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ERATOSTHENES, HIPPARCHUS AND STRABO: Geographia. The Length of the Oikoumene measured on an aslant alignment

The geographical data which can be attributed to Eratosthenes’ is available to us through the text of Strabo’s “Geography”. Unfortunately Strabo was neither a geographer nor a mathematician, but more a social historian, preferring to write mostly about that subject. However, we can glean from the text sufficient geographical data to enable a reasonable reconstruction of Eratosthenes’ world, and confirm some of the distance measures utilised.

The size of the world, 252000 Stadia (of unconfirmed) length is analysed, and then the length of the Stadion determined from the data collated. The metrology for determining the inter-distances from place to place is examined, and conclusions drawn that will require cartographic history to be updated.

8 A4 pages and 11 full colour diagram maps

April 2010
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335 341

STRABO: DECLARATIONS OF ERATOSTHENES: Factual or misquoted, an investigation. The River Nile measurements and the Oikoumene.

Strabo’s “Geography” Book 17, chapters 1 to 4 discuss Egypt and in particular the River Nile. The data is primarily that of Eratosthenes, but, even though Strabo has sailed the Nile it is still mis-understood and obviously the text is later corrupted by copyist errors.

This paper analyses the River Nile measurements, determines that as Eratosthenes knew of them he had no necessity to rely on the “Aswan Well” phenomenon to determine the degree of Latitude and hence the world circle. The fact that “Egyptian Cord-Stretchers” had obviously measured or determined the world circumference centuries before Eratosthenes is then illustrated.
Finally the length of the Stadion utilised by Eratosthenes, illustrated first in Text Es1, is confirmed and the breadth of the Oikoumene discussed.
8 A4 pages and 5 full colour diagram maps

April 2010
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September 2010 - Texts Mt1 and Mt2 would normally be inserted here to ensure that the chronology of the texts is maintained. However because of their content, which is based upon the text of Claudius Ptolemy, they have been uploaded in draft order only.
350 354

CLAUDIUS PTOLEMY: FALSIFICATION, REGIMENTATION OR SYMMETRY: An investigation into the form of Britannia and the Turning of Scotland whilst maintaining the Latitudinal and Longitudinal co-ordinates.

The map of Britannia that can be drawn using the co-ordinates of Latitude and Longitude given by Claudius Ptolemy in Book 2, chapter 1 of “Geographia”, produces a picture of Britannia that is both reasonably in agreement with, and at the same time wildly inaccurate of geographical fact. This paper introduces a methodology for comparing the correct geographic form of Britannia to the Ptolemaic form. It analyses the geographical and Ptolemaic locations of both coastal and “poleis” positions and determines a correspondence for each. It then illustrates how simply the “Turning of Scotland” was achieved, such that the reversal of the co-ordinates was possible whilst maintaining the juxta-positions of individual locations.
12 A4 pages and 12 full colour diagram maps

April 2010
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381 387

THE MEDITERRANEAN SEA OF MARINUS OF TYRE AND CLAUDIUS PTOLEMY: An investigation into the methodology and distance measure utilised to control the Latitudes but expand the Longitudes thus accommodating the actual littorals.

When Marinus of Tyre and Claudius Ptolemy determined the Earth’s circumference as 180000 Stadia of c184 metres, they created an un-avoidable mis-representation of the correct or geographical world. Coastlines in the Mediterranean Sea which had been sailed for millennia and the distances known, had to be reasonably correctly portrayed. Therefore if the Latitudinal spread of the Sea was curtailed by a reduced circumference, then the longitudinal spread had to increase to accommodate the semblance of reality required for a true map. How this increase was managed, how the land forms of countries were manipulated and where the data was obtained in the first instance, are the subjects discussed and illustrated in this paper. There is also a sub-section section dealing with the measurement of the World, which if Marinus and Ptolemy had actually investigated, by physical measurement, would have led to their producing the most accurate of maps.
18 A4 pages and 17+1 full colour diagram maps

April 2010
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INDIA INTRA ET EXTRA GANGEM + SINAE: The maps of Claudius Ptolemy explained and the resolution of place-names including Taprobane and Cattigara Sina

As the maps of Claudius Ptolemy are studied, commencing with Britannia, then the Mediterranean Sea littoral and Arabia with the Middle East, there is a very recognisable profile to each when compared to a geographical map. However, when the map described in Book 7 chapter 1 is constructed, that is,” India this side of the Ganges”, a complete and utter travesty of geographical fact emerges. The following section, “India beyond the Ganges” returns to a semblance of geographical fact. Why should this be? Why suddenly do we see a childlike scribble purporting to be the coastline of India? India is basically a south pointing triangle, and it is drawn in the form of a demented snake. The solution is remarkably simple and provides for a methodology to determine the location of Cattigara Sina, and determine where and which island is Taprobane.
12 A4 pages and 8 full colour diagram maps

April 2010
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439 441

THE TEXT OF MARINUS THE TYRIAN AND CLAUDIUS PTOLEMY: ”Geographia”, Book 4, chapters 1,6, 7 and 8. The west coast of “Libya” explored, the Zero longitude determined and the East Coast capes located.

Ever since Claudius Ptolemy named one of the Fortunate Islands which he had situated on the Zero Longitude “Canaria”, cartographers have assumed that the Canary Islands off the west coast of Africa are the Zero point. That is patently incorrect. It can be simply illustrated by a re-reading of ancient texts referring to the sailing voyages around Africa, and then the utilisation of a comparative scale map. The East coast of Africa is then examined in a similar manner with the Capes listed by Ptolemy as the final locations on the coast determined to a geographical point. There is then an appendix to the paper which discusses the ratios adopted in the map construction of Claudius Ptolemy, particularly the major world ratio figures and concludes with a discussion on the methodology of constructing a world map.
11 A4 pages and 6 full colour diagram maps

April 2010
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447 459

A LINE ON THE LANDSCAPE: Travel with “Michael” from Italy to Ireland. The Roman World Survey and its aftermath.

This paper considers the circumstantial evidence for a Mappa Mundi of Roman origin and introduces a methodology for examining that possibility. Julius Caesar (100-44BC) ordered that a world survey be carried out to establish the extent of the Roman Empire and perhaps the adjoining lands which as then had not been conquered. Following the commencement of a new era, BC/AD we find cartographers such as Marinus of Tyre and Claudius Ptolemy producing quite remarkable maps, with for the era an un-paralleled accuracy. Although evidence of the Roman survey is limited, it can only be from official Roman sources that those two cartographers received their latest data. Thus by analysing the works of authorities who succeeded the Romans, such as the Early Christian Church, we can perhaps establish the veracity of the historical texts. Fortunately, those works can be examined by a study of a landscape phenomenon which can only exist because there was a map of sufficient quality and accuracy to allow the concept discovered to be formed. By studying the positions in the landscape of Early Christian edifices of a particular nature, noting the methodology and metrology used, it is possible to conclude that there was a Roman Mappa Mundi dating to the BC/AD interface.
8 A4 pages and 6 full colour diagram maps

April 2010
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461 469

WHEN RECTANGLE SUPERSEDED TRIANGLE: Britannia in ancient texts, The Venerable Bede and the Tabula Peutingeriana.

