Mastering Matplotlib 2.x

Plotting vector fields

First, though, we will generate a standard Gaussian random field so that we have a nice gradient:

# Generate a vector field with a gradientfrom scipy.ndimage.filters import gaussian_filterx = np.arange(0,10,0.5)y = np.arange(0,10,0.5)phi = gaussian_filter(np.random.uniform(size=(20,20)), sigma=5)plt.subplot(141)plt.imshow(phi, interpolation='none')plt.title(r'$\Phi$')plt.subplot(142)plt.imshow(np.gradient(phi)[0], interpolation='none')plt.title(r'$\partial_x\Phi$')plt.subplot(143)plt.title(r'$\partial_y\Phi$')plt.imshow(np.gradient(phi)[1], interpolation='none')plt.subplot(144)plt.title(r'$\|\nabla \Phi\|$')plt.imshow(np.linalg.norm(np.gradient(phi), axis=0), interpolation='none')plt.gcf().set_size_inches(8,4)

Following ...