Talk:Portolan chart

message: Where does the name Portolan come from?  Anybody know? Isoxyl 04:04, 26 January 2006 (UTC)
thread_title: Etymology/Origin of Name

message: 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)
thread_title:  Raiding Or Trading 

message: 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)
thread_title:  contradictions 

message: 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)
thread_title:  Modern orientation 

message: 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)
thread_title:  My Portolan Pages 

message: 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): . 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)
thread_title:  New editions reverted 

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thread_title:  External links modified (January 2018) 

message: 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.
#Definition 
#Contents
#*rhumb lines, coasts and islands, toponyms, flags, city views...
#Production
#*data compilation, drafting, copying...
#*production centers, prominent authors / schools
#Use
#Theories about their origin
#Evolution
#*Expansion of coverage area
#*Latitude charts
#*Nautical planispheres
--Hispalois (talk) 16:38, 17 November 2018 (UTC)
thread_title:  Improvement proposal