How can I tell if NumPy creates a view or a copy?

For a minimal working example, let's digitize a 2D array. numpy.digitize requires a 1D array:

import numpy as np
N = 200
A = np.random.random((N, N))
X = np.linspace(0, 1, 20)
print np.digitize(A.ravel(), X).reshape((N, N))

Now the documentation says:

... A copy is made only if needed.

How do I know if the ravel copy it is "needed" in this case? In general - is there a way I can determine if a particular operation creates a copy or a view?