Original ticket http://projects.scipy.org/numpy/ticket/1985 on 2011-11-22 by trac user gsiisg, assigned to unknown.

I notice that when I plot two variables, the x and y axis are flipped according to the online example, so I did a simple distribution of points

x=np.array([ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1])
y=np.array([ 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 100])
H, yedges, xedges = np.histogram2d(y,x)
extent = [xedges[0], xedges[-1], yedges[0], yedges[-1]]
pylab.imshow(H, extent=extent, interpolation='nearest',origin='lower',aspect='auto')

I had to enter into histgram2d() the "y" before the "x" to get the graph to come out as expected.