Serini's diary, some fridge logic

[Fyraltari]

There's also very little incentive to properly map out a desert. After all it's vast expanses of nothingness. Get the roads and places where you can find water right, the rest isn't nearly as important.

[Dr.Zero]

The only part you might be missing is that in actual history this step:



didn't happen until 1761, and that was after centuries of effort by the world's best and brightest and significant investments of resources from the world's naval powers.

I suppose that there is something about a 24h (or better a 23:59:58, to take in account the time needed to turn it) hourglass that I can't grasp, because it seems a decent solution, albeit you need a person ready to turn it as soon as the sands drops completely.
Even with an additional error of 2 secs every time added always in the same direction (which seems kind of a stretch) it needs a full month before accumulating one minute of error.

[Keltest]

I feel like people describing the mapmaking challenges that the western continent might face are neglecting to account for the fact that people can fly, teleport, and otherwise use magic. Heck, "find the path" is a 6th level cleric spell, so its not at all out of the question that Soon would be able to access it if he so desired.

[Dion]

Even with an additional error of 2 secs every time added always in the same direction (which seems kind of a stretch) it needs a full month before accumulating one minute of error.

Every two seconds of time translates to a half mile difference on the ground,

Those differences start to add up fast when you’re looking for something invisible.

[KorvinStarmast]

Is it really that complicated to measure?

I'll refer you to the book by Dava Sobel that was in my post.
It is an excellent read, and not a very long book.

[Bacon Elemental]

Serini probbably wrote the real co-ordinates of Girard's Gate in her coded diary because it's hard to remember where in a vast blasted desert in the middle of a war-torn continent you left the darn thing.


Meanwhile there's less need for her to go into depth to herself about how she's rigged her own Gate

[Goblin_Priest]

Surprisingly, getting an accurate clock isn’t hard. The whole universe is a clock. The moon is sweeping through the sky in a predictable way; the moons of Jupiter are ticking out their orbits more precisely than any mechanical clock we’ll ever be able to build.

But... the equipment, calculations, tables and procedures nescessary to let anyone do it (and not just dedicated astronomers in dedicated observatories) really only became widespread around 1800.

And I know it seems impossible today, when you can hire a surveyor to come out and position your fence to six decimal places, and even our watches will often tell us where we are within a few feet, but these measurements were not precise by modern standards!

In 1800, being off by one degree was pretty good; you’d have to spend a month of careful and repeated operations to improve much on that. But each degree is 69 miles!

So... no. Unless there’s either magic involved (or GPS) finding an invisible landmark in a featureless desert by its coordinates doesn’t make sense to me.

This is a poor answer. The problem is accurately measuring fractions. Measuring exactly how many days have passed is irrelevant to the issue at hand, measuring precisely the differences in time between specific events (noon, or sunset, or sunrise, for example) is what matters. If all you've got are tools to measure the time at your current location (such as anything based on the sun), then you lack any means to obtain the time it is currently in /another location/, the comparison with which is necessary to establish distance in terms of longitude.

I've studied in geography, with many classes relating to GIS and arpentry. These guys have been doing their job, with pretty fair accuracy, since way before the GPS. Never meant to say any random schmuk could do it. But an initiate with the proper training and a few basic tools? That's another issue. See: Eratosthenes.

The only part you might be missing is that in actual history this step:



didn't happen until 1761, and that was after centuries of effort by the world's best and brightest and significant investments of resources from the world's naval powers.

This is a far more satisfying answer, which I find quite plausible.

That said, I would add a nuance that the ability to reliably tell longitude on the fly, and for an extended period of time, would require more needed for naval travel than mapping, which, I'd expect, could do a fair enough job with much cruder tools.

After all, we do see maps being made since way before. The Cantino Planisphere dates from 1502, and it's pretty accurate.

