Create a Dual Color Axis in Tableau

With Tableau 8, users gained the ability to color marks by multiple dimensions on a single axis with some automatic combined field magic. What happens though, when you want color by a dimension and a measure? In the past, I have separated out members of a dimension and allowed the specific measure I needed with a calculated field:

Western Region Sales = IF [Region] = 'West' THEN [Sales] END

This doesn't work if I have a more than a pair of items to color (Western Sales, Eastern Sales, etc). Instead, I used a technique that has been possible even before Tableau 8's addition of multiple colors. The solution also ends up being faster than creating multiple calculated fields and seemed surprisingly obvious once I had finished.

Dual Color Axis Map

Here, I have colored the states by Region, but the intensity of the color is based on the Sum of Sales. The same principle can be applied to a variety of chart types:

Dual Color Axis Bar Chart

The trick is using Dual Axis functionality along with some transparent colors. One of your axes will be colored by your relevant dimension. In the examples above with Superstore data, I have colored States by Region. I then created a Dual Axis with the relevant measure (Bar Chart is Sales, Map is Latitude).

First Axis Colored by Relevant Dimension

For help, see Dan Murray's post on building a dual axis map.

Second Axis Colored by Measure

On the Marks card, select the axis colored by sales. Then click the Color box and choose Black Sequential.  Also on the Color box, select 65% on the Transparency slider.

Transparency Slider

You should now have the visual effect of a dimension shaded by a measure value!  You will find the workbook I used attached below.  Please comment if you find other useful instances of this trick or your own solution to this problem!

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Will Jones

Analytics Consultant | Visualization Practice Lead