- Bonne projection
A Bonne projection is a pseudoconical equal-area
map projection , sometimes called a dépôt de la guerre or a Sylvanus projection. Although named afterRigobert 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 ["Flattening the Earth: Two Thousand Years of Map Projections", John P. Snyder, 1993, pp.60-62, ISBN 0-226-76747-7] .The projection is:
:x = ho sin E,:y = cot phi_1 - ho cos E,
where
:ho = cot phi_1 + phi_1 - phi,:E = frac {lambda cos phi} { ho}
and phi, is the latitude, lambda, is the longitude from the central meridian, and phi_1, is the standard parallel of the projection [ [http://pubs.er.usgs.gov/usgspubs/pp/pp1395 "Map Projections - A Working Manual"] , USGS Professional Paper 1395, John P. Snyder, 1987, pp.138-140] .
Special cases of the Bonne projection include the
sinusoidal projection , when phi_1, is zero, and theWerner projection , when phi_1, is pi / 2,.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.
References
External links
* [http://www.cybergeo.eu/index3977.html Cybergeo article]
* [http://exchange.manifold.net/manifold/manuals/5_userman/mfd50Bonne.htm Bonne Map Projection (manifold.net)]
* [http://www.radicalcartography.net/?projectionref Table of examples and properties of all common projections] , from radicalcartography.net
* [http://www.uff.br/mapprojections/Bonne_en.html An interactive Java Applet to study the metric deformations of the Bonne Projection]
* [http://mathworld.wolfram.com/BonneProjection.html Bonne Projection (wolfram.com)]
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