Portolan charts

Portolan charts are realistic and detailed nautical charts of the Mediterranean and Black Seas which appeared suddenly in Italy towards the end of the 13th century. Until now most historians have assumed that these charts are based on measurements of course and distance between ports made by mariners during trading voyages and drawn by a cartographer as if the world were flat. Apart from their evident accuracy, one of the most remarkable characteristics of these charts is their close resemblance to a modern map on the Mercator projection. This study analyses five charts using quantitative geodetic and statistical techniques; this distinguishes it from existing studies, which approach the subject mostly from a qualitative historical perspective. The results are surprising. The charts are demonstrated to be more accurate than has been assumed until now and are shown to be mosaics of five to ten sub-charts, some of which have considerable overlaps. More importantly, the geodetic analysis techniques show that the map projection can only be an intentionally applied design feature of the original charts and not an accidental by-product of the presumed cartographic drawing method, as has been believed until now. The study also shows that portolan charts cannot originate in contemporary Arabic-Islamic civilisation. The consensus view that has existed until now about the origin of portolan charts is thus demonstrated to be incorrect. Their origin must therefore lie considerably further back in time.

The authors of the well-known collection Portugaliae Monumenta Cartographica hinted at connections between two anonymous portolan charts from the beginning of the sixteenth century, namely the portolan chart at the Bibliothèque Municipale of Dijon and a fragment of a chart kept in Lisbon in the Archive at Torre do Tombo. Later, they also mentioned affinities between those two charts and the famous chart known as Kunstmann III. However, they did not pursue these observations further. The present paper proceeds from where those researchers stopped investigating and proposes a fresh look on this cartographic material by combining a traditional historical approach with modern digital techniques. First, a comparative study of the toponomy of a common area of the charts will be presented. Later, each chart will be examined with the help of cartometric methods to access their implicit geometry. The advancements on the study of correlations between these charts will be shown, thus confirming that the combination of traditional and digital methods of investigation open very promising perspectives to the study of unsolved questions in the History of Cartography.

The MEDEA-CHART database was created as a tool to assist in the study of medieval and early modern nautical charts. The database also aims to facilitate access to nautical charts for both the scientific community and all members of the public. In short, we collect dispersed information on nautical charts and compile it on a single online platform, available to anyone for free. The development process started about a year and a half ago and is ongoing. MEDEA-CHART project members have an active role in the process of defining and testing newly database features, ensuring that the system reaches the level of usability required of a research tool. As development is still in progress, new features are expected to arrive in the future. We would like to extend our gratitude to Dick Pflederer for allowing the use of his census. This resource has been invaluable in populating the database. As a developer, I have found this work particularly interesting, as I have had to collaborate with researchers and learn new tools to continue to improve the system. The challenge of developing a user-friendly and innovative tool for the study of cartography is tremendously motivating. The MEDEA-CHART database can be accessed for free at https://medea.fc.ul.pt. Ricardo Vaz

A very peculiar page for an atlas which required extensive research in many fields both historical, religious and cartographical. It raises questions about the Crown of Aragon and their surveyors in Naples as well as the elusive history of Corsica.

Gdzie zaczyna się, a gdzie kończy świat? Jak wygląda? Gdzie leży jego środek? Które „krańce” są najdalsze?
Każda kultura udziela własnych odpowiedzi na pytania o obraz świata i wytwarza jego wizerunki. Wśród rozmaitych artefaktów służących opisowi i poruszaniu się po świecie szczególne miejsce zajmuje mapa – trudny do sklasyfikowania typ obiektu przybierający różne formy i funkcje, który może jawić się jako czysto praktyczny instrument, kompendium wiedzy, bądź dzieło sztuki; oscylujący gdzieś pomiędzy porządkiem utylitarnym a poznawczym, osiągnięciem technicznym a tekstem kultury. Jedno w jej charakterystyce pozostaje pewne: jej celem jest zawsze (choć różnie rozumiane) odnalezienie się w świecie.
Mapa jest narzędziem porządkowania i poznawania, ale i rozumienia świata: wędrowiec wybiera dzięki niej właściwą drogę, ale też zaczyna dostrzegać w otaczającej go przestrzeni znaki orientacyjne i ich wzajemnie relacje. Świat bez mapy jest labiryntem.

A thorough examination of the charts in the 1511 Atlas which concludes the Atlas has been reconfigured, and is set right and the overall charts that produces from the single sheets. There are two following texts on this Atlas which in the examination and determination of the whole Atlas 10 sheets.

