All the maps of the world are wrong!
And some are probably racist too
A map is a representation of the earth on a flat surface. Contrary to the beliefs of flat Earth conspiracy theorists, Earth is a sphere. Although it is not a perfect sphere, the assumption is not inaccurate. However, this poses map makers a problem — representing a 3-dimensional object on a 2-dimensional surface.
The easiest solution would be to cut the sphere and flatten it out. But this is not possible! Carl Fredrich Gauss’ Theorema Engregium proves that a sphere and flat surface have different Gaussian curvatures — implying that a sphere cannot be modified to a flat surface without stretching or distorting the surface.
So how do the map makers actually do this?
They do this by a process called projection. Imagine that the globe is in a hollow paper cylinder. Each point on the globe is projected on the cylinder, which is then opened up to make a flat surface. This is just one type of projection called the Mercator projection. It is the most commonly used map projection.
The Mercator projection was first presented by the Flemish geographer and cartographer Gerardus Mercator in 1569. Maps in the 16th century were mostly made for one purpose — navigation. The Mercator projection was perfect for navigation as a line made between any two points on the map makes the same angle with the vertical as the route on the surface of the earth makes with the longitudes. This means that navigators (mostly sailors) could use the map to easily find the best way to their destination.
The Mercator projection also maintained the shapes of the continents really well. The shapes of the continents as seen from the space match the shapes in the Mercator projection well.
But as mentioned earlier, a sphere cannot be accurately represented on a flat surface. In order to have the correct angles, the Mercator projection compromises on the distance — ie it stretches the distance between two points as we go away from the equator. Although the shapes are not affected a lot by this, the area is highly distorted. This is very clearly visible in the case of Greenland and Africa.
On the Mercator projection, Greenland looks almost the same size as Africa, but in reality, the land area of Africa is 14 times the land area of Greenland. Similarly, Antarctica looks way too big in the projection. In reality, it is less than half the size of Africa. Since both Greenland and Antarctica are far north and south respectively, they are stretched and Africa being right at the equator is not. To better see this phenomenon, you can solve the Mercator Puzzle.
The Mercator projection map is also accused of being racist since it particularly makes the United States and Europe much larger, showing higher prominence. Since maps are no longer used for navigation (except for Google maps which also uses the Mercator projection) there is no advantage of using a Mercator projection map.
Mercator projection is not the only kind of projection available. There are hundreds of projections which allow maps to the users to have no distortion in any of the particular properties like:
- Area
- Shape
- Direction
- Bearing
- Distance
The Gall-Peters projection map is a rectangular map that maps all areas such that they have the correct sizes relative to each other. However, it distorts the shapes quite a bit.
It is pretty clear that no map is perfect. Each has its advantages and disadvantages. Choosing which map to use purely depends on what functionality the map would serve. To understand how each different type of projection would distort the maps, imagine you make equidistant spots on a globe.
These images show how these spots would be distorted and placed in a particular projection. These give us a good understanding of the distortion in direction, shape, area, etc.
It is pretty fair to say that no map can truly portray the earth on a flat surface, and though the earth is not a perfect sphere, a globe is the best way to make a model for the earth.
