A map is more than an instrument for the display of information. It reflects the knowledge about the earth's surface at the time of its design. Once established, it takes on a life of its own and begins to influence peoples' perceptions of the world.

Here are some famous examples of maps that dominated the view of the world for centuries:

This map of the Greek philosopher Hekataios (a German reproduction) represents the Mediterranean view of the earth at 500 B.C. Europe, Asia and Lybia (Africa) are arranged around Hekataios' birthplace Milet in the centre.

This map (a German reproduction) was made by Al Idrisi, an Arab who lived at around 1200 A.D. It places the prophet's birthplace Mecca in its centre

The London Psalter Map from the 13th century (a German reproduction) is an example of the mapping tradition of the Catholic Church. It puts Jerusalem and Bethlehem in the centre of the world

This map of the Italian Hieronymus Marini was produced in 1512, after the American continent became known to the Europeans. It shows a larger part of the world but keeps with the Christian tradition of placing Jerusalem in its centre.

The widespread use of maps that do not maintain fidelity of area can lead to serious errors of judgement about the true size of countries and continents.

Here is a small test of your own geographical perception of the world. How does North America compare in size with Africa ?

North America (Canada and the USA, including Alaska) is... A about half the size of Africa. B about 80% of the size of Africa. C about the same size as Africa. D about 1.2 times the size of Africa. E about 1.5 times the size of Africa.

North America (Canada and the USA, including Alaska) is about 80% of the size of Africa.

Satellite image of North America and Africa

Greenland: 0.8 million sq. miles Africa: 11.6 million sq. miles

Satellite image of Greenland and Africa

The North Hemisphere compared to the South  The North hemisphere is 18.9 million square miles.  The South hemisphere is 38.6 million square miles.

Europe compared to South America  Europe is 3.8 million square miles.  South America is 6.9 million square miles.

Africa compared to the Former Soviet Union  The former Soviet Union is 8.7 million square miles.  Africa is 11.6 million square miles.  [ [

Greenland Compared to China Greenland is 0.8 million square miles. China is 3.7 million square miles.

Mercator projection

PETERSON PROJECTION

The Peters Map and The Mercator Map

1620: The French cartographer Nicolas Sanson developed this projection, which is now named after him, from sketches left by Mercator.

1892: This projection developed by, and named after, the German cartographer Ernst Hammer has curved latitudes and longitudes. latitudeslongitudes

The Mollweide projection is found in many geography texts and atlases of today; it goes back to the German mathematician Karl Brandon Mollweide ( ).

In 1772 the German cartographer Johann Heinrich Lambert used the equator as reference latitude, i.e. he projected the earth's surface outward onto a cylinder that touches the earth at the equator.

Like all other cylindrical equal area maps Lambert's map combines three important properties: It has fidelity of area It shows north always up and east always to the right It allows cutting and pasting; a map which contains the Pacific Ocean in one piece can therefore easily be produced from the above map by combining its left and right parts:.

A major drawback is the elongated shape of the map, which makes it impractical for reproduction in books and atlases. Lambert's map therefore has found little use

Annual mean sea surface temperature, shown in Mercator projection Annual mean sea surface temperature, shown in Gall-Peters projection Which of the two maps shows a warmer ocean?

both maps are based on the same data and therefore show the same information. You can see this clearly if you note that the boundary between warm and cold, identified by the green and yellow belt between red and blue, is located at about 40°N and 40°S in both maps.