The fact that the Earth is a sphere made it difficult for explorers to create a decent map of any area that they explored. The further one moves from the equator, the more distortion in size there would be since the areas approaching the north and south poles represent the least circumference on the globe. The north and south poles are left off of Mercator maps since they would be ridiculously large, it would be much like trying to divide by zero. Regardless, navigators did not care about the size of the landforms since they now had a map that would allow them to plot courses on an east-west and north-south grid that was laid out in perpendicular fashion. Global Positioning Satellite (GPS) systems constantly correct the flatness of the earth as they move from point to point as if you were looking straight down on the area (as the satellites are) so the distortion is minimized. In this Mercator map of the world, notice that Greenland seems as large, if not larger than Africa, when in fact it is 1/15 This is due to the massive distortion as you move away from the equator and try to flatten a sphere into a cylinder (unrolled into a rectangle). Source.