Reading Ian Spence's "No Humble Pie", I come across the usual criticism of the pie chart being ineffective in displaying data. As Spence writes about how many hope pie chart to be something it is not, "much of the adverse criticism of the pie has come from those who have wished it to do more than it could. The pie chart is a simple information graphic whose principal purpose is to show the relationship between a part to the whole. It is, by and large, the wrong choice as an exploratory device, and it is certainly not the correct choice when the graph maker or graph reader has a complicated purpose in mind, such as displaying small changes in proportion over time, a task would require several pies. Such a complex task can be made even more difficult if the total area of each pie varies in proportion to the changing quantities that make up 100% of each pie (Hollands & Spence, 2001)."
He also noted the pie chart above that is collected from D. F. Donnant's translation of Playfair's 1805 work, "Statistical Account of the United States of America", "This chart is unlike other Playfair pies because it contains a much larger number of segments and is decorated around the circumference. There are major tick marks at approximately the 10% positions and also minor marks at the 5% positions. Playfair has labelled the segments and also stated the actual values of the land areas in square miles on each segment."
It has me thinking if we may have missed something when we draw our pie charts today. Perhaps, the pie chart is better if it is not a circle and the edges are not so smooth so that we can identify the shaded area better using tick marks as shown in one of the original pie charts by its creator.
Inspired by Playfair's 1805 pie chart, how about a not-so-freshly baked idea? A Tart Chart:
Like the sides of a tart shell, the side of the chart is made with edges, turning it into a decagon. This marks every 10% clearly, although it does miss out on the ones in the percentage. 10 is used as it provides an easy number to count.
My first attempt at colouring it:
With the starting line being on the left, it may be hard to see where the chart starts. Hence, if we rotate the tart chart, it becomes clearer that it is 60%.
Putting 10 of them together, we can count the ones. A freshly baked Tartlet Chart that shows 86% can be seen below, as inspired by the waffle chart.
All in all, this has been a fruitful (pun intended) exercise seeing how I can sweeten the pie chart to make it possibly better loved. Nevertheless, I do not expect this to catch on, despite it solving the proportioning problem from using shaded areas on a pie chart.