There is hidden within early texts, which at first glance would not be thought to contain such information, data on cartography. This paper considers the possible relevance of the Venerable Bede’s (AD672-735) concept of Britannia to cartography, his comprehension of the original data, and why that may have affected his view of Britannia. The information also provides us with an opportunity to construct an alternative for the lost portion of the Tabula Peutingeriana, as it applies to Britannia, Iberia and North Africa, which constitute the missing portion.
8 A4 pages and 4 full colour diagram maps

April 2010
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471 473

THE GOUGH MAP: AN INVESTIGATION: The provenance of a historical ‘tour de force’ in English cartography.

The Gough map stands alone as a work of immense clarity. But, it is an enigma which requires examination to enable a comprehension of the knowledge available to the original mapmaker. The scale and relative disposition of geographical features must be known, but, apparently any such data normally appended to a map, such as guidance lines (if they were ever drawn) are missing. This may be a simple omission due to a later cutting of the map base skins.
Previous investigations of the map fundamentals have indicated accuracy in the overall concept and dated the map to c1360AD. This paper considers just how the data to draw such a map may have been collated, how it was drawn and the basic parameters underlying its construction. The conclusion is that a paradigm shift in our thoughts is required concerning the availability of ancient data.

12 A4 pages and 16 full colour diagram maps

April 2010
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Text Gm2, the Gough Map technical data from Gm1 "How it was drawn", is now included as Gm2 further on this page
495 511

THE SAXTON MAP, 1579 AN INVESTIGATION: Information for a large number of maps was surveyed, engraved and published in an amazingly short length of time for the era and tools available. Just how was this achieved with considerable accuracy, and what followed?

The general map of England and Wales has hidden within its format the basic concept from a century’s earlier survey. Drawn first without its latitudinal or longitudinal bordure scales, the Saxton Map has centre lines which are at variance to the later added bordure. When the actual degree marks were added they conformed to the spirit of cosmography, with tapering longitudes, but were arbitrarily chosen to suit a differing context. The map is a straight forward depiction of England and Wales drawn to Ptolemaic principles and illustrates the confusion within the sixteenth century regarding distance measure that is now the Statute Mile.

12 A4 pages and 16 full colour diagram maps

April 2010
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515 518

RESEARCH INTO THE METHODOLOGY OF CLAUDIUS PTOLEMY: Has computerisation led to a systemic failure in the simple comprehension of the very basic nature of the data in the “Geographia” of Claudius Ptolemy?

Many papers, subject matter cartography, and more particularly those concerning the methodology of Claudius Ptolemy now include the “de rigueur” utilisation of computer programmes, computer generated visualisations and the Star Burst Plots which endeavour to illustrate data comparisons. That this usage of the computer does not of itself appear to offer any additional information to the subject matter and is merely presentational, should perhaps give cause for reconsideration by those authors of its usage.
This paper is not a polemic against the use of computer generated data, which certainly has its place when appropriately used. It is in fact questioning the over complication caused by such usage when simple maps or diagram maps used as the prime research tool would actually explain more.
This paper illustrates that by comparing maps based upon the same projection, and with the use of only simple maps (for that is all that Claudius Ptolemy has bequeathed to us) a fuller understanding of “Geographia” can be gained.

9 A4 pages and 2 full colour diagram maps

April 2010
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526 528 538 551

WILLIAM STUKELEY, ANTIQUARIAN; MAP OF 1723 Herman Moll, Engraver and Cosmographer

William Stukeley FRS, FRCP, FSA (1687-1765) was a multi talented individual who is now best known for his dissertations on Stonehenge and Avebury. He also wrote several texts concerning the Antiquities of Britain and in 1724 published, “ITINERARIUM CURIOSUM. Or, an account of the antiquity and remarkable curiositys in nature and art, observed in travels through Great Britain”. This text includes the 1723 map.

Herman Moll, engraver and cosmographer, (probably Dutch 1654-1732), moved to England and composed his atlas comprising “fifty new and correct maps of England and Wales”. Within that text, “A NEW DESCRIPTION OF ENGLAND AND WALES”, published also in 1724 he included the Stukeley map. He was also a well known figure in the London Coffee Shop society of the age.

Comparisons of the two maps and their drafting indicate the knowledge of the era.

4 A4 pages and 10 full colour diagram maps

June 201
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559 562

WHEN WAS BRITANNIA A RECTANGLE? Early texts analyzed and maps investigated

There is a surprising amount of geographical information in the early texts; both Roman Latin and British Latin, which if analyzed indicate a changing description of Britannia. That change is from a Triangular shape to a Rectangle. Why?
These two shapes are hardly compatible. Thus this speculative paper is a hypothesis on the reasons for the change, its basis in fact, and its record in the early maps.
It is also one of three texts which combine to explain the early map history of Britannia.

9 A4 pages and 12 full colour diagram maps

June 2010
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588 590

BETWEEN PTOLEMY AND BEDE, JUST WHERE IS IRELAND? An examination of it’s textual positioning

Continuing the theme of using early medieval texts to evaluate cartographic knowledge, this paper examines the textual descriptions of Ireland and its relationship geographically to Britannia.
It is again speculative, a hypothesis to answer the many diverse descriptions in those texts and to understand how they may have originated.
It is the final chapter in the investigation of Britannia and Hibernia apropos their geographical size and location, but not the last paper regarding the landscape positioning of religious establishments commenced in text StM1.

5 A4 pages and 7 full colour diagram maps

June 2010
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600 643


 This paper is a continuation of research within my texts Cp2 and Cp3. In his Geographike Hyphegesis, Ptolemy sets down the length of the oikoumene attributable to Marinus the Tyrian. In so doing we find two major pointers which can be utilised to ascertain how Marinus calculated this length.

Firstly, as already evidenced by research in texts Es1, Es2 and Cp3, the Eratosthian Stade of c157.5 metres is used by both Marinus and Ptolemy with their mapping of at least India.

Secondly, in the text of Ptolemy we read that the two eastern distance measures, to and from the Stone Tower are itinerary measures, and thus it is possible to confirm that Marinus has used the same methodology as Eratosthenes of Cyrene to calculate and thus establish his oikoumene; Itinerary measures.