The main objective of the workshop is to bring together researchers interested in the history of nautical cartography. In this third meeting the scope has been enlarged to include not only the genesis and evolution of the medieval portolan chart but also nautical charts in general. The proposed themes of the workshop are: • When, where, how and why the earliest nautical charts were constructed, and how they evolved over time; • The mutual influence between medieval portolan charts and traditional maps of European and non-European origin; • How the first latitude charts were constructed following the introduction of astronomical navigation, and how they evolved over time; • The use of pre-Mercator nautical charts at sea; • The role of multidisciplinary approaches to the research on old nautical charts: cartometric methods of analysis, numerical modelling, multispectral analysis, material characterization, carbon dating, etc.; • Any other subject related to the history of nautical cartography, especially concerning pre-Mercator charts.

The accuracy of portolan charts is incomparably superior to that of their closest medieval predecessors, known as mappae mundi. It has triggered several research projects, including this one, to determine their geometric properties compared to modern maps based on surveys and map projections.

Cartometric analysis was conducted on a sample of 12 portolan charts from the late 13th to late 16th centuries. The spatial extent was limited to the Adriatic Sea basin. The selected portolan charts were treated as 'identical values', and each chart was compared to a modern map of the Adriatic Sea projected in 6 map projections, treated as 'referent values'. Geometric comparisons were based on calculations of errors (displacements) between triangulated irregular networks (TINs) superimposed over each referent map (6 referent TINs) and over each portolan chart (12 identical TINs). Superimposing TINs over maps and charts allowed not only calculations of positional errors between referent–identical point pairs, but also distance error and bearing error calculations between referent–identical line pairs. Additionally, both referent and identical TINs (representing a simplified geometry of the Adriatic Sea basin on maps and charts) were divided regionally using two criteria: a) north/central/south division, and b) coastal/cross-basin/mainland-island division.

The research results showed that mapping of the Adriatic Sea basin on portolan charts, in geometric terms, is most similar to modern maps projected using the Mercator projection. If, hypothetically, graticules were to be drawn on portolan charts, the convergence of meridians would not be shown, that is, the meridians would be drawn as straight parallel lines. Also, this analysis showed that cross-basin lines on portolan charts show relatively low and very standardized bearing error values for the entire Adriatic Sea basin, while distance errors increase incrementally in a south–north direction. This pattern of distortions is similar to that of the Mercator projection and implies that the geometry of portolan charts is, most probably, primarily loxodromic.

The research results presented here are part of the author’s broader ongoing doctoral thesis research, entitled: "The Accuracy of Depictions of the Adriatic Sea on Portolan Charts".

Keywords: portolan charts, loxodromic geometry, Adriatic Sea, cartometric analysis

The two charts are subjected to an complete analysis and comparative study to others determining their origins. The Arab Compass is a text that has just appeared and I have unashamedly just copied two sections , one on the compass and the other concerning the two charts i have analysed

