plot - Control the size of points in an R scatterplot?

Question

In R, the plot() function takes a pch argument that controls the appearance of the points in the plot. I'm making scatterplots with tens of thousands of points and prefer a small, but not too small dot. Basically, I find pch='.' to be too small, but pch=19 to be too fat. Is there something in the middle or some way to scale the dots down somehow?

Answer 1

Try the cex argument:

?par

• cex
  A numerical value giving the amount by which plotting text and symbols should be magnified relative to the default. Note that some graphics functions such as plot.default have an argument of this name which multiplies this graphical parameter, and some functions such as points accept a vector of values which are recycled. Other uses will take just the first value if a vector of length greater than one is supplied.