Joaquim Alves Gaspar
Universidade de Lisboa, Centre for the History of Science and Technology, Principal Investigator of the Medea-Chart project
I am a retired Navy Captain, and a specialist in Navigation, Hydrographic Surveying and Mathematical Cartography, now a researcher at the Centre for the History of Science and Technology, University of Lisbon. From about 2006 onward I have been doing research on the geometry, construction and use of pre-Mercator nautical charts. Since June 2017, I have been leading the European Research Council project MEDEA-CHART, dedicated to the study of medieval and early modern nautical charts.
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This new edition can now be purchased at: https://www.althum.com/index.php?cid=__catalogo&prid=*12E455467666A80E06894A26A1CD9F6245299F12
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Na primeira parte deste artigo passarei brevemente em revista a génese e evolução da cartografia portuguesa de meados do século XV até à preparação da viagem de Magalhães e Elcano. Irei deter-me com algum pormenor em dois aspectos normalmente ausentes na historiografia: nas inovações introduzidas pelos portugueses na cartografia náutica e nas características geométricas das cartas daí resultantes. Estas matérias estão na base de mal-entendidos e falsas interpretações, quer pelos protagonistas do passado quer pelos historiadores do presente. Um desses mal-entendidos diz precisamente respeito à localização das Molucas, fonte do valioso cravo e razão principal da viagem de Magalhães e Elcano. Na segunda parte do artigo, irei deter-me especificamente sobre a representação das Molucas na cartografia náutica, antes e depois da viagem.
This new edition can now be purchased at: https://www.althum.com/index.php?cid=__catalogo&prid=*12E455467666A80E06894A26A1CD9F6245299F12
Na primeira parte deste artigo passarei brevemente em revista a génese e evolução da cartografia portuguesa de meados do século XV até à preparação da viagem de Magalhães e Elcano. Irei deter-me com algum pormenor em dois aspectos normalmente ausentes na historiografia: nas inovações introduzidas pelos portugueses na cartografia náutica e nas características geométricas das cartas daí resultantes. Estas matérias estão na base de mal-entendidos e falsas interpretações, quer pelos protagonistas do passado quer pelos historiadores do presente. Um desses mal-entendidos diz precisamente respeito à localização das Molucas, fonte do valioso cravo e razão principal da viagem de Magalhães e Elcano. Na segunda parte do artigo, irei deter-me especificamente sobre a representação das Molucas na cartografia náutica, antes e depois da viagem.
In this paper I will show that many directions of the pelagic routes noted in the Liber could not have been measured with a marine compass because they are not affected by magnetic declination. This implies that they must have been determined using astronomical methods, for example, by taking the direction of the Pole Star or of the rising and setting of known stars as references. If most of the pelagic directions in the Liber were in fact taken from a chart, as indicated in the document, this means that a primitive type of portolan chart, not based on compass directions, was being developed at about 1200. This conclusion is consistent with the earliest extant references to the marine compass, which indicate that its use on board was exceptional during the last decades of the twelfth century.
It is further concluded that the genesis and technical evolution of the medieval portolan chart is a much longer and complex process than previously considered by the historians, who have based their analyses on the very few extant exemplars of the end of the thirteenth century, all based on compass directions. From the time the Liber was written to the making of the oldest surviving portolan charts, there was a transitional period of several decades during which directions determined at sea started to be incorporated into nautical cartography, taking profit of the improved marine compasses.
Although Robinson’s definition is remarkably synthetic and expressive, it doesn’t tell the whole story, namely about the profound differences between these two cartographic paradigms. How those differences contributed to shape the history of maps and charts will be the subject of my presentation, which will focus on three different periods: the Middle Ages, when the first nautical charts were produced in the Mediterranean; the age of the great discoveries, when the newly discovered lands were first shown to the amazed eyes of the European nations through nautical charts; and the time of the Gerard Mercator, when the great Flemish cartographer proposed his famous projection to mariners.
I will show how the image of the world conveyed by nautical charts in each of these three periods could hardly be considered as truthful, as far as the shape and size of the lands were concerned. This was not because of the limitations of the surveying and charting methods of the time - although they had certainly a relevant influence - but owing to a critical difference regarding what should be understood by an accurate depiction of the Earth, in the eyes of geographers and navigators. In some instances these differences of opinion lead to conflict and resentment. In other occasions, they materialized into apparently unsolvable technical obstacles.
Only today can we see through the mist caused by the very subtle technical questions that the protagonists of the past couldn’t interpret correctly, and fully understand the reason for all the conflicts and misunderstandings: the intrinsically different nature of maps and charts.
