Re: [R] Adding percentage to Pie Charts (was (no subject))

From: Anupam Tyagi <AnupTyagi_at_yahoo.com>
Date: Tue 19 Sep 2006 - 06:51:51 GMT

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. Received on Tue Sep 19 18:28:26 2006

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.1.8, at Tue 19 Sep 2006 - 08:30:05 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.