
Sinusoidal projection
A 'sinusoidal projection' is a pseudocylindrical equal-area
map projection, sometimes called the 'Sanson-Flamsteed' or the 'Mercator equal-area projection'.
The north-south scale is the same everywhere at the central
meridian, and the east-west scale is throughout the map the same as that; correspondingly, on the map, as in reality, the length of each parallel is proportional to the cosine of the latitude; thus the shape of the map for the whole earth is the area between two symmetric rotated cosine curves. The true distance between two points on the same meridian corresponds to the distance on the map between the two parallels, which is smaller than the distance between the two points on the map. There is no distortion on the central meridian or the
equator.

A sinusoidal projection shows relative sizes accurately, but distorts shapes and directions. Distortion can be reduced by "interrupting" the map.
Similar projections which wrap the east and west parts of the sinusoidal projection around the
north pole are the
Werner and the intermediate
Bonne and
Bottomley projections.
External links
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Cybergeo article
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Image Projections - Interactive visual comparison between the sinusoidal projection and other types, for use in panoramic photography.
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Table of examples and properties of all common projections, from radicalcartography.net