I suspect I am not unique in not being able to remember how to control the point shapes in R. Part of this is a documentation problem: no package ever seems to write the shapes down. All packages just use the “usual set” that derives from S-Plus and was carried through base-graphics, to grid, lattice and ggplot2. The quickest way out of this is to know how to generate an example plot of the shapes quickly. We show how to do this in ggplot2. This is trivial- but you get tired of not having it immediately available.
library(ggplot2) ggplot(data=data.frame(x=c(1:16))) + geom_point(aes(x=x,y=x,shape=x))
Or if you are feeling more daring:
ggplot(data=data.frame(x=c(1:16))) + geom_point(aes(x=x,y=x,shape=x)) + facet_wrap(~x,scales='free')