5 ms·

Portolan Charts 'Too Accurate' to Be Medieval

93 points by r0muald 11y ago

jacobolus 11y ago
Unfortunately, the dissertation under discussion here isn’t actually available for reading. http://dspace.library.uu.nl/handle/1874/291367 http://dspace.library.uu.nl/handle/1874/291367 “Full Text: Embargo until March 01 2018” There’s been a lot of theorizing about the Portolan charts (cf. this bibliography http://www.maphistory.info/portolanref.html http://www.maphistory.info/portolanref.html). Claims that they use a Mercator projection per se seem dubious to me. See this set of presentation slides by Waldo Tobler for a fun view, which the recent analysis in the linked article purports to debunk, http://www.geog.ucsb.edu/~tobler/presentations/Portolani.pdf http://www.geog.ucsb.edu/~tobler/presentations/Portolani.pdf
lifeisstillgood 11y ago
tl;dr maps From 13th Century Europe are scarily accurate, use Mercator style projection and have no obvious antecedents The level of sophistication of science in medieval Europe may be way ahead of what we assume (have we even tried to measure it?). Cartography may well have been leap frogged by one forgotten expedition but things like the Antekythera mechanism keep pointing to unsung genius and strong civilisation that we just assume did not exist - what if we were judged not by Feynmann but by Trump in 1000 years time?
- cfcef 11y ago
  > The level of sophistication of science in medieval Europe may be way ahead of what we assume (have we even tried to measure it?). I think he's not gesturing towards medieval Europe, but Rome. There was one empire which was extremely interested in the Mediterranean, the Black Sea, and England, and was bound together by ship, put a lot of effort into improving travel and logistics and measuring distances, much of which's science & math has been lost (leading to regular surprises like the Archimedes palimpsests and the Antikythera mechanism), whose maps could have lasted 800 years or so to be rediscovered by medieval Italians.
- privong 11y ago
  > Cartography may well have been leap frogged by one forgotten expedition but things like the Antekythera mechanism keep pointing to unsung genius and strong civilisation that we just assume did not exist - what if we were judged not by Feynmann but by Trump in 1000 years time? I agree with your first point, that we seem to be missing a lot of information and that early civilizations may have been more advanced than we suspect, in some ways. But I've re-read the second part a few times and I still don't know what you're getting at (beyond trying to make an "amirite?" political comment). Being judged by "Trump" means they would think we incredibly advanced because "Trump is stupid and would think we're amazing" or that we'd be judged as stupid because "Trump is stupid and wouldn't see what we had"? Likewise being judged by "Feynman" would cause us to be viewed as stupid because he's so smart or us as smart because he'd figured out how smart we are? Your point might be more effective if you termed it more concretely, instead of trying to relate it via two figures who exist in different spheres of human endeavours.
  - diziet 11y ago
    The parent was trying refer to 'judged by the achievements of' X.
ZanyProgrammer 11y ago
I think that people constantly devalue the achievements and accomplishments of the ancients (in this case, not ancients literally, but medieval people), and feel like they need to resort to lost civilizations or geniuses in the Elysian past. Especially with the Middle Ages-no one wants to admit that they were capable of engineering or scientific achievements.
- sdegutis 11y ago
  For sure. They weren't idiots, even though they had less information than we have. I mean, they produced people like Thomas Aquinas for goodness' sake. Even though we are more technologically advanced, it started somewhere. I used to ask myself, "I wonder how the ancient Greeks and Romans would have reacted if they had been shown some of our new technology." But then it occurred to me, we're just an evolution of them; in other words, they invented those technologies... but, only after a few hundred years required to get there from where they were.
- matthewbauer 11y ago
  Human intelligence has remained approximately the same for 50,000 years. The ancient world had its geniuses at the same rate as the modern world. The main difference is whether their environments enabled them to prosper. Europe really had some issues in the post Rome era that meant that most of that talent was not appreciated and lots of knowledge was lost. It sounds like this stuff came from even earlier and had been passed down without knowledge of how they were produced.
  - cfcef 11y ago
