Adam Green wrote:> I am having trouble finding out how to adjust the position of labels on
> pie charts. For the small wedges, many of the labels overlap making it
> impossible to read. Is there any way to offset the labels so that they
> don't overlap?
>
Hi Adam,
There are three ways to adjust the positions of labels on a 3D pie chart
(I'm assuming it's 3D from the word "wedges". If not, the
following
should still be useful).
The first is to change the position of the sectors by the "start"
argument. Apart from being useful when very large sectors cause
problems, changing the sector positions can sometimes alleviate minor
crowding of the labels.
The second is to catch the return value of the pie3D function. This is
the radial positions at which the labels have been placed. You can then
alter this vector and pass it as the argument "labelpos". In this way
you can spread out the labels for small sectors.
Finally, you can leave out the labels when you call pie3D and manually
place labels using the "text" function. The chart is drawn on a plot
that spans -1 to 1 in both directions, so it is relatively easy to work
out where the labels should be.
A word of warning - when I read, "For the small wedges, many of the
labels...", I felt that I should say that pie charts in general, and 3D
ones in particular, are rarely successful with more than 4 or 5 sectors.
In the R-news article that included pie3D, I included a pie chart that
was very difficult for the viewer to extract the information that the
creator intended. Depending upon what is to be represented, you might
consider whether another method might be more successful.
Jim