Show HN: See what country you would hit if you went straight (1 BC → Present)

Re:Show HN: See what country you would hit if you went strai... by brgross on Wednesday August 20, 2025 @02:18PM (#44964609)

I went with great circles since that feels like the most “natural” straight line on a sphere — the path you’d walk if you just kept going forward without steering. You could define "straight" as a constant compass direction (I think it's called a "rhumb") -- that would look straight on a Mercator map but would actually require regular steering adjustments to maintain the bearing.

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Re:Show HN: See what country you would hit if you went strai... by munchler on Wednesday August 20, 2025 @02:23PM (#44964652)

That makes sense, but I think constant latitude, in particular, is a special case that people often have in mind.

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Re:Show HN: See what country you would hit if you went strai... by zamadatix on Wednesday August 20, 2025 @02:55PM (#44965021)

The other methods are about defining different meanings of what "going around" actually is while constant latitude is a special case of many such methods, e.g. great circle, not a new definition of what going that way means.

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Re:Show HN: See what country you would hit if you went strai... by munchler on Wednesday August 20, 2025 @04:09PM (#44965895)

I'm not sure what you mean, but a circle of constant latitude is definitely not a great circle (except on the equator).

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Re:Show HN: See what country you would hit if you went strai... by zamadatix on Wednesday August 20, 2025 @04:53PM (#44966338)

You're 100% right, I conflated great circle and small circle there.

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