    > Human intelligence has remained approximately the same for 50,000 years. The ancient world had its geniuses at the same rate as the modern world. No, they didn't. Human genetic intelligence may be the same (although this is doubtful because as ancient genomes slowly become available for analysis, we see ever more signs of huge numbers of frequencies changing in soft selection sweeps when we go back only a few thousand years in Europe, so 50k years...?), but the environments are not nearly the same. The ancient world was absolutely grindingly dirt-poor compared to the modern world, and the negative environmental accordingly huge. (Even things like sanitation may not have made a difference: http://www.theatlantic.com/health/archive/2016/01/ancient-roman-toilets-gross/423072/?single_page=true http://www.theatlantic.com/health/archive/2016/01/ancient-ro... ) The most comparable places to the ancient world right now would be somewhere like subsaharan Africa, where between the subsistence agriculture, parasites, poverty, and whatnot, despite the benefits of widespread literacy and vaccines, the average IQ is still quite low, somewhere around IQ 80, or at least 1 standard deviation below the West; with genius at a cutoff of IQ 140 or so, that implies a rate of geniuses much less than 1/8th the Western rate. So no, the rate isn't going to be nearly the same. I would note that it's probably not an accident that when we think of geniuses of antiquity, we tend to think of people drawn from the urban elite of the capital city of empires at their peak (eg Athens, Rome)...
simonh 11y ago
We know that astronomers and architects in the ancient and medieval world were capable of formidable feats of measurement and geometric design. The existence of the Antikythera mechanism despite no known contemporary written accounts of such mechanisms or their uses shown just how many very large holes there are in our understanding on the state of the art in ancient world science and technology in this area. Even Eratosthenes map of the Mefiteranean and Black Sea from circa 194 BC are easily recognisable and contain all the main geographic features and rough proportions. Even the map of Britain is a half decent approximation for someone in Alexandria. Navigators must have had access to all the same instruments and mathematical knowledge, and had a very considerable interest in using them effectively. The results would also have been a vital competitive advantage. As the linked article says, these charts were considered state secrets. But obviously, it must have been alien Atlantans from Mars. Or something.
- huxley 11y ago
  > The existence of the Antikythera mechanism despite no known contemporary written accounts of such mechanisms or their uses Actually there are a few written accounts of mechanisms similar to the Antikythera, probably best known are Cicero's accounts which describe two devices: one by his teacher Posidonios, which Cicero is believed to have seen (so roughly contemporaneous), and another created by Archimedes, which most likely he hadn't.
  - simonh 11y ago
    Interesting, I'd not heard that before. I'll look those up, thanks.
emmelaich 11y ago
The Mercator style projection is interesting. My rank speculation is that the originals were drawn during the Roman empire on spheres and then taken off to form the mosaic.
es0m 11y ago
Fixed link to Uni Utrecht press release: http://www.uu.nl/en/news/origin-of-medieval-sea-charts-disproven http://www.uu.nl/en/news/origin-of-medieval-sea-charts-dispr... Open access version of one of the student's recent articles: http://dspace.library.uu.nl/bitstream/handle/1874/327279/Nicolai.pdf?sequence=1 http://dspace.library.uu.nl/bitstream/handle/1874/327279/Nic... The thesis is not public as he's written a book on this: http://www.brill.com/products/book/enigma-origin-portolan-charts?page=4 http://www.brill.com/products/book/enigma-origin-portolan-ch...
- jacobolus 11y ago
  Thanks for the link. I find most of the analysis logically dubious (in particular, there’s no mention of astronomy, the author seems to me to have limited imagination about possible methods for constructing charts over the course of decades or centuries of work in a field considered an important economic advantage, and the statistical analysis begs the question more than a little bit), and the conclusion “13th century Italians weren’t sophisticated enough to do this, and I don’t know any prior group who was sophisticated enough, but it must have been the Byzantines or Ancient Greeks or something, who knows” is entirely unconvincing. Calling this paper a “proof” of anything is a rhetorical stretch. But at least we’re now dealing with something more concrete than a press release.
deleted 11y ago
[deleted]

