I understand there have been studies showing people don't estimate angles as well as linear distances but people go too far out of their way to avoid pie charts when parts within whole data is shown. The 1D mosaic plot is effectively a stacked bar chart but there I suspect there is also some bias given toward the largest component such that the relative proportions of the smaller components are not well discriminated.

Stephen Few has an excellent overview of why pie charts should be avoided: http://www.perceptualedge.com/articles/visual_business_intel...

Neither pies nor mosaic charts should be used if you need exact readings of the data --- though mosaic plots do have the advantage of being rectangular, making segments much easier to label with values than the segments of pie charts.

I disagree partly. It's easier to estimate relative shares of a total from a pie chart compared to his linear examples.

I am also not so convinced. I still like a simple pie-chart.

This is a neat and natural idea. I'm actually sort of surprised I haven't seen something like this before. It's one of those things that you think "oh I could have thought of that," but then nobody does until now :)