Greg Snow <Greg.Snow <at> intermountainmail.org> writes: > > You may want to rethink your whole approach here: > > 1. Pie charts are usually a poor choice of graph, there are better > choices. > 2. Adding percentages to a pie chart is a way of admitting that the pie > chart is not doing the job. > 3. If you want people to compare percentages, then a table is what is > needed. > 4. A pie chart with percentages added is essentially a colorful but > poorly layed out table. > > Consider using a dotplot instead of a pie chart, it changes the job of > the viewer from comparing areas/angles (done poorly by humans) to > comparing positions along a common scale (done well by humans).
I think dot charts (plots) are very useful, but they are not substitutes for a pie chart: they do not show a comparison between the total and the individual value; have a different scale (linear, usually), and are visually not suitable to answer some questions that a pie chart can answer (is the value approximately less than a fourth of the total? Is it less than half?). For some of these questions, even dot-charts require a value label, or the user doing mental calculations to guess approximations. I think I am quite attuned to getting approximate fractions from a pie-chart in shorter time, than on a linear scale like the dot-chart. A modification in a pie chart that draws overlapping areas with a common start point at the top of the circle, can make is more informative than a dot-chart. Something like: * Start drawing at the top of the circle, as zero (degree/area). * Draw the representation of every value starting from the top, as zero, representing it as a labled line from the center of the circle to the boundary (can use colors where possible). * Use two lables for the circular axis, inside one for percentages, outside for values. What is the simplest way to draw this in R? Anupam. ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
