The Bonne projection is a pseudoconical equal-area map projection, sometimes called a dépôt de la guerre,[1]: 104 modified Flamsteed,[1]: 104 or a Sylvanus projection.[1]: 92 Although named after Rigobert Bonne (1727–1795), the projection was in use prior to his birth, in 1511 by Sylvanus, Honter in 1561, De l'Isle before 1700 and Coronelli in 1696. Both Sylvanus and Honter's usages were approximate, however, and it is not clear they intended to be the same projection.[1]: 60