Duncan Murdoch <murdoch.duncan <at> gmail.com> writes: > > On 11-10-02 1:11 PM, Kerry wrote: > > I have 3 columns of data and want to plot each row as a point in a > > scatter plot and want one column to be represented as a color gradient > > (e.g. larger values being more red). Anyone know the command or > > package for this? > > It's not a particularly effective display, but here's how to do it. Use > rainbow(101) in place of rev(heat.colors(101)) if you like. > > x <- rnorm(10) > y <- rnorm(10) > z <- rnorm(10) > colors <- rev(heat.colors(101)) > zcolor <- colors[(z - min(z))/diff(range(z))*100 + 1] > plot(x,y,col=zcolor) >
or d <- data.frame(x,y,z) library(ggplot2) qplot(x,y,colour=z,data=d) I agree about the "not particularly effective display" comment, but if you have two continuous predictors and a continuous response you've got a tough display problem -- your choices are: 1. use color, size, or some other graphical characteristic (pretty far down on the "Cleveland hierarchy") 2. use a perspective plot (hard to get the right viewing angle, often confusing) 3. use coplots/small multiples/faceting (requires discretizing one dimension) ______________________________________________ [email protected] 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.
