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

Sarah Goslee sarah.goslee at gmail.com
Wed Jan 12 20:23:22 CET 2011

You don't give an example, but in general you can use a vector for cex with
the values proportional to the third variable.

Same goes for color: col can be a vector, not just a single value.

This has been discussed before on-list, and fairly recently.


On Wed, Jan 12, 2011 at 2:19 PM, John Sorkin
<jsorkin at grecc.umaryland.edu> 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?
> Thanks,
> John
Sarah Goslee

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