The traditional world map, a familiar sight in countless classrooms and offices, is an enduring image of our planet. Yet, this portrayal, primarily based on the Mercator projection, is fundamentally flawed. Gerardus Mercator, a Flemish cartographer, introduced this projection in 1569, revolutionizing navigation. It allowed sailors to chart their courses in straight lines, a crucial advancement in maritime travel. However, this benefit came with a significant compromise in geographical accuracy.
Understanding why the map is “wrong” requires delving into the challenges of cartography. The Earth is not flat but an oblate spheroid, slightly flattened at the poles and bulging at the equator. Translating this three-dimensional shape into a two-dimensional representation is inherently problematic. Matthew Edney, a geography and cartography historian at the University of Southern Maine, emphasizes that every world map is distorted in some way. The key question is whether the projection prioritizes the correct shape or size of land masses, and different projections make different compromises.
The Mercator projection is conformal, maintaining the shapes of landmasses but at the expense of their relative sizes. It stretches the poles into lines as long as the equator, resulting in significant areal distortion. Regions near the poles, like Greenland and Alaska, appear much larger than they are, while equatorial regions like Africa and India are substantially minimized. For instance, Greenland appears almost the same size as Africa on a Mercator map, but in reality, Africa is nearly 14 times larger.
This distortion, Edney explains, arises from the projection’s attempt to render great circles (the shortest paths between two points on a sphere) as straight lines. To achieve this, the Mercator projection exponentially increases the separation of parallels as one moves toward the poles, leading to increased vertical stretching in these regions.
Given these inaccuracies, alternatives to the Mercator projection have been proposed. The Gall-Peters projection, popular in the 1970s and 1980s, is an equal-area map, but it significantly distorts the shapes of land masses. Land masses are stretched horizontally near the poles and vertically at the equator. Though it corrects size discrepancies, the distortion of shapes led Arthur Robinson, a renowned cartographer, to liken it to “long underwear hung on a line to dry.”
Another notable attempt is the Winkel Tripel projection, adopted by the National Geographic Society in 1998. Created in 1921, it’s a compromise projection, striving to minimize distortions in area, direction, and distance. While it doesn’t eliminate these distortions entirely, it reduces them more effectively than other small-scale maps. However, even this projection has its shortcomings, particularly in representing the Pacific Ocean, which appears larger than it is.
In 2021, a new approach emerged, devised by astrophysicists. This method presents Earth in two “pancake maps,” viewed either side by side or back to back. This novel representation differs significantly from traditional flat maps and might offer a more accurate depiction, although its adoption in educational and professional settings remains to be seen.
Ultimately, the choice of projection depends on the map’s intended use and the priorities of accuracy, whether in size, shape, or direction. Edney advocates for equal-area projections for educational purposes, aligning with the idea that understanding the real sizes of countries and continents is crucial. However, the decision often boils down to market preference.
In summary, the world map as we know it, predominantly based on the Mercator projection, is “wrong” in terms of size and distance accuracy. This stems from the inherent challenge of depicting a spherical object on a flat surface. While various projections attempt to address these distortions, each has its own set of compromises, making the perfect flat map of the Earth an elusive goal.