I'm wondering if there is any way to make plots with open symbols, e.g.
a circle. I know how to use markers that look open, e.g. by doing
They are white in the center, but they're not really open since they
block out whatever is behind them. I tried using a color with
transparency, say alpha=0.1 or something (mfc=(1.,1.,1.,0.1)) but that
didn't work. What I have in mind is illustrated in the attached plot,
which I made some time ago in IDL. Is there an easy way to define your
own markers for plotting?