What is a planisphere?
Planisphere
What is a planisphere?
Planisphere is a representation of the earth's surface in the form of a map. Hence, it is also known as mapamundi or mapa mundi .
Planisphere is a word composed of two terms of Latin origin: planus (plane) and sphaera (sphere), which refers to the flat representation of the Earth or the celestial vault, since it is made on paper or a flat surface.
Evidence suggests that it was the Babylonians in about 2500 BC who were the first to map what they believed to be Earth at the time: a flat surface with a river that divided the territory into two parts.
Centuries later, the Greeks began to raise the possibility that the earth's surface was spherical and created planispheres in which they placed what we now know as the Mediterranean Sea as the center of the world.
In the Middle Ages, world maps were key to creating navigation routes and incorporating the new territories discovered during the process of European conquest and colonization. Today, although planispheres are still used (especially in schools), they have been shown to be ineffective in showing realistically the proportions of different countries and continents.
Planispheres images
The planispheres or world map have evolved over time, not only incorporating new territories, but also new models of graphic representation that show the earth's surface in a more realistic way.
Mercator World Map
The Mercator World Map or Mercator Projection was an essential instrument in the 16th century, but it is not very precise.
This is perhaps the best known and most used planisphere in the world. It was created by Gerardus Mercator in 1569 and although it was very useful for navigators in the 16th, 17th and 18th centuries, it is not a reliable model, since it represents the areas near the poles with dimensions much higher than the measurements real.
On the other hand, the territories near the equatorial line are mapped with very small dimensions that do not correspond to reality.
Fuller World Map
The Fuller or Dymaxion planisphere is much more accurate than Mercator's world map.
Also known as Fuller or Dymaxion projection, it is a planisphere created by the American inventor Buckminster Fuller and patented in 1946, which projects the earth's surface onto a polyhedron that, when deployed as a flat surface, results in a planisphere with a minor distortion to the Mercator map.
Furthermore, the Fuller Projection does not contemplate hierarchies with respect to north or south (as does the Mercator planisphere) since its author associated it with a cultural bias.
Narukawa World Map
In 1999, a Japanese designer and architect named Hajime Narukawa became famous in the cartography world for creating what, to date, is the most accurate representation of the earth's surface .
His map, called AuthaGraph, was created using the origami technique by dividing a terrestrial sphere into 96 triangles with which he built a tetrahedron (four-sided polyhedron). When unfolding the figure, a rectangle is obtained that respects the original proportions of the Earth.
Despite its usefulness to understand the distribution of the earth's surface in a more realistic way, this planisphere is not publicly accessible, since it is part of the project catalog of the Narukawa design company, located in Japan.
Elements of a planisphere
For a planisphere or world map to be functional, it requires these elements:
Qualification
The planisphere must explain in a title what is shown in the cartography: if it is a political-territorial division, a river map, an ecosystem map, etc.
Geographical coordinates
Geographic coordinates are references to locate a location on the earth's surface. Is composed of:
- Latitude : measures distances based on parallels, which are imaginary lines based on the equator.
- Longitude : measures distances based on meridians, which are imaginary lines that start from the poles.
- Altitude : the number of meters that a territory is above sea level.
Cardinal points
In a planisphere the cardinal points are usually marked with a compass rose, which is a universal symbol to identify the east, west, north and south. In this way it is easier to understand the meaning of the map and the territories shown there.
Scale
A scale is a relationship between the measure 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, on the left, shows the unit of measurement used on the map. On the right, the actual measurement. Then,
1: 100,000
it means that each centimeter of the map is equivalent to one hundred thousand centimeters in reality.
Graphic scale
This type of scale is widely used in planispheres for school use because it is very easy to explain and understand. In this case, you just have to take a ruler and measure the scale of the map. With the resulting measurement a rule of three is made.
For example, if the graphic scale says that 4 centimeters corresponds to 100,000 kilometers, a distance of 8 cm on the map corresponds to 200,000 kilometers in reality.
Legend
Every planisphere uses different symbols to represent elements: capitals of countries, airports, rivers, etc. Therefore, one of the essential elements is the legend that explains what each symbol means, so that the map is easier to read.
Update date: February 28, 2021.
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