Although Robinson’s definition is remarkably synthetic and expressive, it doesn’t tell the whole story, namely about the profound differences between these two cartographic paradigms. How those differences contributed to shape the history of maps and charts will be the subject of my presentation, which will focus on three different periods: the Middle Ages, when the first nautical charts were produced in the Mediterranean; the age of the great discoveries, when the newly discovered lands were first shown to the amazed eyes of the European nations through nautical charts; and the time of the Gerard Mercator, when the great Flemish cartographer proposed his famous projection to mariners.
I will show how the image of the world conveyed by nautical charts in each of these three periods could hardly be considered as truthful, as far as the shape and size of the lands were concerned. This was not because of the limitations of the surveying and charting methods of the time - although they had certainly a relevant influence - but owing to a critical difference regarding what should be understood by an accurate depiction of the Earth, in the eyes of geographers and navigators. In some instances these differences of opinion lead to conflict and resentment. In other occasions, they materialized into apparently unsolvable technical obstacles.
Only today can we see through the mist caused by the very subtle technical questions that the protagonists of the past couldn’t interpret correctly, and fully understand the reason for all the conflicts and misunderstandings: the intrinsically different nature of maps and charts.
The objective of the present paper is to situate the map of Piri Reis in the context of the European cartography of the sixteenth century from which, according to its author, the geographical information was compiled. To achieve such a goal a cartometric approach was adopted consisting in analyzing the geometry of the map and comparing the results with the typical geometries of the contemporary charts. Two specific cartometric tools were used: the interpolation of the geographical grid of meridians and parallels implicit in the representation, from which the cartographical model adopted for the different regions could be identified and a gross estimate of its accuracy could be made; and the assessment of the latitude accuracy of the map, from which finer conclusions about the cartographic standards and navigational accuracy could be drawn.
The results of this quantitative analysis, complemented with the available qualitative information, have permitted to better situate the map in the context of the contemporary cartography, to identify possible sources Piri Reis might have used in its construction and to have a sounder and more detailed idea about its navigational accuracy. Contradicting previous research, it was concluded that the Piri Reis’s map is not a latitude chart: the equator and the tropics are not represented, and the length of the degree of latitude implicit in the representation is identical to the one found in the portolan charts of the fifteenth century representing Western Europe. Furthermore the old thesis that this was the most accurate representation of the world made in the sixteenth century is not confirmed. On the contrary, if some difference can be found between this map and the Portuguese and Italian sources from which it was probably compiled, it is in the sense of a poorer detail and precision.
The objective of the present paper is to situate the map of Piri Reis in the context of the European cartography of the sixteenth century from which, according to its author, the geographical information was compiled. To achieve such a goal a cartometric approach was adopted consisting in analyzing the geometry of the map and comparing the results with the typical geometries of the contemporary charts. Two specific cartometric tools were used: the interpolation of the geographical grid of meridians and parallels implicit in the representation, from which the cartographical model adopted for the different regions could be identified and a gross estimate of its accuracy could be made; and the assessment of the latitude accuracy of the map, from which finer conclusions about the cartographic standards and navigational accuracy could be drawn.
The results of this quantitative analysis, complemented with the available qualitative information, have permitted to better situate the map in the context of the contemporary cartography, to identify possible sources Piri Reis might have used in its construction and to have a sounder and more detailed idea about its navigational accuracy. Contradicting previous research, it was concluded that the Piri Reis’s map is not a latitude chart: the equator and the tropics are not represented, and the length of the degree of latitude implicit in the representation is identical to the one found in the portolan charts of the fifteenth century representing Western Europe. Furthermore the old thesis that this was the most accurate representation of the world made in the sixteenth century is not confirmed. On the contrary, if some difference can be found between this map and the Portuguese and Italian sources from which it was probably compiled, it is in the sense of a poorer detail and precision.
Em 1519, preparava-se em Espanha a viagem de Fernão de Magalhães e um número significativo de especialistas portugueses – cosmógrafos, pilotos e cartógrafos – foi envolvido nessa preparação. Dois nomes são de realçar: o do cartógrafo Jorge Reinel que, em colaboração com seu pai Pedro, terá construído um planisfério náutico que viria a constituir o modelo da cartografia da Casa de Contratación; e o de Diogo Ribeiro, que seria nomeado alguns anos mais tarde cosmógrafo de sua majestade. Em conjunto com o cartógrafo Nuño García de Toreno, Diogo Ribeiro viria a assumir um papel de grande relevo na modernização da cartografia espanhola do Atlântico.