93 points by r0muald 11y ago

Unfortunately, the dissertation under discussion here isn’t actually available for reading. http://dspace.library.uu.nl/handle/1874/291367 http://dspace.library.uu.nl/handle/1874/291367 “Full Text: Embargo until March 01 2018” There’s been a lot of theorizing about the Portolan charts (cf. this bibliography http://www.maphistory.info/portolanref.html http://www.maphistory.info/portolanref.html). Claims that they use a Mercator projection per se seem dubious to me. See this set of presentation slides by Waldo Tobler for a fun view, which the recent analysis in the linked article purports to debunk, http://www.geog.ucsb.edu/~tobler/presentations/Portolani.pdf http://www.geog.ucsb.edu/~tobler/presentations/Portolani.pdf

lifeisstillgood 11y ago

tl;dr maps From 13th Century Europe are scarily accurate, use Mercator style projection and have no obvious antecedents The level of sophistication of science in medieval Europe may be way ahead of what we assume (have we even tried to measure it?). Cartography may well have been leap frogged by one forgotten expedition but things like the Antekythera mechanism keep pointing to unsung genius and strong civilisation that we just assume did not exist - what if we were judged not by Feynmann but by Trump in 1000 years time?

cfcef 11y ago
> The level of sophistication of science in medieval Europe may be way ahead of what we assume (have we even tried to measure it?). I think he's not gesturing towards medieval Europe, but Rome. There was one empire which was extremely interested in the Mediterranean, the Black Sea, and England, and was bound together by ship, put a lot of effort into improving travel and logistics and measuring distances, much of which's science & math has been lost (leading to regular surprises like the Archimedes palimpsests and the Antikythera mechanism), whose maps could have lasted 800 years or so to be rediscovered by medieval Italians.
privong 11y ago
> Cartography may well have been leap frogged by one forgotten expedition but things like the Antekythera mechanism keep pointing to unsung genius and strong civilisation that we just assume did not exist - what if we were judged not by Feynmann but by Trump in 1000 years time? I agree with your first point, that we seem to be missing a lot of information and that early civilizations may have been more advanced than we suspect, in some ways. But I've re-read the second part a few times and I still don't know what you're getting at (beyond trying to make an "amirite?" political comment). Being judged by "Trump" means they would think we incredibly advanced because "Trump is stupid and would think we're amazing" or that we'd be judged as stupid because "Trump is stupid and wouldn't see what we had"? Likewise being judged by "Feynman" would cause us to be viewed as stupid because he's so smart or us as smart because he'd figured out how smart we are? Your point might be more effective if you termed it more concretely, instead of trying to relate it via two figures who exist in different spheres of human endeavours.
- diziet 11y ago
  The parent was trying refer to 'judged by the achievements of' X.

ZanyProgrammer 11y ago

I think that people constantly devalue the achievements and accomplishments of the ancients (in this case, not ancients literally, but medieval people), and feel like they need to resort to lost civilizations or geniuses in the Elysian past. Especially with the Middle Ages-no one wants to admit that they were capable of engineering or scientific achievements.

