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

[Anupam Tyagi]

Greg Snow <Greg.Snow <at> intermountainmail.org> writes:

> Have you read the books by Cleveland?

I do not recall reading Cleveland's book; I have read one by Tufte. You raise
some interesting issues there. I agree with some, I could not clearly understand
some other things you mention. 

I think visual perception is aquired, in part. So if I were presenting data to
viewers who took carpentry or other such classes in highschool I may be tempted
to use dotcarts.

An interesting experiment: have kids compare pieces of pie or bread-sticks over
a dinner, and check how they do.  They should not have taken a carpentry class.
I use dot-charts, they are useful. Sometimes pie carts are useful too, because
people are so used to using and seeing them over a long time. Ofcourse, they can
be improved.

Also, it may be possible to put points of a dot-chart on a single straight line,
label them with a pointing line, and get better perception. There is poor
perception of the horizantal distance, by having to view that extra vertical
distance in a dotchart. However, it is useful to have the vertical axis in
Lattice plots, but not in stand-alone dot-charts.

Anupam.