Greenland, a semi-autonomous Arctic island territory of Denmark, has been the subject of recent discussions regarding its potential acquisition by the United States. President Trump cited Greenland's strategic location between North America and Russia as a defense interest, stating, "We need Greenland for defense." Greenland is recognized as the world's largest island, encompassing over 836,000 square miles.
Map Distortion and Projections
However, the visual representation of Greenland's size on two-dimensional maps often differs from its actual scale. Depicting a spherical Earth on a flat surface introduces distortions in landmass shapes, sizes, distances, and directions. Various world map projections exist, each with specific strengths and weaknesses.
The Mercator Projection
One widely used projection is the Mercator projection, developed in the 16th century by Flemish cartographer Gerardus Mercator. This projection renders the Earth's curved latitudes and longitudes as straight lines, which was beneficial for marine navigation as it allowed sailors to plot courses using straight lines. A consequence of this method is the increasing distortion of landmasses further from the equator. For example, on a Mercator map, Greenland may appear similar in size to Africa, despite Africa being approximately 14 times larger. According to Penn State geography professor Fritz Kessler, this "exaggerated effect" in upper latitudes makes landmasses appear larger than they are due to the mathematical pulling apart of parallels and meridians.
Alternative Projections
Efforts have been made to promote alternative map projections that offer more accurate relative land sizes. The Robinson projection was designed to achieve a better balance of landmass sizes and shapes, aiming to address the distortions associated with Greenland's representation. More recently, the African Union endorsed an initiative to adopt the Equal Earth map, which more accurately depicts the scale of the African continent.
Conclusion
The selection of an appropriate map projection depends on its intended purpose, such as measuring distances, directions, angles, areas, or illustrating thematic data like population distribution. Hundreds of projections are available, and the widespread use of a limited number of projections is a recognized area for discussion in cartography.