Gall-Peters projection

The Peters World Map or Gall-Peters projection is an orthographic equal-area map projection of the earth. It was published in 1885 by James Gall in the Scottish Geographical Magazine and had been presented by Gall in 1855 at the Glasgow meeting of the British Association for the Advancement of Science (the BA). Other projections which are essentially the same (except for the ratio of the vertical to the horizontal axis) are the Lambert Cylindrical Equal Area, Behrmann Cylindrical Equal Area, Tristran Edwards, and Balthasart. They all use the property that the surface area of a sphere and the curved surface area of the cylinder containing it are the same.

Arno Peters, a historian, first presented his map in 1967 as a 'new invention', and promoted it as a superior alternative to the Mercator projection, which shows areas very much distorted (showing Greenland somewhat larger than Africa whereas in reality Africa is 13 times as large), because the Gall-Peters projection shows equal areas equal, thus giving the tropics their rightful place on the map. This argument was picked up by many educational institutes and such, and the Gall-Peters projection is therefore in much use. Opponents of the Peters world map now concede that Peters, who died in 2002, independently reinvented the projection. According to his obituary in The Times, he acknowledged Gall's precedent in the last years of his life, and changed its name from the Peters Projection to the Peters world map.

Professional geographers, while agreeing with Peters's arguments against the Mercator projection, also find much fault with the Gall-Peters projection because to keep the equal-area, it very much distorts shapes, extending anything near the equator in the north-south, near the poles in the east-west direction. They prefer maps that make a compromise between area and shape accuracy, or that are equal-area with less shape distortion.

One obvious distortion of the Gall-Peters projection is that it stretches Africa, which in reality is about as wide east-west as it is long north-south, but in this projection appears to be almost twice as long as it is wide.

Seven North American geographic organizations in 1989 adopted the following resolution that rejected all rectangular world maps, which include both the Mercator and the Gall-Peters projections:

"WHEREAS, the earth is round with a coordinate system composed entirely of circles, and WHEREAS, flat world maps are more useful than globe maps, but flattening the globe surface necessarily greatly changes the appearance of Earth's features and coordinate systems, and WHEREAS, world maps have a powerful and lasting effect on peoples' impressions of the shapes and sizes of lands and seas, their arrangement, and the nature of the coordinate system, and WHEREAS, frequently seeing a greatly distorted map tends to make it "look right," THEREFORE, we strongly urge book and map publishers, the media and government agencies to cease using rectangular world maps for general purposes or artistic displays. Such maps promote serious, erroneous conceptions by severely distorting large sections of the world, by showing the round Earth as having straight edges and sharp corners, by representing most distances and direct routes incorrectly, and by portraying the circular coordinate system as a squared grid. The most widely displayed rectangular world map is the Mercator (in fact a navigational diagram devised for nautical charts), but other rectangular world maps proposed as replacements for the Mercator also display a greatly distorted image of the spherical Earth."

It should be noted that there are other opinions within geography and cartography about the Peters World Map (its alternative name in some of the literature). First, some map societies, notably the North American Cartographic Information Society (NACIS) declined to endorse the 1989 resolution. Second, there are a small number of cartographers, including Brian Harley, who have written positively about it. Within geography more generally, some commentators see the cartographic controversy over the Peters world map as a sign of immaturity in the cartographic profession regarding the fact that all maps are political.

Arno Peters was the son of social activists and probably gained his lifelong concern about equality from his parents, Lucy and Bruno Peters. In 1929, when Peters was 13, the famous African-American activist and NAACP field secretary William Pickens visited the family and left a signed copy of his book Bursting Bonds. During the Second World War, Peters' father was imprisoned by the Nazis for refusing to obey their totalitarian regime. The Peters world map stands as an interesting and controversial attempt to use cartographic imagery for progressive causes.

On the screen

The "Peters projection map" was featured in the television drama, The West Wing, (Season 2, episode 16 "Somebody's Going to Emergency, Somebody's Going to Jail", see note) in which Dr. John Fallow (actor John Billingsley) fronts the (fictitious) "Organisation of Cartographers for Social Equality" to explain why Jed Bartlet as President of the United States of America should champion the use of this map in schools, because it correctly represents the size of the countries and therefore gives due prominence to countries in less developed parts of the world that are otherwise under-estimated because "size matters". (Note: The title of the episode is from a song playing as the episode opens and closes. The song is New York Minute by Don Henley.)

The map is also a favorite of military strategist Thomas Barnett, who has included it in his presentations of "The Brief" which have aired on C-SPAN in the United States.

See also

• Cartography
• Map projection
• Nautical chart
• Oblique Mercator projection
• Robinson projection
• Transverse Mercator projection

External links

• http://www.petersmap.com
• The Size of the Matter (http://timesofindia.indiatimes.com/articleshow/1124880.cms) - An article in the Times of India on why the Gall-Peters projection should be more widely used.de:Peters-Projektion

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