12 A4 pages and 7 full colour diagram maps

September 2010
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The map of Marinus the Tyrian is in fact the map used by Claudius Ptolemy but drawn on a different graticule. A simple investigation of the text of Claudius Ptolemy reveals that fact. Also indicated, despite the protestations by Ptolemy concerning the length of the oikoumene given by Marinus, is the fact that Ptolemy actually uses the same length, although he tries to hide the fact, to determine his oikoumene of only 180 degrees.

16 A4 pages and 13 full colour diagram maps

September 2010
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Variously praised as, ‘the most important medieval map of Britain’, or ‘the earliest surviving map to show the island of Britain in a geographically recognisable form’, and ‘the oldest surviving road map of Great Britain’, the Gough map has been the subject of much scrutiny over the years. But no researcher appears to have dissected the map, deduced its foundations and then endeavoured to redraw it, metaphorically and physically, to prove their findings. This paper reports on such an attempt and the surprising results.

10 A4 pages and 12 full colour diagram maps

May 2014
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653 657 661 688


The population of France was by the seventeenth century approaching 25 million inhabitants, making it the largest in Europe. There was also, as now, a very large forested area which did not permit crop growing and therefore the production of food for the populace. Thus, land which would not normally have been utilized for general farming was subdivided and where possible even vines were planted. But in general this land was only fit for grazing animals, mostly sheep. This usage continued from the Ancient Regime through to the First Republic and its provenance can be traced by the extra-ordinary land form it generated.

8 A4 pages and 9 full colour diagram maps

April 2010
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701 703

FOLLOW THE BARLEYCORN: The Beginnings of Metrology

Practically everything we do in life requires measurement. That measuring of anything requires metrology. In cartography we use all forms of measures, metrology, mathematics and geometry to form the maps and data we wish to portray. Without measure there would be no scale or proportion.
Where the original measurements came from is a fascinating historical journey which indicates just how adept our forefathers were when faced with the necessity to compare goods.

5 A4 pages and 4 full colour diagram maps

May 2010
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762 764


There is a very large gap in the historical records regarding the metrology of ancient Britain, and England in particular. That the Romans came, imposed their standards and left is totally recorded and dealt with at length in hundreds of scientific or archaeological papers. That the ancient Britons built quite fantastic monuments of wood or stone is also totally recorded. What is missing from the record however is how ancient man controlled the construction of those monuments, the measures utilized to plan and then produce wooden beams and shaped stones to fit quite precisely into position? Even when archaeologists and historians have the evidence in front of them it is often ignored because of a lack of metrological training. This paper seeks to redress the balance and explore the possibility of a coherent megalithic metrology.

Powerpoint Presentation

14 A4 pages and 11 full colour diagram maps

May 2010
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768 770

AN EXPLORATION OF THE BEGINNINGS OF METROLOGY The number 7 and irrational numbers √2, √3 & PI

Megalithic measurements which are derived from Stone or wooden Post circles have generally been denigrated. Archaeologists have not bothered to investigate if there could be a quantum measure, holding to the line that until a measuring stick is excavated there is no proof; Historians have generally ignored the subject, many being unfamiliar with geometry. Some mathematicians have entered the fray both for and against the possibility.
Even today if the term Megalithic Metrology is inserted in a search engine the general response is to place it on-line with a sub-title “pseudoscientific metrology”.
However there are too many coincident measures to dismiss the possibility so lightly.
The texts Ms2 and Ms3 endeavoured to show by example the possible measures and their inter-connectivity. This paper explores their probable origins.
This paper presents research, speculation, as is only possible now, and takes its ethos from the Latin,
Uno itinere non potest perveniri ad tam grande secretum.
It is impossible to solve so great a puzzle by using one route only!

6 A4 pages and 5 colour diagrams.

June 2010
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777 779


Within my text Ms3, “What came before the English Statute System, not Roman, but Megalithic measures”, I limited the discussion concentrating solely on Britain and Europe, with a minor comment about Mohenjo-daro. This paper commences at the very beginnings of survey measurement in Mesopotamia, c4000 to 3000BCE, then introduces Indus Valley measurements , before discussing Megalithic Europe in a cursory manner this time; it then moves to Mesoamerica and finally to the Mississippian culture of the southern USA.

My original texts on measurement, Ms2, Ms3 and Ms4 are to be found on this page. They are also on my Academia.edu page; with all papers free downloads with diagrams. I would urge anybody interested in this subject to look at Ms3 and the Power point presentation of the text prior to reading this text.

This text is 11 A4 pages and then there are 17 A4 diagrams.

September 2016
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791 793


In 1481 Pope Sixtus IV confirmed in his Bull, “Aeternis Regis”, the sphere of influence for Portugal and Spain in the Atlantic Ocean. This eventually became known as the Line of Demarcation. In 1495, Jaime Ferrer [1], cosmologist, wrote to Their Majesties of Castile two letters explaining the 370 league distance measure that was incorporated in the Bulls. In 1528, Jean Fernel, a Frenchman, wrote “Cosmotheoria” [2], a text dedicated to King Jaoa II of Portugal and there-in indicated a methodology to determine a degree of latitude measurement. Both however indicated a spurious measurement consisting of 700 stades which was derived from Eratosthenes “Geographia”. There was therefore in that age a complete lack of understanding of the measurements and thus errors in research. However, the greatest problem appears to be the research into the voyage of 1492 and the distance measure of C Columbus described in various terms but never detailed correctly.

The whole text is 17 A4 pages including appendices and 3 diagrams.

March 2017
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806 809

Monalosphaerium; Cosmotheoriae & de Proportionibus J F Fernel, Measurements; Accuracy & Fantasy Abound

J F Fernel wrote three texts which indicate his first studies, mathematics and astronomy. Here-in they are evaluated, but only “Monalospharium” and “Cosmotheoriae” are completely investigated, whilst “de Proportionibus” is simply explained. Thus the measurements involved, the length of a degree of latitude and basic geometry, which includes Euclidian methods are all discussed. It is obvious that J F Fernel is using the work of Claudius Ptolemy, he notes the Almagest text, but his greatest usage is of “Geographike Hyphegesis” when he discusses latitude and longitude, although somewhat at variance.
However all three texts as published are full of errors; the figures are awry and the calculations leave a lot to be desired with a lack of explanation of their basic components.
It is obvious from the construction of the three books that they were compiled between c1520 and 1525 thus allowing publication in 1526 and 1528. The errors are twofold being both original and printer/publisher as the errata do not cover the most obvious. Thus it is clear that the three books were written from notes taken over the 5 years, transcribed at a later date and thus errors were made. However the idea and work involved in measuring the land surface to determine the degree of latitude cannot be criticised; it is a pity as will be shown that a modicum of inaccuracy crept into the methodology and J F Fernel was swayed by spurious measurement comparisons. Some never actually existed and are mathematical enigmas. Basically all three texts require to be carefully read before accepted as correct.
The text is 17 A4 pages and contains 15 A4 diagrams.