It also all brings into question just how big the thing we want to map is. Also, how much divergence there is between the true north and the magnetic north in the OotS-verse. And if their planet is even a sphere at all. I think we've seen it as a sphere, but I'm not really sure we have. I know my own campaign setting is set on a flat world with a great ice barrier. Others are as well.

There's also very little incentive to properly map out a desert. After all it's vast expanses of nothingness. Get the roads and places where you can find water right, the rest isn't nearly as important.

If the desert is large, sparsely populated, and of little interest to the educated urban elites, than that would greatly explain why it's poorly mapped. More than technical difficulties.

I suppose that there is something about a 24h (or better a 23:59:58, to take in account the time needed to turn it) hourglass that I can't grasp, because it seems a decent solution, albeit you need a person ready to turn it as soon as the sands drops completely.
Even with an additional error of 2 secs every time added always in the same direction (which seems kind of a stretch) it needs a full month before accumulating one minute of error.

That brings the same issue as my first comment. It's not about measuring a precise 24h period, it's about measuring the difference with a precise 24h period.

[Dion]

If all you've got are tools to measure the time at your current location (such as anything based on the sun),

Agreed! Fortunately there are a lot of objects in the sky that aren’t the sun, and we can determine the time based on those objects instead.

Keep in mind that mechanical clocks are helpful as ways to determine your longitude quickly, and they’re helpful when viewing conditions aren’t ideal. But we’ve been doing longitude calculations for literally 2000 years before the invention of a reliable clock.

But even after the invention of accurate clocks, dedicated surveying crews who were charged with accuracy still calibrated their clocks to astronomical observations.

And according to Wikipedia, stellar time today is still based on astronomical observations, not on clocks (stellar time being based on the angle of some far off quasars observed with radio telescopes or whatever)

[brian 333]

While the Polynesians have a more complex system, the European version was essentially to aim for the lattitude of your goal then sail on it until you hit land. Once currents had been mapped the regular routes could be refined to make use of them, but otherwise, longitude remained an educated guess until a British guy invented the escapement thingy that makes watches tick. And then the Royal Navy screwed him out of the reward they promised for inventing a reliable method of finding longitude at sea.

[skim172]

How were those calculations done historically? All I've heard of is simultaneous observations of eclipses (obviously inconvenient unless we are planning our navigational fixes months/years in advance). What other astronomical events would work that don't require telescopes (which weren't invented until the 1600s)?

You're on the right track with "astronomical" - the answer is "celestial navigation". Eclipses may be rare, but there's a sun in the sky every day, as well as the moon, and the stars, which move in trackable and predictable patterns. Historically, navigators had excellent understanding of the celestial bodies, as their lives depended on it. You'd be amazed at how advanced even ancient navigators were and how much they had managed to extrapolate about the movement of the Earth and heavens without advanced scientific tools.


Incidentally, this is why the old myth about "everyone believed the world was flat until brave Christopher Columbus proved it was round" is complete nonsense. Sailors knew the world was round - they relied on that to be able to accurately navigate the ocean using the sun and stars. Maybe common land-bound peasants might not know, but anyone who sailed the seas and anyone who was educated knew the Earth was a globe.

In fact, Eratosthenes, a Greek scholar all the way back in 2nd century BC, calculated the circumference of the Earth and the tilt of the Earth's axis, using nothing but survey data and solar measurements. And his estimate was really accurate - off by just about 1 or 2% from the real figure. This was 200 years before Christ. Over the following millenia, our understanding of math and science and the movement of the heavens would grow, building upon that ancient knowledge.

And then 1,700 years after Eratosthenes died, Columbus came along and decided that he - and all the science and math confirming his calculations - was wrong. Not just a tiny bit wrong - amazingly, hugely wrong. Columbus' bold, grand, paradigm-shifting idea wasn't that you could reach Asia by sailing west around the globe. Everyone knew that was theoretically possible, but everyone also knew that with the shipbuilding and sailing technology of the day, any expedition would run out of water and food long before they reached Asia (and then presumably die in unpleasant ways). There was a technological and practical limit to how far their ships could travel in open seas, and Asia lay well beyond that limit.

