Special cases of the Bonne projection include the sinusoidal projection, when φ1 is zero (i.e. the Equator), and the Werner projection, when φ1 is 90° (i.e. the North or South Pole). The Bonne projection can be seen as an intermediate projection in the unwinding of a Werner projection into a Sinusoidal projection; an alternative intermediate would be a Bottomley projection.[3]