June 2017
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812 816

FROM THE DEE/ HUMBER TO THE SOLWAY/TYNE; AD79: The Roman disposition of Fortresses and forts, and the survey technique uncovered.

The normal interpretation of “De Vita Agricolae” written by “Cornelli Taciti”, the history of the Roman conquest of Britannia, is that after subduing the south and midlands, the land either side of the Pennine Chain was to be subdued by a two prong assault from Chester and York. This two fold assault required cross Pennine contact via valleys and passes and required that forts be strategically and locally positioned. The positioning of these forts illustrates Roman Military survey skills which have not been explained in extant literature.
This paper illustrates the survey and planning by the Roman Army in the landscape of Britannia indicates that a large amount of data is missing from extant histories.
It also illustrates that the Roman Army had and made excellent maps.

8 A4 pages and 13 full colour diagram maps

April 2010
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844 847


The Roman method of aiding retired legionaries was to set up a “Colonia” or just a Civitas and auction by lot land parcels for self sufficiency. These land areas formed a territory and it is possible to establish their boundaries by landscape archaeology, through extant boundaries and constructions. This paper looks at two such areas which form part of the Foss Way, England; a well known Roman Road.

7 A4 pages and 9 full colour diagram maps

June 2010
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908 910


The Groma is a surveying instrument utilized by the Roman Agrimensors or Geometres to align the boundaries of fields and general areas. It was used to set out the original land divisions as well as check their veracity after years of farming and thus to resolve land boundary disputes. It is well documented, but hard to establish in practice as a physical object. Thus the papers so far written are perhaps lacking in practical assessment of its utilisation in the field. This paper analyses the evidence by practical application, and assesses the likely construction.

The text is 4 A4 pages and 3 full colour A4 diagrams.

June 2010
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913 915


The texts concerning the work and methodology of the Roman Agrimensors or Geometres are contained in a variety of extant manuscripts which have been well studied. However, when one these manuscripts is analysed with a practical surveyors appreciation of the finer points of field work, it does not stand up to scrutiny. This paper endeavors to unravel the mystic from the practical and cast light upon the actual practical works of those Agrimensors.

The text is 6 A4 pages and there are 16 diagrams, some of which are full colour.

June 2010
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917 919


Codex Arcerianus ‘A’ contains many Latin texts and particularly works by Hyginus Gromaticus. One would perhaps assume that with a surname taken from the Roman surveyor’s instrument, “The Groma”, any text written by him concerning survey techniques would be correct and to the point.
I have already shown (in text Rm4) that is not what we find when reading these texts. It would appear he was more a mathematician and geometrician than a surveyor, and wrote accordingly.
This text (part A) concerns the technique of establishing N S E &W using a gnomon and three shadow lines from the Sun’s rays. It is a mixture of practical work, knocking in a post or gnomon, and drawing work. As such, it would be extremely difficult to combine and carry out in the field.
Thus we see a theoretical concept transformed into a supposed practical concept, and failing. When in the field surveying alignments for a new Territorium or similar, it is best to keep all techniques as simple as possible, using the minimum of equipment.
The second part of the text (part B) examines the actual physical process of surveying the main points, Decumanus and Kardo Maximus, and discusses the knowledge required by an Agrimensor.

The text is 7 A4 pages and there are 14 diagrams, some of which are full colour. The paper is presented with the diagrams within the text for easier comprehension of the survey technique involved.

December 2010
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921 923


Within the 10 books comprising ‘De Architectura’, Vitruvius discusses the many and varied subjects which comprise the genre of Architecture. However, it is not a complete text for the subject.
From his own words we know that he copied or at least based his work on the texts of the authors listed in Book 7, chapter 7. Thus the simplest comment to be made is that he perhaps thought he was compiling an encyclopaedia of Roman design and building techniques. But that is not the resulting book.
That Vitruvius does not fully understand what he is writing or copying is amply illustrated in this text whilst sampling the data provided. I also endeavour to understand why, when writing such a treatise dedicated to Octavian/Augustus Caesar he is so parsimonious in his words, and why it takes until Book 6 for Vitruvius, writing about Architecture, to explain in a rather round-about way that his education included art and physics. If you are trying to influence or convince an emperor of your credentials, do it on page one, not after he has had to read 5 Books to find out if the author, (even though that author professes the he is known to Caesar), has the credentials to write the text. Therefore it is quite in order to ask why, and look at all of the other missing data, so carefully avoided.
This text does not analyse Book 5, Public Buildings, which is the subject of a third text referenced RmVt3. A short text reference RmVt2 discusses the Measure of Man, from Book 3, chapter 1.

The text is 26 A4 pages and there are 44 diagrams, some of which are full colour.

July 2011
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935 968


Vitruvius in his 10 books of architectural theory chooses to open Book 3 with a comparison of the design of Temples and the Human form. Within paragraphs 2 and 3 of Chapter 1, Vitruvius lists various dimensions for the human body and describes how the form can be encapsulated in both a square and a circle, which are two separate entities.
Leonardo Da Vinci cleverly incorporates the two entities as described by Vitruvius into one iconic diagram, Vitruvian Man.
Leonardo’s short text accompanying his diagram details the assumptions and lists the measures he has used. These differ from those of Vitruvius.
Both sets of diagrams require geometry to explain their raison d’être.

The text is 4 A4 pages and there are 5 diagrams, some of which are full colour.

August 2011
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974 976


In text RmVt1 the general text of Vitruvius was discussed, who was he, his career etc., and it analysed various parts of the technical text of DE ARCHITECTURA.
This text is solely concerned with his description of the Basilica at Fanum Fortunae, its situation and design, as can be analysed from the text.
Necessary for this investigation is a historical time line for Fanum Fortunae, in the broadest of terms only.
The design of the Basilica is then diagrammatically illustrated to include all of the elements that Vitruvius details. However it is not an attempt to finalize a design. It is merely a guide, as the various translations from the original text of Vitruvius and his archaic technical Latin, when read in the English language, are so very different in their content and meaning.

The text is 13 A4 pages and there are 16 diagrams.

