Got any tips for drawing 2d graphs with error bars, symbols, etc?

I'm trying to create a two-dimensional display of some mass-spectrometry results (observed and theoretical). For my particular work right now, that means I'd like to create the following for each data point (x,y):

        1. a vertical line that runs from (x,0) up to (x,y)
2. a point somewhere along that vertical line (probably at the top), indicating the mean value of the signal y for that x-value. 3. two (or more) horizontal bars, one above the mean point, one below, to indicate some kind of statistics (standard deviation, percentile score, ... - basically some kind of error bar)


From Ugo's excellent tutorial, I can see how to put in the point (in 2. above) along with the lines. However, it's not clear how I can put in the vertical lines. I guess I can fulfill 1. and 3. by using subs.drawLine() function to draw the lines item by item. I'm just wondering if there isn't a more "built-in" way of doing this for the set as a whole.

Also, if I wanted to use a symbol for the point-markers in 2., is there any way for me to do that? Instead of just a dot, could I put in a 'star' (*), a cross (+) or some other textual symbol easily?

Thanks, as always,

-Frank

PhD, Computational Biologist,
Harvard Medical School BCMP/SGM-322, 250 Longwood Ave, Boston MA 02115, USA.
Tel: 617-432-3555 Fax: 617-432-3557 http://llama.med.harvard.edu/~fgibbons