slowdown when using pcolor and TkAgg; help?

My guess is that the hold mode is true (that's the

    > default). I think this means that every time you call
    > .pcolor that you are just appending another one to the
    > axes. You should either change the default hold mode or
    > call the .clear() method of the axes object before calling
    > the .pcolor method. If you don't do that it is rendering n
    > previous versions and the time it takes grows linearly.

Good catch Perry. You need

sp.hold(False)

    >> P.S. At risk of distracting from the main problem: I am not
    >> entirely sure I'm commanding a redraw in the correct
    >> fashion. I'm fuzzy on the difference between show and
    >> plot. Using canvas.show() and canvas.plot() both seem to
    >> work. Just calling plot() doesn't. Any hints on this or
    >> pointers to documentation would be appreciated.

Se http://matplotlib.sourceforge.net/faq.html#SHOW

    >> Also, is pcolor documented anywhere?

From the python shell

  In [1]: fig = figure()
  In [2]: sp = fig.add_subplot(111)
  In [3]: help(sp.pcolor)

All the class docs can be found at
http://matplotlib.sourceforge.net/classdocs.html. In particular,
http://matplotlib.sourceforge.net/matplotlib.axes.html#Axes-pcolor

    >> ----- the code -----

Your code was improperly line wrapped and hence I had to edit it to
test it. Please check that when you paste code in, it does not
improperly wrap.

Hope this helps,
JDH