add_subplot vs. add_axes

Is there any different between Subplots and Axes, other

    > than adding a subplot lets one use the matlab 3-digit
    > specification (e.g., 221 )?

Subplot inherits from Axes. It is the special case where your axes
like on a grid, eg 3 rows by 2 columns. An Axes is created by
defining the rectangle [left, bottom, width, height] that the Axes
occupies. Subplot simply computes these for you given the layout
you specify and the subplot parameters from the rc file. These
parameters govern things like the leftmost point of the subplots, or
the horizontal space between the rows.

Subplot also provides some helper functions like is_last_row which are
useful when creating lots-o-subplots in a loop, where you may want to
set the xlabel only for the last row

for i in range(9):
    ax = subplot(3,3,i+1)
    plot_something(i)
    if ax.is_last_row():
        ax.set_xlabel('time')

Other useful functions are is_first_col, is_first_row, is_last_col and
change_geometry.

See examples/axes_demo.py

  http://matplotlib.sf.net/screenshots.html#axes_demo

for an example which uses both subplots and axes...

JDH