The Pie-Doughnut Combination: A Radial Treemap
I stumbled into this graph some years ago, while looking up data for a project on US Auto Sales, through a post in Neoformix - Discovering and Illustrating Patterns in Data. So, when I started making the list of Pie-Doughnut combination charts, I decided to include this variety and use it to display survivors and victims of the Titanic tragedy on its centenary year.
It is not a particularly difficult chart to create, specially if one sets up the table properly. My first attempt brought me this:
I thought a lot over whether to keep the statistics as labels for the outermost doughnut that displayed the survivor/victim proportions. They get a bit muddled up around the first class women and children' section and the inability to add leader lines to the doughnut labels meant they couldn't be dragged away and the lines used as pointers.