sdegutis 11y ago
For sure. They weren't idiots, even though they had less information than we have. I mean, they produced people like Thomas Aquinas for goodness' sake. Even though we are more technologically advanced, it started somewhere. I used to ask myself, "I wonder how the ancient Greeks and Romans would have reacted if they had been shown some of our new technology." But then it occurred to me, we're just an evolution of them; in other words, they invented those technologies... but, only after a few hundred years required to get there from where they were.
matthewbauer 11y ago
Human intelligence has remained approximately the same for 50,000 years. The ancient world had its geniuses at the same rate as the modern world. The main difference is whether their environments enabled them to prosper. Europe really had some issues in the post Rome era that meant that most of that talent was not appreciated and lots of knowledge was lost. It sounds like this stuff came from even earlier and had been passed down without knowledge of how they were produced.
- cfcef 11y ago
  > Human intelligence has remained approximately the same for 50,000 years. The ancient world had its geniuses at the same rate as the modern world. No, they didn't. Human genetic intelligence may be the same (although this is doubtful because as ancient genomes slowly become available for analysis, we see ever more signs of huge numbers of frequencies changing in soft selection sweeps when we go back only a few thousand years in Europe, so 50k years...?), but the environments are not nearly the same. The ancient world was absolutely grindingly dirt-poor compared to the modern world, and the negative environmental accordingly huge. (Even things like sanitation may not have made a difference: http://www.theatlantic.com/health/archive/2016/01/ancient-roman-toilets-gross/423072/?single_page=true http://www.theatlantic.com/health/archive/2016/01/ancient-ro... ) The most comparable places to the ancient world right now would be somewhere like subsaharan Africa, where between the subsistence agriculture, parasites, poverty, and whatnot, despite the benefits of widespread literacy and vaccines, the average IQ is still quite low, somewhere around IQ 80, or at least 1 standard deviation below the West; with genius at a cutoff of IQ 140 or so, that implies a rate of geniuses much less than 1/8th the Western rate. So no, the rate isn't going to be nearly the same. I would note that it's probably not an accident that when we think of geniuses of antiquity, we tend to think of people drawn from the urban elite of the capital city of empires at their peak (eg Athens, Rome)...

simonh 11y ago

We know that astronomers and architects in the ancient and medieval world were capable of formidable feats of measurement and geometric design. The existence of the Antikythera mechanism despite no known contemporary written accounts of such mechanisms or their uses shown just how many very large holes there are in our understanding on the state of the art in ancient world science and technology in this area. Even Eratosthenes map of the Mefiteranean and Black Sea from circa 194 BC are easily recognisable and contain all the main geographic features and rough proportions. Even the map of Britain is a half decent approximation for someone in Alexandria. Navigators must have had access to all the same instruments and mathematical knowledge, and had a very considerable interest in using them effectively. The results would also have been a vital competitive advantage. As the linked article says, these charts were considered state secrets. But obviously, it must have been alien Atlantans from Mars. Or something.

huxley 11y ago
> The existence of the Antikythera mechanism despite no known contemporary written accounts of such mechanisms or their uses Actually there are a few written accounts of mechanisms similar to the Antikythera, probably best known are Cicero's accounts which describe two devices: one by his teacher Posidonios, which Cicero is believed to have seen (so roughly contemporaneous), and another created by Archimedes, which most likely he hadn't.
- simonh 11y ago
  Interesting, I'd not heard that before. I'll look those up, thanks.

emmelaich 11y ago

The Mercator style projection is interesting. My rank speculation is that the originals were drawn during the Roman empire on spheres and then taken off to form the mosaic.

es0m 11y ago

Fixed link to Uni Utrecht press release: http://www.uu.nl/en/news/origin-of-medieval-sea-charts-disproven http://www.uu.nl/en/news/origin-of-medieval-sea-charts-dispr... Open access version of one of the student's recent articles: http://dspace.library.uu.nl/bitstream/handle/1874/327279/Nicolai.pdf?sequence=1 http://dspace.library.uu.nl/bitstream/handle/1874/327279/Nic... The thesis is not public as he's written a book on this: http://www.brill.com/products/book/enigma-origin-portolan-charts?page=4 http://www.brill.com/products/book/enigma-origin-portolan-ch...

jacobolus 11y ago
Thanks for the link. I find most of the analysis logically dubious (in particular, there’s no mention of astronomy, the author seems to me to have limited imagination about possible methods for constructing charts over the course of decades or centuries of work in a field considered an important economic advantage, and the statistical analysis begs the question more than a little bit), and the conclusion “13th century Italians weren’t sophisticated enough to do this, and I don’t know any prior group who was sophisticated enough, but it must have been the Byzantines or Ancient Greeks or something, who knows” is entirely unconvincing. Calling this paper a “proof” of anything is a rhetorical stretch. But at least we’re now dealing with something more concrete than a press release.

deleted 11y ago

[deleted]