The Trade-offs in a Flat Map
Written by Studio AM.
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A globe represents Earth’s rounded shape, but a globe is hard to carry and hard to print in a book. So mapmakers flatten the round Earth onto a flat sheet. The trouble is that a sphere cannot be flattened without stretching some parts of it. A flat map must distort some properties. Mapmakers choose which properties to preserve for a particular purpose.
One famous world map, the Mercator projection, preserves local angles and makes a route with a constant compass bearing appear as a straight line. This made it useful for sailors steering a course. But it pays for this by stretching areas near the top and bottom of the map. Lands close to the poles look far larger than they really are. On such a map, Greenland can appear as big as Africa, though Africa is many times its size.
This does not make the map useless; it makes it a tool with a known bias. Another projection may preserve area or distances along selected routes while changing other properties. The wise reader asks not 'Is this map right?' but 'What does this map get right, and what has it traded away?'
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Questions
Choose an answer. The explanation appears after you answer.
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Question 1 of 4
The passage mainly argues
The answer is A: that every flat map must distort the round Earth, trading one accuracy for another
The passage argues that flattening a sphere forces distortion, so each map trades one kind of accuracy for another.
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Question 2 of 4
What useful feature of the Mercator projection does the passage describe?
The answer is A: A route with a constant compass bearing appears as a straight line.
Mercator preserves local angles and shows constant-bearing routes as straight lines; it does not preserve all large shapes or distances.
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Question 3 of 4
Why does the passage say a wise reader asks what a map 'traded away'?
The answer is C: Each flat map keeps one kind of accuracy by losing another
Since a flat map must distort something, no map is simply right; each keeps one accuracy by giving up another.
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Question 4 of 4
In this passage, to 'distort' shapes means to
The answer is C: show them in a false, stretched form
To distort is to alter how a property such as size or shape is represented. Here, high-latitude areas are enlarged.
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