Nesta comunicação as inovações técnicas introduzidas na cartografia náutica da Casa de la Contratación no final do primeiro quartel do século XVI são descritas e discutidas. O estudo incide, sobretudo, sobre três cartas náuticas anónimas: o planisfério de c.1519 conhecido por Kunstmann IV (hoje perdido), atribuído a Jorge Reinel; o planisfério de 1525 usualmente conhecido por Salviatti, atribuído a Nuño García de Toreno; e o planisfério de 1525 conhecido por Castiglione, atribuído a Diogo Ribeiro. As seguintes inovações conferem a estas três cartas considerável relevância histórica: a graduação do Equador e a representação da totalidade do perímetro equatorial (Kunstmann IV); a representação do Arquipélago das Moluccas no hemisfério espanhol, segundo os termos do Tratado de Tordesilhas (Kunstmann IV); a correcção da distorção provocada pela declinação magnética na representação do Mediterrâneo e Mar Negro (Salviatti, Castiglione); a representação do Mar das Caraíbas na sua escala correcta e de acordo com as latitudes dos lugares (Salviatti, Castiglione); e a ilustração de instrumentos náuticos de observação astronómica (Castiglione).
Duas técnicas de análise cartométrica foram utilizadas neste estudo: a georreferenciação das cartas antigas, a partir da qual a malha geográfica de meridianos e paralelos que lhes está implícita pode ser interpolada e interpretada; e a quantificação dos erros de latitude, por comparação entre as latitudes dos lugares representados nas cartas, medidas nas respectivas escalas, e os valores verdadeiros.
O estudo conclui que a produção cartográfica da Casa de la Contratación sofreu um impulso considerável com a preparação e realização da viagem de Magalhães-Elcano. Este impulso foi propiciado pelas ambições imperiais da Coroa Espanhola e tornado possível pelo empenhamento de cartógrafos de origem portuguesa no processo. As três cartas analisadas são os exemplos espanhóis mais antigos de incorporação de latitudes na cartografia náutica e constituíram um modelo da Casa de la Contratación durante o século XVI.
Em 1519, preparava-se em Espanha a viagem de Fernão de Magalhães e um número significativo de especialistas portugueses – cosmógrafos, pilotos e cartógrafos – foi envolvido nessa preparação. Dois nomes são de realçar: o do cartógrafo Jorge Reinel que, em colaboração com seu pai Pedro, terá construído um planisfério náutico que viria a constituir o modelo da cartografia da Casa de Contratación; e o de Diogo Ribeiro, que seria nomeado alguns anos mais tarde cosmógrafo de sua majestade. Em conjunto com o cartógrafo Nuño García de Toreno, Diogo Ribeiro viria a assumir um papel de grande relevo na modernização da cartografia espanhola do Atlântico.
Nesta comunicação as inovações técnicas introduzidas na cartografia náutica da Casa de la Contratación no final do primeiro quartel do século XVI são descritas e discutidas. O estudo incide, sobretudo, sobre três cartas náuticas anónimas: o planisfério de c.1519 conhecido por Kunstmann IV (hoje perdido), atribuído a Jorge Reinel; o planisfério de 1525 usualmente conhecido por Salviatti, atribuído a Nuño García de Toreno; e o planisfério de 1525 conhecido por Castiglione, atribuído a Diogo Ribeiro. As seguintes inovações conferem a estas três cartas considerável relevância histórica: a graduação do Equador e a representação da totalidade do perímetro equatorial (Kunstmann IV); a representação do Arquipélago das Moluccas no hemisfério espanhol, segundo os termos do Tratado de Tordesilhas (Kunstmann IV); a correcção da distorção provocada pela declinação magnética na representação do Mediterrâneo e Mar Negro (Salviatti, Castiglione); a representação do Mar das Caraíbas na sua escala correcta e de acordo com as latitudes dos lugares (Salviatti, Castiglione); e a ilustração de instrumentos náuticos de observação astronómica (Castiglione).
Duas técnicas de análise cartométrica foram utilizadas neste estudo: a georreferenciação das cartas antigas, a partir da qual a malha geográfica de meridianos e paralelos que lhes está implícita pode ser interpolada e interpretada; e a quantificação dos erros de latitude, por comparação entre as latitudes dos lugares representados nas cartas, medidas nas respectivas escalas, e os valores verdadeiros.
O estudo conclui que a produção cartográfica da Casa de la Contratación sofreu um impulso considerável com a preparação e realização da viagem de Magalhães-Elcano. Este impulso foi propiciado pelas ambições imperiais da Coroa Espanhola e tornado possível pelo empenhamento de cartógrafos de origem portuguesa no processo. As três cartas analisadas são os exemplos espanhóis mais antigos de incorporação de latitudes na cartografia náutica e constituíram um modelo da Casa de la Contratación durante o século XVI.
This will also be the time to share the main achievements of project Medea-Chart, now coming to its end, and to discuss how its legacy may be projected into the near future.