plt.yticks(np.arange(0.5, 10.5), list(range(0, 10)))
plt.xticks(np.arange(0.5, 10.5), list(range(0, 10)))
plt.colorbar()
plt.gca().invert_yaxis()
plt.gca().set_aspect('equal')
plt.show()
Python Pylab pcolor options for publication quality plots