Pseudocylindrical projection

Pseudocylindrical projections are similar to cylindrical projections but differ in the way they handle meridians. Both projections use the basic shape of a cylinder as a Developable surface as a basis to create a map projection, as well as keeping evenly spaced Standard parallel but with pseudocylindrical projections the meridians are curved rather than straight. This often generates flat maps that appear to be pinched near the poles and rounded along the equator.



This type of projection represent the central meridian and each parallel as a single straight line segment, but not the other meridians. Each pseudocylindrical projection represents a point on the Earth along the straight line representing its parallel, at a distance which is a function of its difference in longitude from the central meridian. Because the meridians are not always perpendicular to the parallels, conformality is lost, leading to extreme distortion in shape at the poles. Area preservation is the goal using this map projection.

Types of Pseudocylindrical projections

 * Sinusoidal: the north-south scale and the east-west scale are the same throughout the map, creating an equal-area map. 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 region 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. The true distance between two points on the same parallel – and the true area of shapes on the map – are not distorted. The meridians drawn on the map help the user to realize the shape distortion and mentally compensate for it.


 * Mollweide


 * Eckert IV
 * [[Image:map projection-Eckert IV.png|200px]]


 * Eckert VI
 * [[Image:map projection-Eckert VI.png|200px]]


 * Foucault's Stereographic Equivalent


 * Collignon's Projection


 * The Parabolic Equal-area Projection
 * [[Image:mp_CPar-s75.png|200px]]


 * The Loximuthal Projection[]
 * [[Image:mp_Loximuthal-s75-p51.5.png|200px]]


 * The Quartic Authalic Projection
 * [[Image:Mp QuaAuthalic-s75.png|200px]]


 * Kavrayskiy's Fifth Projection
 * [[Image:Mp Kav7-s75.png|200px]]