If you want to give two plot commands, and do not want the second one to wipe out the first one, do the following. plot(first plot) par(new=TRUE) plot(second plot) This will superimpose the second plot on the first. Note that the two plots may have different scales. To ensure that they […]

# Archives for **December, 2006**

John Fox’s package, “car”, has a very useful scatterplot.matrix (or simply spm) to make scatterplots of pairs from a set of variables. The plot below was created using library(“car”) scatterplot.matrix(~Exppop+Exppphc+literacy+Oppphc, reg.line=lm, smooth=TRUE, span=0.5, diagonal = ‘density’, data=temp) dev.print(jpeg, file=”~/graph-matrix.jpg”, width=500, height=500, pointsize=10)

jitter is an interesting function that adds a small noise to a vector. A very useful feature if you want to plot data points which have some ties.