Gerardus Mercator (5 March 1512 – 2 December 1594) was a 16th-century geographer, cosmographer and cartographer from the County of Flanders. He is most renowned for creating the 1569 world map based on a new projection which represented sailing courses of constant bearing (rhumb lines) as straight lines—an innovation that is still employed in nautical charts.
Mercator was one of the pioneers of cartography and is widely considered the most notable figure of Netherlandish school of cartography in its golden age (approximately 1570s–1670s). In his own day, he was a notable as maker of globes and scientific instruments. In addition, he had interests in theology, philosophy, history, mathematics and geomagnetism. He was also an accomplished engraver and calligrapher. Unlike other great scholars of the age he travelled little and his knowledge of geography came from his library of over one thousand books and maps, from his visitors and from his vast correspondence (in six languages) with other scholars, statesmen, travelers, merchants and seamen. Mercator's early maps were in large formats suitable for wall mounting but in the second half of his life, he produced over 100 new regional maps in a smaller format suitable for binding into his Atlas of 1595. This was the first appearance of the word Atlas in reference to a book of maps. However, Mercator used it as a neologism for a treatise (Cosmologia) on the creation, history, and description of the universe, not simply a collection of maps. He chose the word as a commemoration of the Titan Atlas, "King of Mauretania", whom he considered to be the first great geographer.
A large part of Mercator's income came from sales of his terrestrial and celestial globes. For sixty years they were considered the finest in the world and were sold in such great numbers that there are many surviving examples. This was a substantial enterprise involving the manufacture of the spheres, printing the gores, building substantial stands, packing, and distributing all over Europe. He was also renowned for his scientific instruments, particularly his astrolabes and astronomical rings used to study the geometry of astronomy and astrology.
The Mercator projection is a cylindrical map projection presented by Flemish geographer and cartographer Gerardus Mercator in 1569. It became the standard map projection for navigation because it is unique in representing north as up and south as down everywhere while preserving local directions and shapes. The map is thereby conformal. As a side effect, the Mercator projection inflates the size of objects away from the equator. This inflation is very small near the equator but accelerates with increasing latitude to become infinite at the poles. So, for example, landmasses such as Greenland and Antarctica appear far larger than they actually are relative to landmasses near the equator, such as Central Africa. As in all cylindrical projections, parallels and meridians on the Mercator are straight and perpendicular to each other. In accomplishing this, the unavoidable east–west stretching of the map, which increases as distance away from the equator increases, is accompanied in the Mercator projection by a corresponding north–south stretching, so that at every point location the east–west scale is the same as the north–south scale, making it a conformal map projection. Conformal projections preserve angles around all locations.
Because the linear scale of a Mercator map increases with latitude, it distorts the size of geographical objects far from the equator and conveys a distorted perception of the overall geometry of the planet. At latitudes greater than 70° north or south the Mercator projection is practically unusable, because the linear scale becomes infinitely large at the poles. A Mercator map can therefore never fully show the polar areas.
The Mercator projection maps all lines with constant bearing (rhumbs (mathematically known as loxodromes—those making constant angles with the meridians) to straight lines. The two properties, conformality and straight rhumb lines, make this projection uniquely suited to marine navigation: courses and bearings are measured using wind roses or protractors, and the corresponding directions are easily transferred from point to point, on the map, with the help of a parallel ruler.
Examples of size distortion
Antarctica appears to be extremely large. If the entire globe were mapped, Antarctica representation would inflate infinitely. In reality, it is the second smallest continent, being just smaller than Russia.
Ellesmere Island on the north of Canada's Arctic archipelago looks about the same size as Australia, although Australia is over 39 times as large. All islands in Canada's Arctic archipelago look at least 4 times too large, and the more northern islands look even larger.
Greenland appears the same size as Africa, when in reality Africa's area is 14 times as large.
Greenland's real area is comparable to the Democratic Republic of the Congo's alone.
Africa appears to be roughly the same size as South America, when in reality Africa is more than half again as large.
Svalbard appears to be larger than Borneo, when, in reality, Borneo is about 12 times as large as Svalbard.
Alaska appears to be the same size as Australia, although Australia is actually 4½ times as large.
Alaska also takes as much area on the map as Brazil, whereas Brazil's area is nearly 5 times that of Alaska.
Madagascar and Great Britain look about the same size, while Madagascar is actually more than twice as large as the largest of the British Isles.
Sweden appears much larger than Madagascar. In reality they are similarly sized.
Russia appears bigger than the whole of Africa, or North America (without the latter's islands). It also appears twice size of China and the contiguous United States combined, when, in reality, the sum is comparable in size.
The northern inflation acutely distorts Russia's shape as well, making it appear much taller north-to-south and greatly stretching its arctic regions compared to its mid latitudes. Wikipedia