August 2011
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978 980


From the centuries BCE, Cosmographers, Geometres and historical authors bequeathed to us a variety of facts appertaining to their known world, the oikoumene. Most of the measurements were obtained by the traditional methods, “day’s travel” or “day’s sailing”. There existed though trained surveyors, “Bematists” who by accurate pacing measured progress and “Cord Stretchers”, whereby precise measures were obtained.
Herodotus tells of expeditions and maps extant in the 7th to 5th centuries BCE, and Hecataeus of Miletus, C550-476BCE, was able to write his books entitled “Ges Periodos”, “travels around the earth”, as a Periplus.
Various other Cosmographers, Geometres and historical authors added their own text, or recycled previous author’s work, to add to the corpus of information accumulating. This was mainly gathered at Alexandria after the formation of the Ptolemaic Dynasty in Egypt.
The collation of many facts led to perhaps the first of the scientific world measures, that of Eratosthenes, with his famous method and cosmography.
Then Rome became the all powerful state, absorbing Greek “Gnous”, and by 60 BCE dominated the Mediterranean lands. Julius Caesar then consolidated the Roman Empire.
But that Empire was perhaps intangible to many Romans, being only names on parchment. Thus Julius Caesar instructed a formal World Survey, choosing four Greek Geometres for the task and gave each a cardinal segment. But, having given those instructions he was infamously slain in 44BCE, and his adopted son, now Augustus Caesar, completed the task and by 6BCE a map was displayed in Rome.
Then soon after the commencement of our common era, Strabo, c15CE, wrote his “Geography”, based upon the work of Eratosthenes, but added his own travels and observations. Pliny the Elder, c75CE, wrote his “Natural History”, which was based upon the Roman Survey and its aftermath, and in c100CE, Marinus the Tyrian wrote his “Geography”. That text is the basis of the work by Claudius Ptolemy, his “Geographike Hyphegesis”, c150CE, the only extant cosmography now available from that period and used by most cartographic historians.
Then slowly but surely a new and possibly intellectual sect appears, Christians. The Roman Empire wains and is defeated by Odoacer in 476CE, but by 391CE Rome had already accepted Christianity as the state religion. Thus we can observe one state ruled by a Caesar being supplanted by a nebulous state, but ruled by a Pope and taking on the trappings of Roman technology, using their survey methods by studying the texts of the Agrimensores and Geometres. Later the formalisation of Monastic establishments into one design followed the Roman Army principle of identical layouts, such that peripatetic soldiers and the monks could locate their place easily in a new establishment.
Thus the Roman World Survey which had gathered in extant knowledge, then amplified it with new research, enabled following generations to progress both with formal surveying and cartographically.

The text is 14 A4 pages and there are 4 diagrams embedded

Powerpoint Presentation

October 2011
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989 991


Pliny the Elder, Gaius Plinius Secundus (23CE-August 25th, 79CE) was a Naval and Army commander and friend of the emperor Vespasian. Pliny’s last text was the “Naturalis Historia” completed in 77CE. It is an encyclopaedia of available knowledge and comprises History, Geography, Botany, Zoology, Astronomy, Geology and Mineralogy.
Unfortunately his sudden and unexpected death whilst endeavouring to rescue persons trapped by the eruptive force of Vesuvius meant that this text was both perhaps his greatest and last.
The geographical fragments included there-in, are from many sources; each is attributed to the original author and traveller as the case may be. These people generally existed just before our common era, but also as far back as Eratosthenes (285-194BCE), and thus provide a marvellous insight into the Geography of that age. It pre-dates the work of Marinus the Tyrian and Claudius Ptolemy, who were active from the end of the first century to the latter part of the second century CE, but, it is contemporaneous with the “Geography” of Strabo. However, it appears that Pliny was not aware of that text.
This text is not a comprehensive analysis of Pliny’s work, but a selective overview to establish the overall extant world view that appertained in the first century of our common era. It is also the pre-cursor of a second text, cgPl2, which investigates the map or maps available to and studied by Pliny.

23 A4 pages and 21 full colour diagram maps

February 2011
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1057 1059

THE ARAL, LAKE or SEA; AN ENIGMA! Cartographically unknown—physically lost!

The Sea of Aral has been the subject of much speculation regarding the shrinkage of its limits so evidenced by the enigmatic photograph of the ships high and dry in a desert scene.
This paper only discusses the fact that the Sea of Aral does not appear on western maps until the 16th century, but was shown on Eastern or Arab maps in the 12th century.
When the general area was mapped by Marinus the Tyrian and Claudius Ptolemy c150CE there was a conflation of the Caspian Sea and the Sea of Aral. Why?

11 A4 pages and 10 full colour diagram maps

February 2011
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1073 1075


Marcus Vipsanius Agrippa was tasked with the production of a map, not a map of the Roman Empire c20BCE, but a map of the whole known world.
Pliny the Elder wrote his reference work, “Natural History” c77CE, well after the death of Agrippa in 12BCE. But, Pliny obviously viewed the finished map which had been erected or displayed in a public area, the Porticus Vipsania.
The source of the geographical data within Pliny’s text is mostly attributed to Agrippa and appears to come from the commentary written to accompany the world map.
Thus by extracting the data attributable to Agrippa for geographical, and then the astronomical/astrological facts contained within Pliny’s text, we can unravel the dubious extant reconstructions of the past and indicate hitherto un-researched facets of the text.
This has enabled a new interpretation of those facts to be made, and thus the possibility to describe and draw a map more akin to the original by Agrippa.
The previous text, cgPl1, contains much of the research for this text. It has not been repeated, merely referenced.

17 A4 pages and 24 full colour diagram maps

March 2011
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1079 1081


The text of Claudius Ptolemy within Book 2 has a well ordered methodology of presentation. However, that only applies to the first 9 chapters and then chapters 11 to 15.
Chapter 10, Magna Germania, is treated in a different manner. Why?
This area of Europe was not conquered by the Roman legions and therefore geographical knowledge was not available to Claudius Ptolemy. Did he therefore invent a geographical landscape?

18 A4 pages and 12 full colour diagram maps

August 2011
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1100 1102


The Histories” deal with Greek/Persian conflicts until c430BCE, the first year of the Peloponnesian War.
“Herodotus of Halicarnassus, his researches are here set down to preserve the memory of the past by putting on record the astonishing achievements both of our own and of other peoples; and more particularly, to show how they came into conflict.”
Those are his first words, and after them is a Geographical, Social, Religious and Mythological treatise concerning the world known to Greeks and Persians. He is known as the “Father of History”, and sometimes criticised for his “outlandish tales”, but, many have subsequently proven correct.
This text analyses and comments upon most of the geographical facts contained there-in.

17 A4 pages and 13 full colour diagram s

February 2012
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1121 1124


Paulus Orosius, born c375CE, was a Christian historian who perceived that the Roman Empire was in decline and the new religion of Christianity was in the ascendance. To assert that point he was charged with writing a History to show that the Christians were by no means responsible for the catastrophes which had taken place under pagan (Roman) rule.

