These maps present two completely different approaches to depicting Greenland. The left map is an orthographic projection, emulating a globe. The fitting map is a Mercator projection, which exaggerates the sizes of landmasses — together with Greenland — which might be closest to the poles.
Alyson Harm/NPR
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Alyson Harm/NPR
President Trump is once more floating the concept of annexing Greenland, the semiautonomous Arctic island that could be a territory of Denmark.
Greenland’s location between North America and Russia offers it strategic worth for the U.S., which already has a army base there. “We do need Greenland, absolutely,” Trump stated on Sunday. “We need it for defense.”
If all this discuss makes you wish to take a look at Greenland on a map, you may discover its measurement. Greenland is the world’s largest island, protecting greater than 836,000 sq. miles.
However is Greenland actually as massive as it would seem on a map? Seems, it is determined by the map.
Although globes provide a fairly correct image of the world’s geography, issues get quite a bit trickier whenever you attempt to depict a sphere on a two-dimensional floor. The sizes and styles of land lots can get distorted, and distances and instructions threat changing into wonky. There are a lot of completely different varieties of world maps, and each has its strengths and weaknesses.
One of the frequent map varieties is named the Mercator projection, named for the Sixteenth-century Flemish cartographer who invented it. That is the one you might have seen in an atlas as a child, and a model of it is utilized in on-line mapping instruments similar to Google Maps.
Mercator’s map takes the Earth’s latitudes and longitudes (parallels and meridians) — which curve across the spherical globe — and makes them straight traces.
This allowed sailors to plot a course between any two factors utilizing a straight line, but it surely additionally created distortions within the map the additional you bought from the equator. For instance, Greenland seems roughly the identical measurement because the continent of Africa on a Mercator map, although Africa is about 14 occasions bigger.
“Mathematically [the parallels and meridians] get pulled apart, pulled in different amounts and magnitudes from the equator towards the poles, so you end up with this sort of exaggerated effect, if you will, in the upper latitudes where landmasses look huge,” stated Fritz Kessler, a Penn State geography professor and map projection professional.
There have been organized efforts to maneuver away from the Mercator projection and use options that provide a extra correct view of relative land measurement. The Robinson projection, which tries to raised steadiness the configurations and dimensions of land lots, sought to resolve the “Greenland problem.” And final yr, the African Union threw its help behind a push to switch Mercator with the Equal Earth map, which higher renders the continent’s scale.
However which of the quite a few map projections you decide at a given time actually is determined by what you are utilizing the map for, in accordance with Kessler.
“Is it going to be used to measure distances or directions? Angles? Areas? Show distributions of thematic data, you know, population?” he stated. “There’s hundreds of projections that can be used, and the fact that we focus on just a very narrow subset is I think another problem that should be addressed.”