But Columbus said NO. That wasn't true at all. HIS bold idea was that the world was way smaller than you think, and a man can definitely reach Asia by sailing west without losing their mind and eating the crew. And I ... I will be that man. And so, after several unsuccessful attempts at raising funding from less credulous audiences, Columbus delivered his 15th-century TED talk to the court of Ferdinand and Isabella of Spain - and the rest is history.

Of course, Columbus was actually incredibly wrong about his estimations - by the time his ships washed up what's now Haiti, his crew was already starving and on the verge of mutiny. And modern-day science has confirmed that Haiti is not, in fact, in Asia.

As for how wrong - in Spain, Columbus boldly declared that the distance from the Canary Islands (off the coast of Morocco) to the coast of Japan was no less than 2,400 nautical miles. For a comparison, this is roughly the distance from Miami to Vancouver. The actual distance from the Canary Islands to Japan going westwards is about 10,000 nautical miles. He was misled not only by his very incorrect estimations of the size of the planet, but also by some mistranslations and very optimistic readings of maps and other explorers' notes. In fact, it is actually significantly shorter to go eastward around the globe from the Canary Islands to Japan - about 6,700 nautical miles.

Sometimes, it's better to be lucky than good.

[Dion]

You're on the right track with "astronomical"

Wow, that’s an excellent post. Thank you.

[Onkeldata]

..awesome post...

[Insert honorific of your choice], that was really an education. I will not take it's contents as given, but the very idea that Columbus dared an expedition that was considered a fools errand by people with better understanding of earths dimension (and, it turns out, unsufficient knowledge on it's geography) just because he was in error, well, if it is not the truth it is well told anyway! I shall need to read it up.

He's was bit Elan like then, believing in the good outcome of a very heroic but stupid decision, or am I the only one getting this vibe out of it?

On the strip:
So, Checkovs Serini appeared at least, at least some of her. And I find myself angry of her lying to and beating the paladins. I am very disappointed in me. I took lengths to annoy every paladin or monk warrior that I encountered in my roleplaying days (even played one myself, and was constantly amused by my corset of behaviour rules), and now I take emotionally their side? The giant has made me root for paladins. He IS a awesome storyteller.

[Grey_Wolf_c]

Maybe common land-bound peasants might not know, but anyone who sailed the seas and anyone who was educated knew the Earth was a globe.

To misquote Pratchett, most people didn't care what shape the Earth was as long as it contained, somewhere, their next meal. But to those that were in a position to know because they were not subsistence farmers, yes, the number of proofs that the Earth is round are multitude. The most obvious being that the Earth's shadow on the moon during eclipses is round. But also: people with views to the sea and decent eyesight can just make out the flag of an incoming ship at the top of the mast before they see the hull. And if you've travelled minimally, you can see that stars are different at different latitudes.

In fact, Eratosthenes, a Greek scholar all the way back in 2nd century BC, calculated the circumference of the Earth and the tilt of the Earth's axis, using nothing but survey data and solar measurements. And his estimate was really accurate - off by just about 1 or 2% from the real figure.

Nitpick: we aren't actually sure of this, because he measured it in stadia... and we aren't sure how far that was to the Greeks (or rather, we know it depended on the greek Foot measure, which could vary by location). There is a lot of circular references when tracking down the conversion value, and the one that makes Eratosthenes work is actually derived backwards from his own measurements, re-measured in modern times.

He wasn't far off (nothing close to Columbus' hubris), but it is likely the error is actually larger than 2%.

[Insert honorific of your choice], that was really an education. I will not take it's contents as given, but the very idea that Columbus dared an expedition that was considered a fools errand by people with better understanding of earths dimension (and, it turns out, unsufficient knowledge on it's geography) just because he was in error, well, if it is not the truth it is well told anyway! I shall need to read it up.

