I would lik to plot a sequence of data points as vertical lines topped with
either nothing, a circle, a dot or an arrow head.
This is done with the stem function in Matlab, but it is in no way related
to a stem-and-leaf plot.
It is used to plot discrete-time signals or a frequency domain discrete
spectrum.

Assuming this is possible, how can I combine this with a standard column
chart?

Thanks,
John