errorbar with one value + scatter

Dear all, Praise for this first serious python plotting

    > package!


    > I have two minor comments:

    -> when I try to do an errorbar plot with a scalar, rather than an
    > array as the argument (i.e. errorbar(scalar_x, scalar_y,
    > xerr=scalar_xerr)) I get the following error message:

    > "/usr/lib/python2.3/site-packages/matplotlib/",
    > line 569, in errorbar right = x+xerr[1] IndexError: index
    > out of bounds

    > This is due to the fact that the length of xerr is tested
    > only to be 1 or greater than 1 (asymmetric
    > errors). However, the option that I would like to plot
    > just one point is not included. So an extra if-clause is
    > needed before the present code that checks whether x and
    > xerr are arrays or not.

Well, the behavior you are seeing is the correct, documented behavior.
I think it would be easier for you to pass errorbar what it is
expecting than for errorbar to handle this additional use case - it's
already getting pretty hairy in there.

DO you have a problem doing


    -> I very much like the option for scatter to color the blobs to
    -> be
    > plotted. However, I have an application where the shape of
    > the blobs is immaterial: I would rather have filled
    > circles (or even better: filled symbols, be it circles,
    > triangles ...). Anyhow: I would like them to be symmetric
    > irrespective of the range of the axes. One option would be
    > to allow the s-keyword to be allowed to be negative, where
    > negative means: symmetric and the value of the negative
    > number being the size relative to some default size.

You're not the first! The temporary workaround is to use
plot(x,y,'o') which uses fixes sizes in points for the symbols (you
can also use '*', '+', etc) However, you cannot vary the size or
color of the symbols so this may not be workable.

When I refactor the scatter / pcolor etc commands as discussed in my
response to Dominique Orban above, I'll make sure that this case is
handled as well. I plan to support efficient handling of scatter with
arbitrary (or at least several) shapes where the size can be in data
(x,y) or user-defined coords, eg, physical sizes. It would be helpful
for me if people gave some information about how they would like
scatter to behave, particularly in regard to the sizes since I am
still working this out.

Would you like physical sizes, eg circles with radius in points, or

Should the shape depend on the aspect ratio of the plotting window.
Eg, if it's a circle and you have a short, wide window, should it
appear ellipsoidal?

What basic scatter symbols should be supported?

What are the most common uses: fixed size? fixed color? vary both?