def METHOD_NAME():
    global X_C, Y_C, Z_C, R
    # make skimage import in setup function so as not to kill complete test suite on dodgy skimage
    # FIXME - remove skimage dependency completely
    # Make a shell for coordinate testing
    from skimage import morphology
    r = 49
    ball = morphology.ball(r, dtype=int)
    SPHERICAL_SHELL = morphology.binary_dilation(ball) - ball
    X, Y, Z = np.where(SPHERICAL_SHELL)
    X_C, Y_C, Z_C = X - r, Y - r, Z - r
    R = np.sqrt(X_C**2 + Y_C**2 + Z_C**2)