The visual discrepancy of Greenland appearing vast, often comparable in size to Africa, is a common observation when looking at a world map. This perception is not an optical illusion but a direct result of flattening the curved, three-dimensional surface of the Earth onto a two-dimensional plane.
The map causing this visual error is the one most familiar globally, and its design prioritizes one geographic property at the expense of another. Understanding this distortion requires exploring the fundamental challenge of cartography.
The Cartographic Challenge of Mapping a Sphere
Representing a spherical object on a flat sheet is mathematically impossible if one wishes to preserve all properties perfectly. The Earth’s curved nature means that translating it onto a flat map requires stretching, compressing, or tearing the surface. Cartographers must choose which geographic properties they maintain and which they distort.
It is impossible for a single world map to simultaneously display accurate shape, true distance, correct direction, and proportional area. This dilemma forces mapmakers to create projections, which are the systematic methods used to transfer coordinates from the globe onto a plane. The choice of projection significantly impacts the visual perception of the world, especially concerning the relative sizes of landmasses.
The Mercator Projection: Distorting Area for Navigation
The map responsible for the visual exaggeration of Greenland is the Mercator projection, developed by Flemish geographer Gerardus Mercator in 1569. This map was specifically designed for maritime navigation, not general use. Its defining feature is that it preserves angles and shapes locally, making it a conformal projection.
The most valuable property for sailors is that a straight line on a Mercator map represents a line of constant true bearing, known as a rhumb line. This allows a ship to follow a single compass direction without adjusting its course, which was immensely practical for long voyages.
To preserve direction, the Mercator projection forces the lines of longitude, which converge at the poles on a globe, to be parallel and equally spaced on the map. To balance this horizontal stretching, the map must also stretch landmasses vertically away from the equator toward the poles. The farther a landmass lies from the equator, the more exaggerated its size becomes, leading to the disproportionate appearance of regions like Canada, Russia, and Greenland.
The True Scale: Comparing Greenland and Africa
The visual distortion inherent in the Mercator map is demonstrated when comparing Greenland and Africa. On this projection, Greenland often appears visually larger than Africa, leading to a misconception about global geography. In reality, the difference in size is immense, highlighting the extent of the map’s distortion.
Africa spans approximately 30.3 million square kilometers, making it the second-largest continent. Greenland has a total landmass of about 2.1 million square kilometers. These figures reveal that Africa is over 14 times larger than Greenland. This comparison underscores that the visual representation on the Mercator map is a consequence of its design as a navigational tool.
Projections That Preserve Area
To correct the misrepresentation of size caused by the Mercator projection, cartographers developed alternative maps known as equal-area projections. These maps sacrifice the preservation of shape and angle to accurately depict the relative sizes of all landmasses. They ensure that any two regions on the map are scaled in correct proportion to their actual size on the globe.
One of the most recognized equal-area maps is the Gall-Peters projection, which became widely known in the 1970s. This cylindrical projection displays the continents with their true proportional area, causing Africa to appear much larger and closer to its actual size relative to the northern continents. However, to achieve this, the Gall-Peters map distorts the shapes of the continents, making them appear elongated and stretched, particularly near the poles and the equator.
Other equal-area options, such as the Mollweide projection, use curved lines of latitude and longitude to minimize shape distortion while maintaining area accuracy. Maps like the Winkel Tripel projection are known as compromise projections, designed to offer a balance between the accurate representation of area, shape, and distance. These alternatives demonstrate that mapmaking involves a conscious choice, and the perceived size of Greenland is a consequence of choosing a map designed for navigation rather than for accurately comparing landmasses.