I am new to this list, so forgive me if this has been asked before. I am trying to do a radial plot and the following code does not seem to work:

# ------< START CODE >-------
import pylab
import matplotlib

fig = pylab.figure(figsize=(8,8))
ax = fig.add_axes([0.1, 0.1, 0.8, 0.8], polar=True)

ax.plot([4.189, 4.188],[41.347, 41.058], color = 'green', lw=1)
#ax.plot([4.199, 4.188],[41.347, 41.058], color = 'green', lw=1)
ax.set_rmax(80) # scale plot
# ------< END CODE >-------

When you run this, the entire background of the plot turns green. If you comment out the first "ax.plot" and uncomment the line below it, it works as expected. Any ideas as to what is going on? Is there some kind of limitation to the smallest line allowed? Thanks for any help!