2613: Bad Map Projection: Madagascator

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Bad Map Projection: Madagascator

Title text: The projection's north pole is in a small lake on the island of Mahé in the Seychelles, which is off the top of the map and larger than the rest of the Earth's land area combined.

Explanation

This is the fifth comic in the series of Bad Map Projections displaying Bad Map Projection #248: Madagascator. It came about 10 months after the fourth 2489: Bad Map Projection: The Greenland Special (#299).

This time, Randall used the classic Mercator projection but instead of placing the North Pole on top and the South Pole on the bottom it is oriented so that the top is the island of Mahé. The map projection is technically a Oblique Mercator projection, with an unusual choice of the cylinder's axis. Since the Mercator projection tends to visually distort areas near the top and bottom of the resulting map, this gives some areas, notably Madagascar, very unusual shapes, hence the name the Madagascator — a portmanteau of "Madagascar" and "Mercator"!

The Mercator projection became the standard projection for world maps during the 1800s, because a straight line (or rhumb line) in a Mercator map represents a constant bearing relative to true north. Historically, when navigation was performed by compass, this was a very valuable feature, since one (adjusting for the differences between true and magnetic north) could plot a constant-bearing course between two locations by simply looking at their relative direction on the map.

However, in the mid-20th century, the Mercator was criticized because it causes distortion near the north and south poles of the map, giving an inaccurate impression of relative sizes. The most commonly given example of this is the size of Greenland — although on the Mercator it appears to be larger than Africa in area, Africa in reality covers an area 14 times that of Greenland.

Randall turns this example on its head by making Madagascar, rather than Greenland, appear larger in the Madagascator than in reality. By contrast with Greenland, the world's largest non-continent island, Madagascar is only the fourth-largest island in the world, behind Greenland, New Guinea, and Borneo.

To accomplish this, instead of placing the north pole of the map at the geographic North Pole, Randall places the north pole of the map on the island of Mahé in Seychelles. As Madagascar is relatively close to Mahé (around 650 mi (1050 km) distant), placing the north pole of the Mercator projection at Mahé significantly distorts the size of Madagascar, making it appear comparable in size to Europe on the map.

But this distortion is even more pronounced when it comes to the island of Mahé itself, as Randall notes in the title text. Although Mahé, the largest island in Seychelles with an area of 60.7 square mi (157.2 square km), is minuscule even compared to Madagascar, the claim in the title text that it appears "larger than the rest of the Earth's land area combined" is an understatement.

No part of Mahé is visible in the comic, but clicking on the actual comic will open a website that displays Mercator projections with a pole in any chosen location, with the location of the one opened set to Mahé. The chosen pole is (infinitely far to) the right of the screen, while its antipode is on the left. With this, it is possible to see that the island is indeed larger than the rest of the map's land area combined. A single national park within the island rivals Africa in size, and the narrow dirt road closest to the pole appears thicker than Panama. This also reveals that the location of the map's north pole (the "small lake" mentioned by Randall) is the lake impounded by the Rochon Dam, a popular tourist location in Mahé.

Unlike previous Bad Map Projections, Morocco and Western Sahara are drawn as one unlabelled country.

Comparison of actual/mapped areas

Landmass	Status	Actual Area (Millions of Km²)	Proportion Land Area	Proportion Image Area	Distortion
Africa	Continent 2nd largest	29.7	19.95%	35%	+15.1%
Eurasia	Continent Largest	53.4	35.83%	30%	-5.83%
North America	Continent 3rd largest	19.3	12.96%	15%	+2.04%
South America	Continent 4th largest	17.8	11.96%	7.8%	-4.16%
Antarctica	Continent 5th largest	14.2	9.53%	5.3%	-4.23%
Madagascar	Island 4th largest	0.592	0.40%	2.9%	+2.50%
Australia	Continent Smallest	7.55	5.07%	2.5%	-2.57%
Greenland	Island Largest	2.17	1.45%	0.87%	-0.58%
Borneo	Island 3rd largest	0.749	0.50%	0.37%	-0.13%
New Guinea	Island 2nd largest	0.786	0.53%	0.32%	-0.21%
Japan	Island 7th largest	0.228	0.15%	0.10%	-0.05%
Mainland Britain	Island 9th largest	0.209	0.14%	0.10%	-0.04%
Island of Ireland	Island 20th largest	0.082	0.05%	0.03%	-0.02%

Transcript

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Bad map projection #248: Madagascator

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