# The Mercator projection

This page is a sub-page of our page on Stereographic Projection.

Related sources of information:

Map at Wikipedia
Map projections – a video lecture GIScienceRIT at YouTube, 2 Sept 2014
The three main families of map projections at mathworld.com
Geocart Projections at www.mapthematics.com
Images for Map Projection Types at Google
Different views of the world at www.viewsoftheworld.net
Visualizing the world in different projections David Madore on YouTube, 25 Nov 2013
Worldmapper at https://worldmapper.org
The Mercator projection at Wikipedia
The man behind the Mercator projection – Stuff of Genius on YouTube
The Transverse Mercator Projection at Wikipedia
Universal Transverse Mercator (UTM) coordinate system at Wikipedia
Loxodrome (= Rhumb line) at Wikipedia
Stereographic projection at Wikipedia
Loxodromic navigation at Wikipedia
Tissot’s indicatrix at Wikipedia

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The interactive simulations on this page can be navigated with the Free Viewer
of the Graphing Calculator.

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Map projection of Earth .avi (ALAzharSEG on YouTube):

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Why all world maps are wrong (Vox on YouTube):

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The Mercator projection

/////// Quoting Wikipedia / Mercator projection:

The Mercator projection is a cylindrical map projection presented by the Flemish geographer and cartographer Gerardus Mercator in 1569. It became the standard map projection for nautical navigation because of its ability to represent lines of constant course, known as rhumb lines or loxodromes, as straight segments that conserve the angles with the meridians.

Although the linear scale is equal in all directions around any point, thus preserving the angles and the shapes of small objects (making it a conformal map projection), the Mercator projection distorts the size of objects as the latitude increases from the Equator to the poles, where the scale becomes infinite.

So, for example, landmasses such as Greenland and Antarctica appear much larger than they actually are, relative to landmasses near the equator such as Central Africa.

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Gerardus Mercator: Three ways the influential cartographer changed the way we look at the world:

Robin Show on YouTube, 5 March 2015

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The Mercator projection:

Mercator projection (first step): Projecting a loxodrome into a logarithmic spiral:

Mercator projection (second step): Mapping the logarithmic spiral into a straight line
(by exponentiating it):

Combining step 1 and step 2 to get the Mercator projection:

Reading from left to right takes you from the navigator’s map to the actual curve on the globe (the loxodrome) that it corresponds to.

Note: Unfortunately, I cannot connect the left and middle panes to the video in the pane to the right. For that I would have needed three independent panes. In that case you would have seen the points moving “in synch” in all three panes.

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History of navigation :

Majorcan cartographic school
• • Angelino Dulcert (fl. 1339)
• • Abraham Cresques (1325–1387)
• • Jehuda Cresques (1360 – 1410)
• • Catalan atlas and Abraham and Jehuda Cresques
• • Other Jewish cartographers
• • Catalan atlas

Bartolomeus Dias (c. 1450 – 1500)
• • Voyage around Africa
Vasco da Gama (c. 1460s – 1524)
• • First voyage
• • Second voyage
• • Third voyage and death

Pedro Nunes (1502 – 1578)

Christopher Columbus (1451 – 1506)
• • Geographical considerations
• • Nautical considerations

Antonio Pigafetta (c. 1491 – c. 1531)
Ferdinand Magellan (1480 – 1521)
• • Juan Sebastián Elcano (1486/1487 – 1526)

Gerardus Mercator (1512 – 1594)
John Dee (1527 – 1608)

Francis Drake (c. 1540 – 1596)

Willem Schouten (c. 1567 – 1625)
Jacob Le Maire (c. 1585 – 1616)
• • Cape Horn

History of longitude
• • John Harrison (1693 – 1776)
• • • Lunar distances versus chronometers
• • • Nevil Maskelyne (1732 – 1811)

James Cook (1728 – 1779)
• • First voyage
• • Second voyage

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Background: