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1295 is the thirteenth not the fourteenth century— Preceding unsigned comment added by Iglonghurst ( talk • contribs) 08:13, 26 August 2006
Where does the name Portolan come from? Anybody know? Isoxyl 04:04, 26 January 2006 (UTC)
"Initially the preserve of Mediterranean fisherman's firsthand knoledge of the seas and coastlines. Whereas the Mappaemundi were cartographic representations of medieval culture these where closer to contempory maps. Initially they focused on the Mediterranean zone and were comparatively rudimentry, they soon became refined until they surpassed the maps of the learned geographers."
Someone put an unsigned comment in my talk page about substituting "raiding" for "trading." The answer I gave there reads as follows: "You are certainly aware of Francis Drake and his privateer activities. Spanish galleons carrying silver were routinely attacked in the Caribbean and Central America and that is not a Hollywood myth. And when Portugal, 1580 to 1640, was under Spanish rule, Portuguese fortresses in Brazil were frequently attacked by the Dutch. I have a book written by a scholar on the subject documenting such activity, but because it is a bit long, and I do not have much time to put into reading at such lengths, I have been postponing it. The book is not in Amazon, an English translation seems not to exist, and Portuguese booksellers say the book is no longer available for sale. You can see that here http://www.wook.pt/ficha/o-grande-livro-da-pirataria-e-do-corso/a/id/107133 If I get around to read it, I will walk Wikipedia a bit with the information gleaned."
The historical rationale is that the English and Dutch navies began with raiding, and only when the Spanish and Portuguese Armadas lost hegemony, did English and Dutch trading ports started being established. Deep Atlantic Blue ( talk) 19:29, 7 June 2010 (UTC)
A Portolan chart is picture of the day (10 June 2011), showing this text: "A portolan chart from 1492, the oldest known signed and dated chart of Portuguese origin. Cartography technologies greatly advanced during the Age of Discovery. Iberian mapmakers in particular focused on practical charts to use as navigational aids. Unlike Spanish maps which were regarded as state secrets, Portuguese ones were used by other countries, and Portuguese cartographers drew upon the skill and knowledge of other cultures as well."
Whereas this page contradicts that text: "With the advent of the Age of Discovery, they were considered State secrets in Portugal and Spain" — Preceding unsigned comment added by 76.126.215.43 ( talk) 16:36, 10 June 2011 (UTC)
several of these charts seem to have the writing 'upside down' as though the older orientation had north at the bottom of the page? have I got that right? is it mentioned anywhere ? EdwardLane ( talk) 11:33, 30 September 2011 (UTC)
I'm a specialist on early portolan charts. "One of the world's greatest and most enduring mysteries" like the Washington Post wrote May 22, 2010. On my user page I created several subpages that explain and discuss a lot of issues around portolans. Unique rare images and graphics are presented. Some published for the first time. I came from the German language tradition of portolan research. That is more focused on the scientific or engineering aspects, on mathematic and cartometric analysis. It traditionally suggests a Roman or Greek time origin. The present English language tradition is less mathematical and suggests a sole medieval origin.
My pages offer most English speakers for the first time the cartometric arguments about the portolans. Beginners should first read "What is unsolved about portolans? The Problem of the Portolan Charts". The pages are with lot of explanations and therefore not intended to be direct copied in the article space. Rather someone with interest on the subject and Wikipedia experience should decide what may be appropriate here. -- Portolanero ( talk) 16:55, 16 December 2011 (UTC)
I have reverted the new material inserted by Stan Lusby on the origin of portolan charts, based on non-main stream research, because it contains serious historical and technical mistakes. Please check the chapter by Tony Campbell on the 1st volume of the History of Cartography (1987), the excellent book by Ramón Pujades (2007), 'Les cartes Portolanes', and this article by Joaquim Alves Gaspar (2008): [1]. It is now consensual among researchers that portolan charts were developped in the begining of the 13th century, in the Medieterranean, and were constructed on the basis of magnetic directions given by the compass and distances estimated by the pilots. It is also false that later nautical charts were based on the Ptolemaic system of latitudes and longitudes: latitude charts, developped by the Portuguese near the end of the fifteenth century, were based on observed latitudes and magnetic courses. This well well documented in textual historical sources and confirmed by the quantitative analysis of the charts. Alvesgaspar ( talk) 09:53, 2 June 2013 (UTC)
I saw a presentation about the recent hypotheses that the portolan charts are definitely using the mercator projection and came here to read about it, only to find nothing. Is there truly such a consensus regarding this that it doesn't even deserve to be mentioned in the article? — Preceding unsigned comment added by 162.232.246.7 ( talk) 06:23, 8 March 2014 (UTC)
The article Rhumbline network is mainly about portolan charts, and is rendered doubly redundant by the article Rhumb line. I propose merging its content into this article. RockMagnetist( talk) 15:59, 20 October 2015 (UTC)
-- Mcapdevila ( talk) 21:34, 20 October 2015 (UTC)
1 a. The line or course followed by a ship or other vessel sailing in a fixed direction. Also: an imaginary line on the earth's surface intersecting all meridians at the same angle and used as the standard method of plotting a ship's course on a chart
RockMagnetist, the first problem here is that the term “rhumb” had no precise meaning when it came into use. It applied equally well to the windrose lines as it did to loxodromes because the term only applied “locally” and only meant whatever a sailor did in order to sail with constant bearing, with all the imprecision that that implies. Therefore “rhumb” was applicable to the straight lines on portolans when portolans were in use, as well as always applicable to straight lines on Mercator charts. For short distances portolan “rhumbs” do not meaningfully differ from Mercator rhumbs, but these days “rhumb” is synonymous with the mathematically precise “loxodrome” because it has been made synonymous retrospectively.
I do not believe “rhumbline network” is a real term (I defer to Alvesgaspar here) and therefore there shouldn’t be an article by that name. The Rhumbline network article needs a huge amount of work in any case. It may merit remaining independent precisely to explain the historical context and why the portolan network is not quite the same thing as a network of rhumbs. The article should be referenced from Rhumb line, Portolan chart, Mercator projection, World map and wherever else. The important concept it captures is the network of straight lines on maps intending to show sailing routes (without truly implying a precise path), as well as windrose networks. Those networks do not mean the same thing (mathematically) on every kind of map, but graphically they are all the same thing. Therefore the article describing them should make the history and purpose of such networks clear, but also make clear that they do not describe quite the same thing on each kind of map. Strebe ( talk) 15:25, 6 November 2015 (UTC)
@Rockscientist. I am afraid I am not seeing the point of these merger proposals. Why so eager to get rid of this article? Seems fine by itself, it can be connected from many other articles. Walrasiad ( talk) 09:05, 8 November 2015 (UTC)
@Rockscientist. excuse my imperfections I've rewritten the
Use of rhumblines as you've demanded.--
Mcapdevila (
talk)
17:48, 9 November 2015 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Portolan chart. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
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Cheers.— InternetArchiveBot ( Report bug) 06:17, 25 January 2018 (UTC)
Dear all
I have discussed this article with a group of experts on portolan charts, and the consensus is that it needs much improvement in scope and in content. I have volunteered to make improvements to the article and, to begin, I have drafted a table of contents that I copy below. Please let me know if anyone opposes this new outline and, if it is not the case, I will start editing the article next weekend.
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1295 is the thirteenth not the fourteenth century— Preceding unsigned comment added by Iglonghurst ( talk • contribs) 08:13, 26 August 2006
Where does the name Portolan come from? Anybody know? Isoxyl 04:04, 26 January 2006 (UTC)
"Initially the preserve of Mediterranean fisherman's firsthand knoledge of the seas and coastlines. Whereas the Mappaemundi were cartographic representations of medieval culture these where closer to contempory maps. Initially they focused on the Mediterranean zone and were comparatively rudimentry, they soon became refined until they surpassed the maps of the learned geographers."
Someone put an unsigned comment in my talk page about substituting "raiding" for "trading." The answer I gave there reads as follows: "You are certainly aware of Francis Drake and his privateer activities. Spanish galleons carrying silver were routinely attacked in the Caribbean and Central America and that is not a Hollywood myth. And when Portugal, 1580 to 1640, was under Spanish rule, Portuguese fortresses in Brazil were frequently attacked by the Dutch. I have a book written by a scholar on the subject documenting such activity, but because it is a bit long, and I do not have much time to put into reading at such lengths, I have been postponing it. The book is not in Amazon, an English translation seems not to exist, and Portuguese booksellers say the book is no longer available for sale. You can see that here http://www.wook.pt/ficha/o-grande-livro-da-pirataria-e-do-corso/a/id/107133 If I get around to read it, I will walk Wikipedia a bit with the information gleaned."
The historical rationale is that the English and Dutch navies began with raiding, and only when the Spanish and Portuguese Armadas lost hegemony, did English and Dutch trading ports started being established. Deep Atlantic Blue ( talk) 19:29, 7 June 2010 (UTC)
A Portolan chart is picture of the day (10 June 2011), showing this text: "A portolan chart from 1492, the oldest known signed and dated chart of Portuguese origin. Cartography technologies greatly advanced during the Age of Discovery. Iberian mapmakers in particular focused on practical charts to use as navigational aids. Unlike Spanish maps which were regarded as state secrets, Portuguese ones were used by other countries, and Portuguese cartographers drew upon the skill and knowledge of other cultures as well."
