'Converts spherical polar coordinates to 3D rectangular cartesian
coordinates.'

def to_cartesian(self):

    x = (np.cos(self.lat) * np.cos(self.lon))
    y = (np.cos(self.lat) * np.sin(self.lon))
    z = np.sin(self.lat)
    return CartesianRepresentation(x=x, y=y, z=z, copy=False)