Oh, no, it is absolutely true. It is the reason why the Portuguese king sent him packing when he pitched the idea to him. Heck, if Castille hadn't had a surplus of able bodied men, having just completed a major war, it is likely they wouldn't have bit either.

Grey Wolf

[hroþila]

Since Columbus rejected the scientific consensus of his time to pick the theory that suited his own agenda because he knew better than everyone else, ironically that might suggest he'd be a flat earther now.

[Onkeldata]

Since Columbus rejected the scientific consensus of his time to pick the theory that suited his own agenda because he knew better than everyone else, ironically that might suggest he'd be a flat earther now.

More like a *small* earther. Hey, let's take this as an initiative to found our own conspiration! Let's call it "order of the small world"

I mean, everybody keeps telling us, it is a small world, right? We keep seeing known persons at the unlikeliest places, right? Astronauts keep calling it a marble, Armstrong said, a pea. THIS IS THE PROOF! WE BEEN LIED TO! SANON WILL... (collapsing while frothing and searching for my horned pelt hat)

[Fyraltari]

Oh, are we crapping on Colombus? That man did not deserve his luck and it infuriates me. He died believing that the Caribpbean was Japan. Columbia and Colombia should change their names.

In fact, Eratosthenes, a Greek scholar all the way back in 2nd century BC, calculated the circumference of the Earth and the tilt of the Earth's axis, using nothing but survey data and solar measurements. And his estimate was really accurate - off by just about 1 or 2% from the real figure. This was 200 years before Christ. Over the following millenia, our understanding of math and science and the movement of the heavens would grow, building upon that ancient knowledge.

The story I know (which may sadly not be true) was that Erathostene used in his calculations the distance between Alexandria and some other city which was measured by counting the steps a camel took. Apparently measuring distance by watching a camel was a real job back then and that is marvelous to me.

[skim172]

Nitpick: we aren't actually sure of this, because he measured it in stadia... and we aren't sure how far that was to the Greeks (or rather, we know it depended on the greek Foot measure, which could vary by location). There is a lot of circular references when tracking down the conversion value, and the one that makes Eratosthenes work is actually derived backwards from his own measurements, re-measured in modern times.

He wasn't far off (nothing close to Columbus' hubris), but it is likely the error is actually larger than 2%

Yes, very true. However, on the flip side, because we don't know exactly what the length of stadia Eratosthenes was, there is a non-zero possibility that Eratosthenes was absolutely spot-on correct, down to the micron.

To misquote Pratchett, most people didn't care what shape the Earth was as long as it contained, somewhere, their next meal.

*conspiratorial whisper* The Turtle moves.

[Grey_Wolf_c]

Oh, are we crapping on Colombus? That man did not deserve his luck and it infuriates me. He died believing that the Caribpbean was Japan.

Maybe. Maybe not. On top of all the other terrible crimes he was guilty of, he was also a known liar. On his first trip, he kept two log books, one public one where he intentionally lied about the distance they travelled each day, and a private one with the real distance. So it is possible he knew full well that he was full of crap (there has been suggestions that he might have known about the Americas from tales about the viking colonies; I'm not sure how much hard evidence there is for this though).

GW

[KorvinStarmast]

More like a *small* earther. Hey, let's take this as an initiative to found our own conspiration! Let's call it "order of the small world"

I mean, everybody keeps telling us, it is a small world, right?

I knew that when I was about five years old. At some place run by Walt Disney. There's even a theme song for that group.

So it is possible he knew full well that he was full of crap (there has been suggestions that he might have known about the Americas from tales about the viking colonies; I'm not sure how much hard evidence there is for this though).

There are some authors, Mark Kurlansky is one, who think that Basque cod fishermen had already discovered the grand banks but kept it a trade secret, and that Columbus was in possession of a stolen or copied log book from one such ship. Not sure how strong the evidence is for that, but it's plausible, and it would fit into Cristobol Colon's penchant for presenting whatever story he thought he could get away with telling.