Example of a Mollweide projection. In this case a map of temperature anomalies associated with global warming

Example of a Mollweide projection. In this case a map of temperature anomalies associated with global cooling

The Mollweide projection is a non-geometric map projection used for geographic maps of the world, also known as the Babinet projection, or elliptical projection. As its more explicit moniker Mollweide equal area projection indicates it sacrifices fidelity to angle and shape in favor of accurate depiction of area. It is used primarily where accurate representation of area takes precedence over shape, for instance small maps depicting global distributions. Image File history File links // Description Global annually averaged surface temperatures This figure shows the difference in instrumentally determined surface temperatures between the period January 1995 through December 2004 and normal temperatures at the same locations, defined to be the average over the interval January 1940 to December 1980. ... Image File history File links // Description Global annually averaged surface temperatures This figure shows the difference in instrumentally determined surface temperatures between the period January 1995 through December 2004 and normal temperatures at the same locations, defined to be the average over the interval January 1940 to December 1980. ... Jump to: navigation, search Global mean surface temperatures 1856 to 2004 Mean temperature anomalies during the period 1995 to 2004 with respect to the average temperatures from 1940 to 1980 Global warming describes an increase in the average temperature of the Earths atmosphere and oceans. ... Image File history File links // Description Global annually averaged surface temperatures This figure shows the difference in instrumentally determined surface temperatures between the period January 1965 through December 1975 and normal temperatures at the same locations, defined to be the average over the interval January 1937 to December 1946. ... Image File history File links // Description Global annually averaged surface temperatures This figure shows the difference in instrumentally determined surface temperatures between the period January 1965 through December 1975 and normal temperatures at the same locations, defined to be the average over the interval January 1937 to December 1946. ... Jump to: navigation, search Global cooling is a theory positing an overall cooling of the Earth and perhaps the commencement of glaciation or even an ice age. ... Jump to: navigation, search The Mercator projection shows courses of constant bearing as straight lines. ...

The projection was first published by mathematician and astronomer Karl (or Carl) Brandan Mollweide (1774 – 1825) of Leipzig in 1805 as an improvement upon the Mercator projection. It was popularized by Jacques Babinet in 1857. 1774 was a common year starting on Saturday (see link for calendar). ... 1825 was a common year starting on Saturday (see link for calendar). ... Jump to: navigation, search Map of Germany showing Leipzig Leipzig [â–¶] [ˈlaiptsɪç] (Polish; Sorbian/Lusatian: Lipsk) is the largest city in the federal state (Bundesland) of Saxony in Germany. ... 1805 was a common year starting on Tuesday (see link for calendar). ... Jump to: navigation, search The Mercator projection of the world up to a latitude of 86° N and S The Mercator projection is a cylindrical map projection devised by Gerardus Mercator in 1569. ... Jump to: navigation, search 1857 was a common year starting on Thursday (see link for calendar). ...

The Mollweide is a pseudocylindrical projection in which the equator is represented as a straight horizontal line perpendicular to a central meridian one-half its length. The other parallels are equidistant and parallel to the equator while the other meridians are equally spaced at the equator but curved to meet at the poles at increasingly distorted angles. Jump to: navigation, search The Mercator projection shows courses of constant bearing as straight lines. ... Jump to: navigation, search The equator is an imaginary circle drawn around a planet (or other astronomical object) at a distance halfway between the poles. ... Meridian is: Meridian (astronomy): an imaginary circle perpendicular to the horizon. ... The 4 main circles of latitude on Earth A circle of latitude is an imaginary east-west circle on the Earth, that connects all locations with a given latitude. ...

Thus, the meridians at 90 degrees east and west form a perfect circle, and the whole earth is depicted in a proportional 2:1 ellipse. The proportion of the area of the ellipse between any given parallel and the equator is the same as the proportion of the area on the globe between that parallel and the equator, but at the expense of shape distortion, which is significant at the corners, although not as severe as in the sinusoidal projection. Sinusoidal projection A sinusoidal projection is a pseudocylindrical equal-area map projection, sometimes called the Sanson-Flamsteed or the Mercator equal-area projection. ...

Shape distortion may be diminished by using an interrupted version. A sinusoidal interrupted Mollweide projection discards the central meridian in favor of alternating half-meridians which terminate at right angles to the equator. This has the effect of dividing the globe into lobes shape. In contrast, a parallel interrupted Mollweide projection uses multiple disjoint central meridians, giving the effect of multiple ellipses joined at the equator. More rarely, the project can be drawn obliquely to shift the areas of distortion to the oceans, allowing the continents to remain truer to form.

Because the Mollweide is a proportional ellipse, it has proved versatile in the creation of many hybrid projections, including the Goode's homolosine, the Robinson, and the Boggs. Robinson projection map (Large 2 MB). ...