Making use of Area Charts in V7

Tableau Software are soon to release version 7 of their award winning data analysis software.  This version introduces two significant new visualisation types – Area Charts and Filled Maps.

In this post, I take a look at the ways I plan to take advantage of Area Charts once V7 is released – currently scheduled for mid Jan 2012

The standard area chart

With the right data set, the use of a standard area chart can be a reasonably good way to show the how both the total of a measure is varying, and how the measure is broken down by a single category.  In the example below, total sales is broken up into two regions.

A simple update to this chart changes its use – by choosing not to stack the colours on top of one another, we can make a reasonable job of comparing the two regions.  The areas of orange give a good impression of the magnitude by which one region exceeded the other during some periods.

Percent of total area charts

Area charts work well when looking at % of total variation over time.  In the example below, the same sales data as in previous examples is used, but the % of total is shown rather than the absolute amount.  These charts are easy to achieve using Tableau’s TABLE CALCULATION functionality – read how to get started with this here

Area charts as spark lines

Perhaps the best use of area charts is as spark lines.  The examples below show a comparison between spark lines using a simple line, and those using an area chart.

It’s hard to understand why the area chart is so much easier to read, I think is is probably because the line chart leaves so much white space.

I’m sure we’ll see many more creative uses of area charts once Tableau public gets a V7 refresh, but here’s how I plan to take advantage of them.

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Comments

[Andrew Marritt]

Good post.

There are two notes that I think are worth adding about area charts:

1) That they are showing an area under a curve and therefore like other area-type charts need to go to zero (this could limit their use in sparklines for example where, due to the desire to show a trend the zero on a line doesn't need to be shown.)

2) Showing the area has to make sense. As an example sales over time would make sense as the area would show total sales during the time period. Stock prices wouldn't make sense as the area under the curve doesn't reflect 'captured' prices without knowing volume.