Difference between revisions of "2613: Bad Map Projection: Madagascator"
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==Explanation== | ==Explanation== | ||
− | + | This is the fifth comic in the series of [[:Category:Bad Map Projections|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 {{w|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 {{w|Mahé, Seychelles|Mahé}}. The map projection is technically a {{w|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 {{w|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 {{w|Mercator_projection#Criticism|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 {{w|antipodes|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=== | |
− | + | {| class="wikitable sortable" | |
− | + | ! Landmass | |
− | + | ! Status | |
− | + | ! data-sort-type="number"|Actual Area<ref name="act">Major contiguous land areas that should exclude all islands, ''especially'' major ones, '''''especially''''' especially those listed separately</ref><br />(Millions of Km²) | |
− | + | ! data-sort-type="number"|Proportion<br />Land Area | |
− | + | ! data-sort-type="number"|Proportion<br />Image Area<ref name="pri">Of only these listed areas listed</ref> | |
− | + | ! data-sort-type="number"|Distortion<ref name="dis">NB. Difference between percentages, rather than percentage difference</ref> | |
− | + | |- | |
− | + | | Africa<ref name="suez">Edge at Suez Canal</ref> || data-sort-value="C2"|Continent<br /><small>2nd largest</small> || 29.7 || 19.95% || 35% || +15.1% | |
− | + | |- | |
− | + | | Eurasia<ref name="suez" /> || data-sort-value="C1"|Continent<br /><small>Largest</small> || 53.4 || 35.83% || 30% || -5.83% | |
− | + | |- | |
− | + | | North America<ref name="pan">Edge at Panama Canal</ref> || data-sort-value="C3"|Continent<br /><small>3rd largest</small> || 19.3 || 12.96% || 15% || +2.04% | |
− | + | |- | |
− | + | | South America<ref name="pan" /> || data-sort-value="C4"|Continent<br /><small>4th largest</small> || 17.8 || 11.96% || 7.8% || -4.16% | |
− | + | |- | |
− | + | | Antarctica<ref name="ice">Significant ice-sheets may complicate mapped/actual 'land' areas</ref> || data-sort-value="C5"|Continent<br /><small>5th largest</small> || 14.2 || 9.53% || 5.3% || -4.23% | |
− | + | |- | |
− | + | | Madagascar || data-sort-value="I04"|Island<br /><small>4th largest</small> || 0.592 || 0.40% || 2.9% || +2.50% | |
− | + | |- | |
− | + | | Australia || data-sort-value="C7"|Continent<br /><small>Smallest</small> || 7.55 || 5.07% || 2.5% || -2.57% | |
− | + | |- | |
− | + | | Greenland<ref name="ice" /> || data-sort-value="I01"|Island<br /><small>Largest</small> || 2.17 || 1.45% || 0.87% || -0.58% | |
− | + | |- | |
− | + | | Borneo || data-sort-value="I03"|Island<br /><small>3rd largest</small> || 0.749 || 0.50% || 0.37% || -0.13% | |
− | + | |- | |
− | + | | New Guinea || data-sort-value="I02"|Island<br /><small>2nd largest</small> || 0.786 || 0.53% || 0.32% || -0.21% | |
− | + | |- | |
− | + | | Japan<ref name="hon">Honshu only</ref> || data-sort-value="I07"|Island<br /><small>7th largest</small> || 0.228 || 0.15% || 0.10% || -0.05% | |
− | + | |- | |
− | + | | Mainland Britain || data-sort-value="I09"|Island<br /><small>9th largest</small> || 0.209 || 0.14% || 0.10% || -0.04% | |
− | + | |- | |
− | + | | Island of Ireland || data-sort-value="I20"|Island<br /><small>20th largest</small> || 0.082 || 0.05% || 0.03% || -0.02% | |
− | + | |} | |
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<references/> | <references/> |
Revision as of 19:22, 8 May 2022
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[1] (Millions of Km²) |
Proportion Land Area |
Proportion Image Area[2] |
Distortion[3] |
---|---|---|---|---|---|
Africa[4] | Continent 2nd largest |
29.7 | 19.95% | 35% | +15.1% |
Eurasia[4] | Continent Largest |
53.4 | 35.83% | 30% | -5.83% |
North America[5] | Continent 3rd largest |
19.3 | 12.96% | 15% | +2.04% |
South America[5] | Continent 4th largest |
17.8 | 11.96% | 7.8% | -4.16% |
Antarctica[6] | 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[6] | 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[7] | 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% |
- ↑ Major contiguous land areas that should exclude all islands, especially major ones, especially especially those listed separately
- ↑ Of only these listed areas listed
- ↑ NB. Difference between percentages, rather than percentage difference
- ↑ 4.0 4.1 Edge at Suez Canal
- ↑ 5.0 5.1 Edge at Panama Canal
- ↑ 6.0 6.1 Significant ice-sheets may complicate mapped/actual 'land' areas
- ↑ Honshu only
Transcript
This transcript is incomplete. Please help editing it! Thanks. |
Bad map projection #248: Madagascator
⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣠⣶⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣷⣄⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⢀⣴⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣆⠀⠀⠀⠀⠀⠀⠀
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⠀⠀⠀⠀⠀⣸⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣧⠀⠀⠀⠀⠀
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⠀⠀⠀⠀⢸⣿⣿⣿⣿⣿⣿⣿⠛⠝⠛⠀⣿⣿⣿⡟⠉⢁⣀⣙⣿⣿⣿⣿⣿⣿⡇⠀⠀⠀⠀
⠀⠀⠀⠀⢸⡿⠿⣿⡿⠟⢛⣭⣿⣟⠄⠀⠻⣿⠟⠀⠾⣫⣴⣤⡙⠻⢿⡿⠿⠿⡇⠀⠀⠀⠀
⠀⠀⠀⠀⡌⠰⣄⡸⡇⠀⠘⣿⣾⡿⠀⠀⠀⠁⠀⠀⠀⠻⢷⠿⠃⠀⢸⡳⢎⡁⢸⠀⠀⠀⠀
⠀⠀⠀⠀⠡⡐⠋⢳⣷⠠⠀⠄⠍⠀⠀⠀⠀⣀⠀⠀⠀⠀⠐⠀⠀⠂⡜⠁⠈⢡⠊⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠘⣦⣤⣼⡄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢠⣧⣤⣾⡿⠀⠀⠀⠀⠀
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⠀⠀⠀⠀⠀⠀⠀⢹⣿⣿⣿⣷⣦⣀⠀⠀⠀⠀⠀⠀⠀⢀⣠⣶⣿⣿⣿⣿⡏⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠈⢿⡿⣿⣿⣿⣿⣿⣶⣶⣤⣤⣶⣶⣿⣿⣿⣿⡿⠻⠏⠁⠀⠀⠀⠀⠀⠀
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