A sinusoidal projection is a pseudocylindrical equal-area map projection, sometimes called the Sanson-Flamsteed or the Mercator equal-area projection. Image File history File links Please see the file description page for further information. ... Image File history File links Please see the file description page for further information. ... The Mercator projection shows courses of constant bearing as straight lines. ...
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. On the earth, a meridian is a north-south line between the North Pole and the South Pole. ... The equator is an imaginary circle drawn around a planet (or other astronomical object) at a distance halfway between the poles. ...
A sinusoidal projection shows relative sizes accurately, but distorts shapes and directions. Distortion can be reduced by "interrupting" the map.
Conical projections — projections in which the parallels are depicted by concentric circles, and the meridians by straight lines orthogonal to them, where the angles between the latter are proportional to the differences of the corresponding longitudes (see Fig.
Azimuthal projections — projections in which the parallels are depicted by concentric circles, and the meridians by their radii, where the angles between the latter are equal to the differences of the corresponding longitudes (see Fig.
Pseudo-conical projections — projections in which the parallels are depicted by concentric circles, the central meridian by a straight line, and the remaining meridians by curves symmetric with respect to the image of the central meridian (see, for example, Fig.
On this projection, parallels of latitude are equally spaced along meridians, the distance between parallels being equal to the arc length between parallels on the generating globe.
Like the Sinusoidalprojection, distortion is minimal near the intersection of the Equator and the central meridian and increases toward the edges of the map.
The homolonsine projection is a hybrid projection formed by using a Sinusoidalprojection between 40o 44' N and 40o 44' S. A Mollweide projection is used for areas outside this range.
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