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Comment by zeteo | Hacker News Reader

>have our world maps been wrong or misleading for 500 years?

No, they were just used mainly for navigation. The reason why the Mercator projection was popular for so long is that its angles correspond to compass points and you navigate by a trivial algorithm:

1. Draw a line to your destination on the map and determine its angle with the north, say 25 degrees north-east.

2. Set your course at 25 degrees north-east and keep it constant. Your will arrive to your destination by a rhumb line [1], which is only slightly less efficient than a great circle.

[1] http://en.wikipedia.org/wiki/Rhumb_line

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Oh, so what you are saying is that they have been wrong and misleading for the past 500 years?

Yeah, projections are always wrong and misleading in some ways and it’s certainly important to point that out – but the Mercator projection has certain properties that are desirable for navigation but also properties that are completely undesirable for how many maps are typically used today. All that navigational stuff? Completely irrelevant for all typical use cases nowadays. Distortions of sizes? Quite relevant for typical use cases.

Just because it’s old doesn’t mean it’s good.

a) zeteo doesn't seem to be saying it is "good". b) The statement that something is "misleading" is a tense that indicates some kind of objective truth, potentially even an intention; this objectivity is certainly the case once the word "wrong" is used: "wrong" implies a rather strong statement about the map. zateo is thereby providing the context to understand that the map has a purpose, and what that purpose is; I am not certain why your response seems to take offense at that. If you are willing to state something is "wrong" if you are using it incorrectly, then all attempts to demonstrate any form of information ever are "wrong".

>Oh, so what you are saying is that they have been wrong and misleading for the past 500 years?

Umm no. You can also mislead yourself by using a slide rule to measure lengths, but that doesn't make the slide rule wrong.

That's an argument for ship captains and airplane pilots to have Mercator projection maps.

It is not an argument for Mercator projection maps to appear as the canonical Earth map in textbooks, on classroom walls, or anywhere else where education is concerned.

That is also the explanation they gave in the video. When they say "wrong or misleading", are referring to the fact that this is not always obvious when this projection is used, so it can make people think they can actually compare areas with it.

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