- What is the world map?
- history of the world map
- Parallels and meridians
- Map projections
- world map images
- continents of the world
- world oceans
We explain what the world map is, its history and what forms it can take. Also, what are projections, parallels and meridians.
What is the world map?
The world map (word inherited from medieval Latin world map, that is, "Map of the world") is a cartographic representation of the entire earth's surface, that is, it is a map of the entire world.
Depending on its shape, a world map can be called in two ways:
- Earth globe or globe, when the representation has a spherical shape and tries to reproduce the three-dimensional appearance of the planet.
- Planisphere terrestrial, when it reproduces to scale the projection of the terrestrial sphere on a plane two-dimensional, that is, in two dimensions.
The world maps are a very old tool, which is made with the purpose of serving as a guide in matters of geography and of politics, being able to serve as a basis for the elaboration of other maps, such as the political map (which shows the divisions of the countries), the physical map (which shows geographical features) and the map topographical (showing the contour lines of the relief), among many other specialized uses.
In the world maps, not only does the representation of the earth's surface appear (the continents, islands and the oceans), but also the symbols and signs of geographic use to organize, sectorize and imaginarily structure the planet. Thus, border lines, rivers and height lines are also usually drawn, in addition to parallels and meridians, the equator, etc. It is also normal to highlight the location of the cities and capital, as well as other elements that may be of particular interest.
history of the world map
The exploration of Asia and Africa brought new challenges to imagining the world.From very early times the humanity knew the usefulness and value of maps, and many of the ancient civilizations they wanted to draw the most accurate and exhaustive maps of the world they knew. The first attempts found at a world map date back to around 2500 BC. C., and consist of traces on Babylonian clay tablets, but were limited to the representation of the Euphrates river valley.
The ancient greeks, for their part, knew of the sphericity of the Earth and wanted to draw some kind of total map. The main pupil of Thales of Miletus, the geographer and philosopher Anaximander of Miletus (c. 610-546 BC), creator of the first map of the known world, whose appearance is unknown but in which they were represented the Mediterranean Sea, the Black Sea, the Euphrates and Phasis rivers, and three great continents: Europe, Asia and Libya, surrounded by a belt of water called the Ocean.
This first world map would serve as the basis for a much more advanced version, created by the Greek geographer and astronomer Claudius Ptolemy (c. 100-170 AD), in which he not only represented numerous rivers of the three continents known to Anaximander, but it incorporated for the first time imaginary lines longitudinal and latitudinal.
Ptolemy's world map was possibly part of his work Geography, written around 150 AD. C., but it is not preserved today. Only the reconstructions made more than 1,000 years later by Byzantine monks led by the grammarian and theologian Maximus Planudes (c. 1260-c. 1305) survive. However, the elaboration of world maps was a very common activity during the medieval European.
The subsequent exploration of Asia and Africa, just like him discovery of America, incorporated new challenges when imagining the world, which until then had been reduced to the Mediterranean Sea and its surrounding areas, always drawn in the form of a "T in O", that is, three separate continents could be distinguished in the circle of the world by the Mediterranean, forming a "T" of separation between them. These were maps uninterested in the accuracy geographical, reflecting rather theological and political ideas.
The first "scientific" world map is taken as the one drawn up by the Portuguese cartographer Diego Ribero in 1527, in which the America Y Oceania, thanks to information from explorers such as Fernando de Magallanes, Juan Sebastián Elcano and Esteban Gómez. But it would not be until the eighteenth century when new geographical projection techniques allowed the emergence of maps more similar to the current ones, which thanks to the invention of airplanes and the Photography in the coming centuries, they acquired the current accuracy.
Parallels and meridians
World maps have two main types of imaginary lines, which cross the world longitudinally and latitudinally, thus tracing a grid, useful for establishing a global system of geographic coordinates that allows orientation anywhere on the earth's surface. These imaginary lines are:
- The meridians. If we draw a semicircle that runs along the surface of the planet from the North Pole to the South Pole, we will be drawing a meridian. In other words, these are vertical lines that divide the planet into 360 spaces (“degrees”) and that allow any point on its surface to be located longitudinally. That is, we can know the longitude of any portion of the planetary surface by comparing the meridians where it begins and where it ends.
For this, it is also used a “zero” meridian of reference, which passes through the old Greenwich observatory in London, United Kingdom.From it, one degree per meridian is advanced in a positive (+1) or negative (-1) direction depending on whether it is moving east or west, respectively. These lines are used to determine the time zone.
- The parallels. If we draw a semicircle that is perpendicular to the axis of rotation of the planet and that divides it into two opposing hemispheres, we will be drawing a parallel. In other words, these are horizontal lines that allow us to locate any point on the planetary surface latitudinally, that is, we can locate the latitude from any point according to the parallels in which it begins and ends.
For this, in addition, the equator (the imaginary line that divides the world into two symmetrical hemispheres) is used as a "zero" parallel of reference. From it, we advance in sexagesimal degrees in a north (°N) or south (°S) direction depending on whether we are moving towards the northern or southern hemisphere. In addition to the equator, there are four notable parallels: the Arctic Circle (66° 33' N), the Tropic of Cancer (23° 27' N), the Tropic of Capricorn (23° 27' S), and the Antarctic Circle ( 66° 33' S). These lines serve to determine climatic zones.
Map projections
Since the Earth is not entirely spherical, nor does it really have a top and a bottom, the representations we see of it on a daily basis are not entirely exact in their proportions, but rather use scales and projection procedures to build a plausible image, that is, believable, useful, of the planet. These procedures are known as geographic projections, and throughout history there have been many of them and very different from each other.
The best known of these projections, and the most widely used today, is the Mercator projection, created by the Flemish geographer Gerardus Mercator (1512-1594) in 1569.It uses a cylinder tangent to the planet's equator as a pattern to represent the surface, which produces a necessary distortion in the length of the parallels, especially as they approach the poles.
This world map model has been criticized for being Eurocentric and making the southern hemisphere invisible, and there are numerous proposals for alternative projections, such as the one proposed by the Scottish clergyman James Gall (1808-1895) in 1855, but made more widely known by the cartographer German Arno Peters (1916-2002).
world map images
continents of the world
The six continents of the planet appear on the world map:
- Africa. It is located south of Europe and the Mediterranean Sea, between the Atlantic and Indian oceans.
- Antarctica. Located around the geographic South Pole, it is the least populated and coldest continent in the world.
- America. It is located west of Europe and Africa, separated from them by the Atlantic Ocean and also from Asia by the Pacific Ocean.
- Asia. It is located to the east of the European continent, with which it forms the same territorial mass, but separated from it culturally and politically by the Ural mountain range. It is separated from America by the Pacific Ocean and from Oceania by the Indian Ocean.
- Europe. It is located to the west of Asia, the east of America and North of Africa.
- Oceania. It is located southeast of America and south of Asia, surrounded by the Pacific and Indian oceans.
world oceans
The five oceans of the planet appear on the world map:
- Antarctic Glacial Ocean. It is located on the circumference of the South Pole, surrounding Antarctica.
- Atlantic Ocean. It is located between America and Europe to the north and America and Africa to the south.
- Glacial Arctic Ocean. It is located on the circumference of the North Pole.
- Indian Ocean. It is located south of the Indian subcontinent, between Africa, Asia and Oceania.
- Pacific Ocean. It is located between America and Asia to the north and America and Oceania to the south.