Whereas this page contradicts that text: "With the advent of the Age of Discovery, they were considered State secrets in Portugal and Spain" — Preceding unsigned comment added by 76.126.215.43 ( talk) 16:36, 10 June 2011 (UTC)
several of these charts seem to have the writing 'upside down' as though the older orientation had north at the bottom of the page? have I got that right? is it mentioned anywhere ? EdwardLane ( talk) 11:33, 30 September 2011 (UTC)
I'm a specialist on early portolan charts. "One of the world's greatest and most enduring mysteries" like the Washington Post wrote May 22, 2010. On my user page I created several subpages that explain and discuss a lot of issues around portolans. Unique rare images and graphics are presented. Some published for the first time. I came from the German language tradition of portolan research. That is more focused on the scientific or engineering aspects, on mathematic and cartometric analysis. It traditionally suggests a Roman or Greek time origin. The present English language tradition is less mathematical and suggests a sole medieval origin.
My pages offer most English speakers for the first time the cartometric arguments about the portolans. Beginners should first read "What is unsolved about portolans? The Problem of the Portolan Charts". The pages are with lot of explanations and therefore not intended to be direct copied in the article space. Rather someone with interest on the subject and Wikipedia experience should decide what may be appropriate here. -- Portolanero ( talk) 16:55, 16 December 2011 (UTC)
I have reverted the new material inserted by Stan Lusby on the origin of portolan charts, based on non-main stream research, because it contains serious historical and technical mistakes. Please check the chapter by Tony Campbell on the 1st volume of the History of Cartography (1987), the excellent book by Ramón Pujades (2007), 'Les cartes Portolanes', and this article by Joaquim Alves Gaspar (2008): [1]. It is now consensual among researchers that portolan charts were developped in the begining of the 13th century, in the Medieterranean, and were constructed on the basis of magnetic directions given by the compass and distances estimated by the pilots. It is also false that later nautical charts were based on the Ptolemaic system of latitudes and longitudes: latitude charts, developped by the Portuguese near the end of the fifteenth century, were based on observed latitudes and magnetic courses. This well well documented in textual historical sources and confirmed by the quantitative analysis of the charts. Alvesgaspar ( talk) 09:53, 2 June 2013 (UTC)
I saw a presentation about the recent hypotheses that the portolan charts are definitely using the mercator projection and came here to read about it, only to find nothing. Is there truly such a consensus regarding this that it doesn't even deserve to be mentioned in the article? — Preceding unsigned comment added by 162.232.246.7 ( talk) 06:23, 8 March 2014 (UTC)
The article Rhumbline network is mainly about portolan charts, and is rendered doubly redundant by the article Rhumb line. I propose merging its content into this article. RockMagnetist( talk) 15:59, 20 October 2015 (UTC)
-- Mcapdevila ( talk) 21:34, 20 October 2015 (UTC)
1 a. The line or course followed by a ship or other vessel sailing in a fixed direction. Also: an imaginary line on the earth's surface intersecting all meridians at the same angle and used as the standard method of plotting a ship's course on a chart
RockMagnetist, the first problem here is that the term “rhumb” had no precise meaning when it came into use. It applied equally well to the windrose lines as it did to loxodromes because the term only applied “locally” and only meant whatever a sailor did in order to sail with constant bearing, with all the imprecision that that implies. Therefore “rhumb” was applicable to the straight lines on portolans when portolans were in use, as well as always applicable to straight lines on Mercator charts. For short distances portolan “rhumbs” do not meaningfully differ from Mercator rhumbs, but these days “rhumb” is synonymous with the mathematically precise “loxodrome” because it has been made synonymous retrospectively.
I do not believe “rhumbline network” is a real term (I defer to Alvesgaspar here) and therefore there shouldn’t be an article by that name. The Rhumbline network article needs a huge amount of work in any case. It may merit remaining independent precisely to explain the historical context and why the portolan network is not quite the same thing as a network of rhumbs. The article should be referenced from Rhumb line, Portolan chart, Mercator projection, World map and wherever else. The important concept it captures is the network of straight lines on maps intending to show sailing routes (without truly implying a precise path), as well as windrose networks. Those networks do not mean the same thing (mathematically) on every kind of map, but graphically they are all the same thing. Therefore the article describing them should make the history and purpose of such networks clear, but also make clear that they do not describe quite the same thing on each kind of map. Strebe ( talk) 15:25, 6 November 2015 (UTC)
@Rockscientist. I am afraid I am not seeing the point of these merger proposals. Why so eager to get rid of this article? Seems fine by itself, it can be connected from many other articles. Walrasiad ( talk) 09:05, 8 November 2015 (UTC)
@Rockscientist. excuse my imperfections I've rewritten the
Use of rhumblines as you've demanded.--
Mcapdevila (
talk)
17:48, 9 November 2015 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Portolan chart. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
An editor has reviewed this edit and fixed any errors that were found.
Cheers.— InternetArchiveBot ( Report bug) 06:17, 25 January 2018 (UTC)
Dear all
I have discussed this article with a group of experts on portolan charts, and the consensus is that it needs much improvement in scope and in content. I have volunteered to make improvements to the article and, to begin, I have drafted a table of contents that I copy below. Please let me know if anyone opposes this new outline and, if it is not the case, I will start editing the article next weekend.