The central cylindrical projection is a perspective

cylindrical map projection In cartography, map projection is the term used to describe a broad set of transformations employed to represent the two-dimensional curved surface of a globe on a plane. In a map projection, coordinates, often expressed as latitude and longitu ...

. It corresponds to projecting the Earth's surface onto a

cylinder A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infin ...

tangent to the equator as if from a light source at Earth's center. The cylinder is then cut along one of the projected meridians and unrolled into a flat map.''Flattening the Earth: Two Thousand Years of Map Projections'', John P. Snyder, Chicago University Press, 1993, pp. 106–107, . The projection is neither conformal nor equal-area. Distortion increases so rapidly away from the equator that the central cylindrical is only used as an easily understood illustration of projection, rather than for practical maps. Its vertical stretching is even greater than that of the Mercator projection, whose construction method is sometimes erroneously described equivalently to the central cylindrical's. The scale becomes infinite at the poles.''World Maps and Globes'', Irving Fisher and O. M. Miller, Essential Books, 1944, p. 46. It is not known who first developed the projection, but it appeared with other new cylindrical projections in the 19th century, and regularly finds its way into textbooks, chiefly to illustrate that this is not the way the Mercator is constructed. As with any cylindrical projection, the construction can be generalized by positioning the cylinder to be tangent to a great circle of the globe that is not the equator. This projection has prominent use in

panoramic photography Panoramic photography is a technique of photography, using specialized equipment or software, that captures images with horizontally elongated fields of view. It is sometimes known as ''wide format photography''. The term has also been applied to ...

, where it is usually called the "cylindrical projection". It can present a full 360° panorama and preserves vertical lines. Unlike other cylindrical projections, it gives correct perspective for tall objects, an important trait for architectural scenes.

Formulae

\begin
x & = R\left( \lambda - \lambda_0\right), \\
y & = R \tan \varphi.
\end

''R'' denotes the radius of the generating globe; ''φ'' is the latitude; ''λ'' is the longitude; ''λ''₀ is the longitude of the central meridian; and ''x'' and ''y'' are the mapped coordinates.

References

Map projections {{cartography-stub

Formulae

See also

References