import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, np.pi*4, 10)
y = np.linspace(0, np.pi*4, 10)
xx, yy = np.meshgrid(x, y)
v = np.sin(xx) + np.cos(yy)

plt.imshow(v, cmap=plt.cm.Blues, vmin=-1.5, vmax=1.5,
           extent=[x.min(), x.max(), y.min(), y.max()])
cbar = plt.colorbar(aspect=50, pad=0.08, orientation='horizontal',
                    shrink=0.6, extend='both')
plt.colorbar()