x and y axis through (0,0)

Thanks for the suggestion I've now got lines through the

    > origin. Do you know of anyway to add tick marks and labels
    > to those lines? David

There is no built-in support for this currently, you would have to
draw the ticks and tick labels yourself (eg with the TICKLEFT,
TICKRIGHT, TICKUP, TICKDOWN linestyles). Making axis and tick
placement much more flexible is a high priority and is listed under
the "Axis autoranging and tick customization" section of the goals
page at http://matplotlib.sourceforge.net/goals.html.

Feel free to file a support request on
http://sourceforge.net/tracker/?group_id=80706&atid=560721 to help us
track this issue.