import pylab as pl

xlist = pl.linspace(-2.0, 2.0, 5)
ylist = pl.linspace(-2.0, 2.0, 5)
X, Y = pl.meshgrid(xlist, ylist)
print(X)
print(Y)
V= pl.sqrt(X**2 + Y**2)
print(V)

xlist = pl.linspace(-2.0, 2.0, 400)
ylist = pl.linspace(-2.0, 2.0, 400)
X, Y = pl.meshgrid(xlist, ylist)
V= pl.sqrt(X**2 + Y**2)

pl.figure()
CP1 = pl.contour(X, Y, V)
pl.clabel(CP1, fontsize=10) 
pl.title('Contour Plot')
pl.xlabel('x (cm)')
pl.ylabel('y (cm)')
pl.show()

pl.figure()
CP2 = pl.contourf(X, Y, V)
pl.colorbar(CP2)
pl.title('Contour Plot')
pl.xlabel('x (cm)')
pl.ylabel('y (cm)')
pl.show()

levels = [0.0, 0.5, 1, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0]
CP3 = pl.contour(X, Y, V, levels, colors='k')
pl.clabel(CP3, colors = 'k', fmt = '%2.1f', fontsize=14)
CP4 = pl.contourf(X, Y, V, levels)
pl.colorbar(CP4)