Un Planisphere it is a representation or a plan of the earth's surface that resembles a map. For that reason, it has also been given the name by which it is probably best known, which is the world map or map of the world. If you are curious to know what they are and what they are used for, we invite you to read this article.
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What is a planisphere?
Planisphere It is a word that is made up of two terms from Latin: plans, what does flat mean sphaera, which means sphere, these two terms together refer to a flat representation of the Earth, or northern hemisphere star map o celestial planisphere, because they are made on paper or some material that has a flat surface.
There is historical evidence that it was the Babylonians, around 2500 BC. C., those who in the first place were in charge of making a cartography of what at that time was thought to be the extension of the Earth. That first representation was very basic, because it was created as a flat expanse, with a river running along it separating the land areas into two sections.
Centuries later, it was the Greeks who began to theorize about the possibility that the surface of the Earth was round and, with that in mind, they began to draw some planispheres in which they located the extension of water that is now known as the Mediterranean Sea, as the center of the Earth, surrounded by the known extensions of land.
In the Middle Ages, the existence of world maps was absolutely decisive for the planning and creation of new navigation routes, not only to extend trade, but also to annex the new territories discovered throughout the process of European conquest and colonization of the new American territories.
To this day, they are still used planispheres, particularly in classrooms, to impart primary knowledge in relation to Earth Dimensions, but they have ceased to be used in other areas, because they have become ineffective, if what is wanted is to teach in a real way the extensions and proportions of the different countries and continents.
Images in the planispheres
world maps or planispheres have changed for the better over time, not only because they have been able to annex the new extensions of territories, but also the newly created forms of graphic representation have been incorporated, which expose in a more attached way the reality of the land surface.
Mercator World Map
The Mercator world map or Mercator projection was a fundamental instrument in the XNUMXth century to be able to refer to the location of countries and trade routes, but it must be understood that, due to the limitations of that time, it was very inaccurate. .
However, he became planisphere best known and used on the planet. It was created by Gerardus Mercator in the year 1569 and although it turned out to be a very useful instrument for navigators in the XNUMXth, XNUMXth and XNUMXth centuries, because it showed the Seas and oceans and the coasts of the continents. Today it is considered unreliable, because it shows the areas near the poles with measurements and dimensions that are exaggeratedly higher than they really are.
Continuing with the metric error, another problem that could be observed in the Mercator World Map is that in the areas near the equator, the land areas were mapped with very small measurements, which also have nothing to do with their real measurements.
Fuller's World Map
It receives the name of Fuller's Projection or Dymaxion, and it is a world map that was drawn by the American inventor Buckminster Fuller and that was patented in 1946. It draws the earth's surface in the form of a polyhedron that, when it is extended as a flat surface, results in a planisphere which has less distortion than the planisphere of Mercator, turning out to be much more precise.
However, it can be seen that, unlike the planisphere of Mercator, the Fuller Projection does not establish hierarchies in relation to the north or south of the planet, which is represented in the Mercator Projection, due, according to the researchers, to cultural issues.
Narukawa World Map
In the year of 1999, a Japanese designer and architect named Hajime Narukawa acquired world cartographic fame and renown, by creating what, until now, has been cataloged as the most precise profile of the Earth's surface.
His world map, baptized with the name of AuthaGraph, was created based on the origami technique. He achieved it from the division of the terrestrial globe into 96 triangles, building with them a tetrahedron, which is basically a four-sided polyhedron. So when the figure is separated, the figure of a rectangle can be obtained, with which the true proportions of the Earth can be reproduced.
Although the benefit of this world map is beyond doubt, in order to understand the way in which the Earth's surface is distributed, in a more realistic way, this planisphere it is not available to the public, because it is the property of the project catalog of the Narukawa design company, domiciled in Japan.
Elements of a planisphere
For a planisphere or world map can be of practical use, these elements are needed:
Title
It should be explained in the title of the planisphere what is shown on the map. For example, if it represents a political-territorial division, a river or ecosystem map, among others.
Geographical coordinates
Geographic coordinates are essential, because they are the references to find a location on the Earth's surface. The coordinates are integrated by:
- Latitude: measures distances in relation to parallels, which are imaginary lines that have their base at the equator.
- Length: Measures distances relative to meridians, which are imaginary lines from pole to pole.
- Altitude: the number of meters at which a territory is above sea level.
Cardinal points
With a planisphere it is customary to mark the cardinal points with a compass rose. The latter is a universal symbol that identifies east, west, north and south. This way you can easily understand the orientation of the map and the territories that are shown there.
Scale
It is a relationship between the measurement used on a plan or map and its actual proportion. It can be of two types:
Numerical scale
It is made up of two figures: the first, located on the left, is the unit of measurement used on the map. On the right, it shows the actual measurement. So, 1:100.000 means that each centimeter on the map is equivalent to one hundred thousand centimeters in the real area.
Graphic scale
This scale is used in planispheres for school use, because it is easy to explain and understand. You just need to take a ruler and measure the scale of the map. With the measurement taken, a rule of three is made.
For example, if the graphic scale says that 4 centimeters corresponds to a hundred thousand kilometers, a distance of 8 cm on the map corresponds to 200.000 kilometers in the real area.
Legend
All planisphere makes use of various symbols to represent elements: country capitals, airports, rivers, mountains, among others. Therefore, the legend is essential, because it explains the meaning of each symbol to make it easy to understand.