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

Hi Frank,

> 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.

See Ugo's message about making bar graphs at:

You may be able to translate this logic into VisAD-Python.

> 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?

The Shape logic may help you do this. This logic is accessible
from VisAD-Python as described at:

Good luck,
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738