In c313 CE the Edict of Mediolanum (Milan) was in favour of equality for Christians and it eliminated the cults of the Roman State. By c395CE there are established two Roman Empires, those of the East and West, with Constantinople as the eastern capital. But as with later texts written by Monks (Tp1), he begins his ‘History’ with a complete description of the known world. It is only that text which is herein analysed and can be shown to be an attempt to describe the oikoumene c400CE from east to west with the three continents as divided in the ancient Greek world of c600BCE. But in many instances it is a lightweight description. However, there are facets of that description which are intriguing, particularly in their provenance.

19 A4 pages and 14 full colour diagrams

May 2012
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1145 1148

Al-Idrisi; The Book of Roger The description of L’Angleterre

The Normans forged an empire from their beginnings in Northern France, when in 911 King Charles the Simple (898-923) agreed that the Vikings (original Normans) under Rollo should receive land in France. It was then called Normandy, and as such was a Duchy within his realm. The Normans were content for a short period of time and then around 1016 expanded their sphere into southern Italy and Sicily. By 1095 Roger 1st was Count of Sicily. Roger 2nd began his rule after the death of his brother and in 1112 was Count of Sicily and Calabria. Meanwhile from their latter homeland of Normandy, Duke William invaded L’Angleterre and made it his fiefdom in 1066, with a Domesday Survey following in 1086.
Roger 2nd however was situated in the centre of the Mediterranean Sea, Sicily, with to his east south and west lands that were Arab Muslim States. Thus Roger 2nd could draw around him learned persons of many races and through them collected information regarding the Oikoumene.
Having collected sufficient data he instructed an Arab, Muhammad al-Idrisi to produce a map of the Oikoumene and a Geographical treatise containing a full description of all facets of that Oikoumene.
This first investigatory text solely concentrates on the description of L’Angleterre and the sparse information included in the section which also deals with Ireland and Scotland. That is Climate 7, Sections 1 and 2 of the text by al-Idrisi.

20 A4 pages and 16 full colour diagrams

October 2012
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1245 1249

Al-Idrisi; The Book of Roger The description of Al Andalos

The text by Al-Idrisi within the ‘BOOK OF ROGER’, (a sub-title of its Arabic title), is loosely divided into 7 Climates each being theoretically 9 degrees of latitude. Each Climate is then divided into 10 sections each being theoretically 18 degrees of longitude. Al-Andalos or Spain in this text comprises the whole Iberian Peninsula and is described within the 4th Climate, 1st Section and the 5th Climate, 1st Section; these two Climates basically divide the peninsula in half latitudinally.

It is a highly detailed description comprising 81 pages in French translation and is by far the most expansive description of any country or area within ‘The Book of Roger’.

But that description, even though Al-Idrisi is well aware of the country of Al-Andalos, is faulty; that is because of the words he has chosen to portray the shape of the Peninsula. Al-Idrisi uses the term “triangle” and then qualifies it pages later with the words,”we say therefore that the form of Spain, in the most extreme use of the term may be described as a triangle.”

The damage however had already been done and subsequent scribes portrayed Spain as a triangle. Al-Idrisi also used a metaphor which may also be considered suspect to describe L’Angleterre as being of an Ostrich Head shape as is discussed in the text cgId1. This text cgId2 endeavours to redress the wrong impression given by Al-Idrisi with his faulty metaphor, his somewhat throwaway description of Spain, and use his own text to indicate how he actually viewed the Peninsula and probably drew his map of it. It is obvious that it was not viewed as a triangle.

15 A4 pages and 28 full colour diagrams

November 2012
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1254 1256

Al-Idrisi; The Book of Roger ‘Orphan’ Circular World Map

The prologue to “The Book Of Roger” contains a description of the desires of Al-Idrisi concerning a world geography and map and how he will set about achieving it. He desires to fully explain the oikoumene, its lands, geography, seas and peoples and to illustrate the form of that oikoumene on a series of tableaux, individual maps, each being a specific part of that oikoumene.

He determines to subdivide the oikoumene into 7 climates and infers that this is as Claudius Ptolemy described. That is the first of Al-Idrisi’s sleight of hand. He then decides that each climate will be sub-divided into 10 equal sections of the full extent of each climate from west to east.

In his text he clearly states that there will be 70 tableaux or maps.

What Al-Idrisi never states is that his text will also contain a single map to accompany” The Book of Roger” which will represent the oikoumene, the co-joining of the 70 tableaux in the form of a circular map with the 7 climate lines appended.

But, each copy of “The Book of Roger” contains such a map. Who’s Map?

The circular map, similar in size to a tableau is geometrically constructed to give a partial view of a globular world upon a flat sheet of paper, where-as the 70 tableaux are drawn as if the world was flat in a rectilinear projection. The Preface of Al-Idrisi hints at an answer to the foregoing points and is fully discussed within the following text reference cgId4.

This text endeavours to determine the origins and construction of the singular circular world map and the climates used by Al-Idrisi, none of which is accounted for by him.

9 A4 pages and 18 full colour diagrams

November 2012
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1263 1265

Al-Idrisi; The Book of Roger Preface, prologue and 70 maps

The preface by Al-Idrisi to his text concerning the geography of the world, named “The Book of Roger”, is an exercise in hyperbole that any current publicist would be proud to have written to enhance the reputation of Roger II of Sicily.

The prologue is a different matter. There-in we read of the size of the oikoumene, of the seven (sic) climates and a brief description of features of that oikoumene.

It is as if the two sections were written at very different stages of the overall work that Al-Idrisi carried out for Roger II of Sicily. They are not contiguous in what purports to be a single homogenous text.

Al-Idrisi sets down towards the end of his very short preface details of a drawing board being prepared and iron compasses used to draw a world map. This is to become the silver planisphere model. However, he issues no instructions for the construction of the planisphere other than its metal weight.

Then in the last paragraph of the prologue he sets down that there will be 70 maps to describe the oikoumene ‘without counting the two extremities of the oikoumene’. But as text cgId3 explains there are in fact 71 maps within the text, with the 71st being a small scale circular world map which may be considered an instruction sheet for the amalgamation of the 70 tableaux. It serves no other purpose.

But the 70 maps spread throughout the texts vary in content. The oldest text available is ARABE 2221 held by the BnF in Paris, and is dated to c1300. That is some 150 years after the original was written, but the diagrams do appear to agree with the Pococke 375 text, which is another 150 years later, and is held by the Bodleian Library, Oxford.

H owever, Konrad Miller collated the Al-Idrisi maps and prepared a restoration and transliteration in 1927 (Arabic/ Latin/ German) of them, but his reconstruction uses maps with extra information appended.

