September 1, 2010
Tableau Tip: Shading an AreaTime Magazine (I can't recall exactly which) there was a discussion contrasting economic indicators that show we're in a Bear market against other indicators which show we're in a Bull market.
The first, which supports the notion that we're in a Bear market, looks like the following:
The second, which supports the notion that we're in a Bull market, looks like the following:
The image that I found most interesting and wanted to duplicate in Tableau is the Manufacturing trend show in the middle of the Bull market graphic. Here it is enlarged:
A couple of things I noticed:
- The vertical axis does not start at zero, which can mislead the reader into thinking growth is greater than it really is.
- The time frame is quite short. I understand that the purpose of the chart is to indicate recent growth, but it prohibits the reader from making any comparisons to the past.
- The shaded areas draw the reader's eyes to the times of growth. This is a very good used of shading and provided me the challenge to reproduce the shading of just these areas in Tableau.
Here's how I did it.
First, I created the line chart you see below (I won't go into each of the individual steps).
The important part of this step is to add a Reference Band with the following settings, which provides the shading of everything between the axis (50% and above indicate growth) and the line.
The key settings are:
- It must be a Band.
- The band must be from a constant to the ISM index value so that only the areas between the line and 50% are shaded.
The trick to shading only the growth areas is to add a Reference Line with the following properties:
The key settings are:
- It must be a Line.
- The line must be based on the constant 50. Again, this is the trigger point for a bear or bull market.
- The fill below the line must be white (or whatever color you have set as your background).
And viola, only the growth areas are shaded.
Of the issues I saw, here's what I fixed:
- The vertical axis now starts at zero.
- The time frame extends back 10 years. Notice that in this extended time frame, it's quite evident that there was a LONG growth period from July 2003 through November 2007. We've been in a recession since.
If you would like to play with the workbook yourself, you can download it here. There are many more measures/indicators to use in your analysis. Let me know what else you find; post your analysis as a comment.