[R] 2d plot with modification of plotting symbol to indicate third dimension.

[Jim Lemon]

On 01/13/2011 06:19 AM, John Sorkin wrote:
> I would like to plot 3-dimensional data on a two-dimensional scatter-plot.
> Is there a way I can automatically modify the plot symbol (e.g. changing size or color) to indicate the value of a third variable? E.g. How can I plot weight vs. age and indicate the value of muscle mass for each value weight-age pair by making the plot point proportional to the subject's muscle mass?

Hi John,
I think Greg's suggestions should do what you want, but if not, have a 
look at the example for the color.scale function (plotrix).

Jim