Bonne projection
Encyclopedia
A Bonne projection is a pseudoconical equal-area map projection
, sometimes called a dépôt de la guerre or a Sylvanus projection. Although named after Rigobert Bonne
(1727–1795), the projection was in use prior to his birth, in 1511 by Sylvano, Honter in 1561, De l'Isle before 1700 and Coronelli in 1696.
The projection is:
where
and φ is the latitude, λ is the longitude from the central meridian, and φ1 is the standard parallel of the projection.
Parallels of latitude are concentric circular arcs, and the scale is true along these arcs. On the central meridian
and the standard latitude shapes are not distorted.
Special cases of the Bonne projection include the sinusoidal projection
, when φ1 is zero, and the Werner projection
, when φ1 is π/2. 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
Map projection
A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane. Map projections are necessary for creating maps. All map projections distort the surface in some fashion...
, sometimes called a dépôt de la guerre or a Sylvanus projection. Although named after Rigobert Bonne
Rigobert Bonne
Rigobert Bonne was one of the most important cartographers of the late 18th century.In 1773 Bonne succeeded Jacques Nicolas Bellin as Royal Cartographer to France in the office of the Hydrographer at the Depôt de la Marine. Working in his official capacity, Bonne compiled some of the most detailed...
(1727–1795), the projection was in use prior to his birth, in 1511 by Sylvano, Honter in 1561, De l'Isle before 1700 and Coronelli in 1696.
The projection is:
where
and φ is the latitude, λ is the longitude from the central meridian, and φ1 is the standard parallel of the projection.
Parallels of latitude are concentric circular arcs, and the scale is true along these arcs. On the central meridian
Meridian (geography)
A meridian is an imaginary line on the Earth's surface from the North Pole to the South Pole that connects all locations along it with a given longitude. The position of a point along the meridian is given by its latitude. Each meridian is perpendicular to all circles of latitude...
and the standard latitude shapes are not distorted.
Special cases of the Bonne projection include the sinusoidal projection
Sinusoidal projection
The sinusoidal projection is a pseudocylindrical equal-area map projection, sometimes called the Sanson–Flamsteed or the Mercator equal-area projection. Jean Cossin of Dieppe was one of the first mapmakers to use the sinusoidal, appearing in a world map of 1570...
, when φ1 is zero, and the Werner projection
Werner projection
The Werner projection is a pseudoconic equal-area map projection sometimes called the Stab-Werner or Stabius-Werner projection. Like other heart-shaped projections, it is also categorized as cordiform...
, when φ1 is π/2. The Bonne projection can be seen as an intermediate projection in the unwinding of a Werner projection
Werner projection
The Werner projection is a pseudoconic equal-area map projection sometimes called the Stab-Werner or Stabius-Werner projection. Like other heart-shaped projections, it is also categorized as cordiform...
into a Sinusoidal projection
Sinusoidal projection
The sinusoidal projection is a pseudocylindrical equal-area map projection, sometimes called the Sanson–Flamsteed or the Mercator equal-area projection. Jean Cossin of Dieppe was one of the first mapmakers to use the sinusoidal, appearing in a world map of 1570...
; an alternative intermediate would be a Bottomley projection