100 words - day 11

Co-ordinate Systems

Whenever you want to draw a map you are effectively depicting a 3D object (the world) onto a 2D surface (a map). We all probably did the ‘peel an orange in one go and try and lay the skin flat in a geography class in school’. The world isn’t a perfect sphere which only complicates things further!

Essentially when we map a 2D map we are trying to flatten a 3D object into a grid which represents where things are on the Earth’s surface. Through doing this we will always have to bear in mind there will be trade offs in the process of doing this. Depending on which method you use, map projections distort the shapes, sizes and distances, it is really a matter of understanding what your map is showing and then deciding what you chose to distort.

For example there is the classic Mercator map projection which is often used to show the entire world (see below) and was used as the de facto projection for navigation when it was introduced in 1569 since it preserves direction and shape. This made it useful when many explorers where sailing off across the world, however, it massively distorts size with Greenland appearing to be the same size as the continent of Africa.

There are plenty of cool graphics out there illustrating the distortion of the size of places for example here by Neil Kaye