These maps present two totally different approaches to depicting Greenland. The left map is an orthographic projection, emulating a globe. The suitable map is a Mercator projection, which exaggerates the sizes of landmasses — together with Greenland — which are closest to the poles.
Alyson Harm/NPR
conceal caption
toggle caption
Alyson Harm/NPR
President Trump is once more floating the thought 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 want Greenland, completely,” Trump stated on Sunday. “We want it for protection.”
If all this discuss makes you need to take a look at Greenland on a map, you may discover its measurement. Greenland is the world’s largest island, overlaying greater than 836,000 sq. miles.
However is Greenland actually as giant as it’d seem on a map? Seems, it is determined by the map.
Although globes provide a reasonably correct image of the world’s geography, issues get lots trickier once you attempt to depict a sphere on a two-dimensional floor. The styles and sizes of land plenty can get distorted, and distances and instructions threat turning into wonky. There are various totally different forms of world maps, and each has its strengths and weaknesses.
Some of the widespread map sorts is known as 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 resembling 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 strains.
This allowed sailors to plot a course between any two factors utilizing a straight line, however it 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, regardless that Africa is about 14 instances bigger.
“Mathematically [the parallels and meridians] get pulled aside, pulled in numerous quantities and magnitudes from the equator in direction of the poles, so you find yourself with this kind of exaggerated impact, if you’ll, within the higher latitudes the place landmasses look enormous,” 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 alternate options that provide a extra correct view of relative land measurement. The Robinson projection, which tries to raised steadiness the dimensions and shapes of land plenty, sought to resolve the “Greenland downside.” And final 12 months, the African Union threw its assist 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 choose at a given time actually is determined by what you are utilizing the map for, in accordance with Kessler.
“Is it going for use to measure distances or instructions? Angles? Areas? Present distributions of thematic knowledge, you understand, inhabitants?” he stated. “There’s a whole lot of projections that can be utilized, and the truth that we deal with only a very slim subset is I believe one other downside that must be addressed.”