Thus we can examine the overall map of Al-Idrisi formed by the 70 tableaux and set it against that of Marinus the Tyrian and Claudius Ptolemy, who Al-Idrisi states determined the figure of the Earth.

14 A4 pages and 21 full colour diagrams

November 2012
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1268 1270


An overview of English Maps c1300 to c1760 which will be followed in a later paper (cgEm/O) by essays describing the peculiarities to be found on specific English maps. This text concentrates upon the form of Britannia, sans Scotland, its development and accuracy and includes a discussion of map scales used.
It also contrasts the form of Britannia as shown on each map with a Geographical Ptolemaic map drawn for just that purpose. There is one curiosity however that may not be resolved, but, with two possible answers, very simple possibilities of which William of “Occam” would approve the enigma can be discussed.

16 A4 pages and 27 A4 diagrams.

July 2013
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1309 1311


The preceding paper cgEMGn1 was an all encompassing discussion of English Maps, their form, heritage and interdependence. This text subjects several of those maps to greater scrutiny via individual essays. The maps may be considered both singular or as being exemplars for English map-making.
The essays discuss how the maps were constructed, their foibles, the bordure scales which are certainly not always reality and the variable north point.
One text is written as a full analysis, not an essay, and completes the papers.
There is also a comparison with European Cartographers who have drawn maps of England and Wales and have the same scale problems for longitude as the English maps.

14 A4 pages and 34 A4 diagrams.

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1349 1353

1457 World Map; Genoese, Yes! Draughtsmanship before History

The planisphere known as the Genoese World Map, 1457, has no known author or actual place of production. It has been assumed by some researchers to be of Genoese origin, but this is contested. This text indicates from within the planisphere itself its point of origin and how it was constructed by melding a Portolan to the Ptolemaic Oikoumene.

10 A4 pages and 15 A4 diagrams.

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1370 1372


Many researchers have commented upon the length of the Mediterranean Sea as determined by Marinus and Ptolemy at 62 degrees from the Pillars to Issus. They have hypothesized upon the reason for that expansion from the geographical 41.483 degrees and the latest paper is no exception. Published in CaJ 53 No1, February 2016, it merely uses the same mathematical techniques as others have, such as the 2013 paper in Memocs to which it bears a striking resemblance, but does not in fact explain how the 62 degree length was determined. This paper uses the simplicity of cartographical draughtsmanship for an examination of the actuality of the Mediterranean Sea profile to determine the facts and thus indicate the original concept for the length as given.

The text is 10 A4 pages and has 10 A4 diagrams.

October 2016
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1387 1393


All latitudinal measures can only be determined on the face of the Earth and thus any given measurement can be assessed as to its place of origin, because the earth is an oblate spheroid, a fact not known in antiquity, and thus has variable latitudinal lengths. But when the measurements used are variable but by having the same name can be completely misinterpreted, any attempt to ascertain its actuality whilst not doomed to failure can end up being mathematical, “playing with numbers”. Thus a strict evaluation of the parameters, both the form of the Earth and the base length, the Stadion, must be made to avoid the criticism of numerical fantasies. This text attempts that with regard to the latitudinal degree known as 500 stades, exploring all facets of its possible origination from ancient times.
I have appended my text ChMEA/1; Charts their latitudinal measures re-assessed from historical attempts to define the degree of latitude as it preceded this new text and is in fact therefore a text which should be read in conjunction with this text CgSTA/1.

The text is 7+7, A4 pages and contains 6, A4 diagrams..

November 2016
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1403 1407


Now comprising 10 sheets; the ‘Raxon de Marteloio’, ‘seven charts’, a ‘circular World map’ and a ‘Ptolemaic world map’, they have now been removed from a binding which stitched through their centre fold and presented in a boxed edition folio. It was produced in 1993 as a special publication of 1500 exemplars, (this authors is number 1148), and has a text by Professor Piero Falchetta of the Biblioteca Marciana,Venice, which holds the ‘Atlante Nautico’ and he describes the content (in Italian) but does not attempt to analyze the diagrams or charts cartographically. It is a historian’s narrow view of the ‘Atlante Nautico’.

This paper delves into the construction and draughtsmanship required for the charts, their geometry and trigonometry as well as explaining the ‘Raxon de Marteloio’ principles as set down by Andreas Biancho which have hitherto been basically mis-represented and not forensically examined to exhibit the simple facts. There is also a discussion apropos the supposed Ptolemaic map of possibly indifferent authorship and the problems there-of.

14 A4 pages and 29 full colour diagram maps

February 2014
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1475 1478


The charts within ‘Atlante Nautico, 1436 ’, are all drawn upon the same size parchment, 260 x 380mm, which in all probability was produced as sheets measuring 262 x 393mm, 1 x 1 ½ Palmo and hence the measurement system of the charts can be assessed. The wind rose is constant upon each chart at 240mm which is thus 11 uncia, (the 262mm is 12 uncia, 1 Palmo). However the chart scales differ, but, they can all be shown to be drawn by the same hand, that of Andreas Biancho. However the last sheet, the Ptolemaic World map, although included in ‘Atlante Nautico’ may not be by Andreas Biancho, and thus its very individual form, its non-alignment to other similar maps is questioned.

9 A4 pages and 11 full colour diagram maps

February 2014
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1494 1497

PORTOLAN CHARTS: CONSTRUCTION AND COPYING [Occam’s Razor Methodology (Lex parsimoniae)]

The subject of the Portolan chart is fraught with difficulty, particularly how were they constructed. This text is the description of a forensic examination of the Jorge de Aguiar Portolan (1492) by redrawing, line by line, from basic principles. Used here-in are also many texts to illustrate preceding research. The conclusion is that they were very simply drawn using a graticule, not generally a circle, and a template or pattern was utilized to draw the map itself.

Note, this paper in a basic form was sent for referee’s comments which are included here-in.

Key words: Geographical map; Magnetic basis; Graticule; Template; Utilization of Chart; Portolan or Portolano Chart.

16 A4 pages and 11 full colour diagram maps

February 2014
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1540 1542


The portolan’s of Angelino Dulcert and Jorge de Aguiar are again examined but this time to establish the minutiae of the maps draughtsmanship, as opposed to the preceding text, “Portolan Charts; Construction and Copying”, [ref. ChPo/1] which examined how the whole Portolan could have been drawn. The method of examination chosen is by a redrawing exercise as opposed to a cartometric programme. A paucity of node points and the tendency to produce curved lines which are not part of the Portolan repertoire are the basic reason for the non utilisation. This paucity leaves large areas of sea and tracts of land behind the littoral subject to an averaging of the distortion grids and a tendency therefore to perceive the plot as correct, when in fact it is not.

