks card. If I click Color, one of the effects is called markers. And if I choose this option in the middle, it’ll add a little circle to every data point.
Big drawback with these, though, is that what you see is what you get. There’s absolutely no formatting flexibility. So that’s what I’m going to show you with this last technique using a dual axis combination chart. We’re going to provide the ability to format those circles a little bit.
I’m going to start by adding Sales to the second row. Now that we’ve got two measures on the rows shelf, they each have their own set of marks cards, which can be edited independently of each other. So on the second row, I’ll change the mark type to Circle. I’ll convert this to a dual axis combination chart using one of the two techniques I showed you earlier in this video. Just click into the second pill on the rows shelf and click Dual Axis.
To ensure these are lined up properly, you can right-click on either axis and click Synchronize Axis. You saw a little tiny shift there. We now know for sure that these are lined up.
But what’s nice about this now is those circles can be modified however we want. So essentially we’re formatting the markers. Obviously, you can’t do this if you’re using the second axis for another purpose. But in this case, we’re not. This is purely just to improve the formatting of a line graph.
I can now make the size of those circles larger if I wanted to. I could change the color of them. The color could be based on whether it’s a positive improvement or a negative decline. There’s all kinds of applications for this. But if you get good at dual axis combination charts, you’ll find there’s a lot of applications. And I think you’ll really get a lot out of these.
This has been Ryan with Playfair Data TV – thanks for watching!