ÖZ
Haritacılığın ne zaman ortaya çıktığı, çizilen ilk
harita örneklerinin ne olduğu ve hangi aşamalardan
geçildiği gibi konularla birlikte portolan haritalar da
bilim insanlarının her zaman ilgisini çekmiştir. Orta
Çağdan günümüze zamanın yıpratıcı etkileri yaygın
portolan örneklerinin bulunmasını zorlaştırsa da yeni
bulgular ışığında araştırmaların devam ettiği ve
edeceği muhakkaktır. Resimlerin ve şekillerin yer aldığı
mevcut portolanların nasıl meydana getirildiği, Akdeniz
ve bu denizden faydalanan devletler ve nihayet dünya
için bu haritaların ne kadar önemli bir gelişme olduğu
bilim insanlarınca araştırılan konulardan yalnızca
birkaçıdır. Bu çalışmada da amaçlanan budur.
Çalışmada portolan haritaların ortaya çıkışı üzerindeki
tartışmalar, kullanım farklılıkları, teknik, ekonomik ve
sosyal etkileri ortaya konmaya çalışılmış ve günümüze
olan yansımaları üzerinde durulmuştur. Bu çalışmada
konu, tarihsel ve kavramsal bir yöntem uygulanarak ele
alınmış, materyal olarak konuyla doğrudan ilgili
olmayan daha önce yapılmış bilimsel çalışmalar
incelenmiş, hedeflenen amaçlar tespit edilmiş ve ilgili
konunun kavramları üzerinde durulmuştur. Harita,
bilimsel bir meta olarak Paleolitik Zamandan beri
insanın yaşamındadır. Bu nedenle kartografya ve
haritayla ilgili tüm bilimler için haritacılık tarihi diğer bir
ifadeyle kartografik geçmiş her zaman önemli bir konu
olmuştur.
Anahtar kelimeler: Orta Çağ, kartografya, harita, seyir
haritaları, portolan.
ABSTRACT
Mapping appeared when the first map, along with
examples drawn from topics such as what are and
what stage of the transition, portolan maps also
scientists have always attracted attention. The effects
of time from the Middle Ages to the present day,
although it makes it more difficult to find examples of
common portolan, research continues in the light of
new findings, and it is certain that it will. How to
present images and shapes of the pants assembled,
and the beneficiary States from the Mediterranean
Sea, and finally maps this to the world how important a
development that is researched by scientists are just a
few of the topics. This study is intended. The debate on the emergence of portolan maps in the study, differences in usage, technical, economic and social impact focuses on the repercussions of the present and has tried to find out. The subject of this study, a method taken up by applying the historical and conceptual material have been examined in earlier scientific studies that are not as directly related to the
topic and the intended use been identified and the
relevant concepts of the subject are emphasized. Map scientific as a commodity of human life since the Paleolithic. Therefore all about the history of
cartography and map cartography for the sciences, in other words, cartographic history has been always an
important topic.

The Keere Plancius Globe Gores of 1614? have a striking similarity to the Mercator 1541 Gores and both are poorly drawn to produce a proper coherent sphere. A very short paper to enthuse a researcher to take up the challenge and solve the problems highlighted.

This text continues the study carried out in my text ChGEN/1, Genoese Portolan Charts, and illustrates the influence of two Genoese cartographers who travelled to Majorca and trained many of the superb draughtsmen whose charts we so admire for their beauty.

I started this paper for another text entirely, but was asked to read a text entitled "America's Birth Certificate" which I found to be written from a position of preconception, containing spurious measurements and it decided a set of Globe Gores was for a globe when they are patently not. Having informed the original author of the problems, and been rejected i decided I must publish my findings as so many gullible people appear to have endorsed this new text. Thus this is an essay not a full on research paper as I do not have the time at present. Go to website for good views.

A negyedik velencei-török háború során (1570–1573) az Oszmán Birodalom elfoglalta Ciprust. Noha a témával foglalkozó szakirodalomban gyakran olvashatjuk, hogy a háborút a nagyhatalmú nagyvezír, Szokollu Mehmed (1565–1579) ambiciózus riválisai ötlötték ki és győzték meg a gyengekezű és befolyásolható II. Szelimet (1566–1574), a sziget elleni támadás gondolata valójában már I. Szülejmánban (1520–1566) is felmerült. A források alapján ez irányú elképzelések legkésőbb 1563-ban biztosan voltak a Portán, bár az oszmán vezetőség akkor úgy ítélte meg, hogy Málta elfoglalása nagyobb hasznot hozhat. A Mediterráneum térségét ekkor már keresztül-kasul behajózták a kor nevezetes kalózai, akik közül a legrátermettebbek aztán tudásukat a technikailag egyre fejlődő szultáni flottában kamatoztatták. II. Bajezid szultán korától (1481–1512) a török hajóhad aktivitása megnőtt, ami a térképkészítésre is ösztönző hatással volt. De milyen információkkal rendelkeztek a 16. századi oszmán térképészek Ciprus szigetéről?
https://blog.oszk.hu/foldabrosz/ciprus-abrazolas-piri-reisz-tengereszeti-konyveben

THIS IS ANOTHER TEXT WITHOUT DIAGRAMS AS THE SYSTEM WILL NOT ACCEPT A TOTAL UPLOAD. i DISCUSS THE ATLAS IN ITS TECHNICAL CONTENT AND INDICATE WHAT HAS BEEN MISSED BY OTHER RESEARCHERS INCLUDING THE FACT THAT I BELIEVE THERE ARE TWO PAGES MISSING AND INDICATE CLEARLY WHY THAT IS SO.
www.cartographyunchained.com.charts.ChCATA/1 will provide the best view of the text and full size diagrams for study purposes, really needed.