Pie chart alternative

Pie charts are bad; they’re hard to read, particularly for small percentages. This Pornhub Insights report (SFW) has an interesting alternate type of pie chart.

pornhub-traffic-mobile2The angle of each wedge is constant, 360°/5 = 72° in this graph. It’s the radius of each wedge that conveys the data. In other words it’s basically a bar chart, but turned into a circle. That’s a nice compact layout. And it visually conveys that the numbers sum to 100%. If I measure this right the wedge radius is proportional to the square root of the value, so that the wedge area is proportional to the value. That’s more correct for visual perception. It also works well for showing a 40:1 ratio like the data above; in a linear bar chart the 1% data would only be a couple of pixels high.

I’m sure Pornhub didn’t invent this, but it’s a neat technique I haven’t picked up on before.

Update: Mike B tells me this is called a Polar Bar Chart. Or a Coxcomb chart, after no less than Florence Nightengale.