Thus from an initial visual appraisal of the map to a detailed point by point recognition of the maps form, how they were first conceived and then drawn, the process becomes apparent.

13 A4 pages and 14 full colour diagram maps

February 2014
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1545 1547


Although research into the Portolan Chart genre has been extensive, it appears not one researcher has actually tried to draw a Portolan Chart from first principles. This fact is bemoaned by many persons who consider themselves expert in the field, have written extensively about these charts, but have never drawn a chart or tried to copy one. It is therefore pertinent to ask if the research is all it should be. Why has it not happened?

This text follows the process of a chart from its very basis, the vellum or parchment upon which it is drawn, to the draughtsmanship of the chart and finally how it could be successfully copied without the process being visible upon either the master copy or the second copy. Many texts are used in the analysis and found to be wanting.

22 A4 pages and 17 full colour diagram maps

August 2014
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1550 1552


The text by R J Pujades i Bataller referring to the winds and technical items within Les Cartes Portolanes is contained within pages 473-481 and 513-514. Here-in R J Pujades sets down his research and reasoning for the origination of the physical work entailed in producing a Portolan chart, the process of copying and the possible scales used as a reason for the charts observed sizes. He clearly focuses upon the wind diagrams and its draughtsmanship, but, it can be clearly shown that his reasoning is based upon a false premise. The background graticule can be shown to be the arbiter of the Portolan chart with the copying method to obtain a number of similar charts merely the use of templates. The background graticule assists in the primary positioning of the map, and certainly provides the chart scale.

20 A4 pages and 20 full colour diagram maps

November 2014
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1594 1596

FOUR MARTELOIO SAILING DIRECTIONS 1295/1436AD; Ramon Lull; Michael of Rhodes; Andreas Biancho & ????

When the Portolan chart was developed in the 13th century, it was covered by a myriad of lines to represent wind directions. These were to assist mariners to gauge the sailing direction from port to destination and also correct their course when adverse winds affected the sailing direction. However, as it was then mainly coastal sailing and not open sea crossings the usefulness of the myriad of lines is questioned .
But, distances sailed could be taken from a chart, (the scales were so very small and thus inaccurate), or read from the more accurate Portolano, a list of ports, inter-distances and obstacles to be avoided. As the distances became greater and more routes were across open seas, not coasting, accuracy in the direction sailed and distances covered became necessary. The magnetic compass was one tool giving direction, but its accuracy was poor and possibly not understood, and distance had to be measured by empirical means; inaccurate!
Hence it became necessary to record actual distances sailed such that when adverse winds affected the course, distances off course and then the return course and distance could be calculated. The return course was generally a logical extrapolation from the wind rose; that is if the ship was blown one quarter wind south of the intended course, the return course would be one quarter wind to the north with equal sailing distances involved. But if the off course sailing was the resultant of many tacks it was necessary to know how far had you sailed, how far off course you were and how far you must sail on a return course to find your original course, and that required calculating; an arduous task with doubtful accuracy.
Thus the Marteloio was developed and improved perhaps by usage. What usage it had is unquantifiable as it does not appear in the texts or notes of many mariners. And we must also note that most sailing was done along shorelines not across open sea for hundreds of miles as the Marteloio accommodates. Thus a degree of scepticism is required of Marteloio.
There are four sections to the text covering differing Marteloio papers with new diagrams.

38 A4 pages and 16 full colour diagram maps

Novmber 2014
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1623 1626


The 1403AD Portolan Chart of Francesco Beccari has been studied in a historical and a technical paper. Commented upon as unique for its latitudinal scale and what may be considered a rather self serving, apologetic text for past chart failures, it requires researching.
Ignoring the previous texts for the main analysis of the 1403AD chart, the actual evidence paints a different picture. Thus it is then possible to show by comparison to those texts the technical detail that should have been assessed and thus a more correct conclusion arrived at.
Finally, the 1435AD Portolan Chart of Battista Beccari is also analysed with the obvious necessity of a comparison to the 1403AD Portolan Chart.

12 A4 pages and 20 full colour diagram maps

February 2015
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1650 1652


Within the pages of Les Cartes Portolanes, R J Pujades argues that the background graticule of the Portolan charts, although drawn on each chart, is not ipso facto part of the construction. On page 513/514 entitled “The Keys to success; the wind network and the decimal based scale”, he concludes,

“Does this mean that the wind network played no role in the actual construction of the first graphic designs reproduced in nautical charts? I do not believe so, since it is one thing to deny the usefulness of the wind network as a basic pattern for obtaining new copies from a previously established model, but quite another to extend this conclusion to the initial moments of the configuration of the first models”.

This is shown to be based upon a false premise, from non-researched extant data which is adequately shown upon the Portolan Charts themselves as this text will indicate.

12 A4 pages and 14 full colour diagram maps

March 2015
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1674 1676

Simplicity: Drawing a Wind Rose Graticule Utilize just one measurement and straight lines

The wind rose graticule has been shown to be a simple geometric construct based upon the side length ratios of a triangle for angular deviation. The ratio of the squares when drawn is 35: 30: 20: 7 TRU’s (trignometrical ratio units). But what if the charts size and chosen scale does not allow for an easy conversion of the ratio numbers to scale measures? This text is an appendix for the original ChWr/1; Wind Rose Construction text.

March 2015
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The earliest Portolan Charts numbered C1 to C4 in “Les Cartes Portolanes” and the Lucca Chart are compared to each other and a Geographical Mercator chart. Thus the similarities of draughtsmanship can be observed and as only one set of Portolan Charts by P Vesconte (C3+Atlas) are signed the opportunity of possibly attributing anonymous charts becomes viable as the outlines coincide, in one instance spectacularly.

9 A4 pages and 26 (33)full colour diagram maps

May 2015
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1719 1721


The conclusion to my text ChCs/1 is that the Riccardiana ms 3827 chart was in all probability an original Pietro Vesconte Chart and dated from 1300/1310AD. Via my draughtsmanship/cartographical evaluation it was shown to be the template for the later charts and atlas of Pietro Vesconte. Now continuing the comparative study with five more charts as noted below, the Riccardiana ms 3827 chart would appear to be the template, or its copy or predecessor, the template for other known and unattributed charts of the period. There are minor deviations in the construction of charts discussed and perhaps following this evaluation a re-ordering of some in the L.C.P. sequencing may be found necessary.

There are 7 A4 text pages and 18 (32) A4 diagrams

June 2015
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1781 1783


The atelier of Cresques Abraham (1325-1387) was undoubtedly a continuation of the atelier of Angelino Dulceto (!name!), who probably arrived in Majorca late 1320’s, having learnt his cartographic trade in Genoa. He was possibly still producing charts in the early 1340’s, as Chart C9 (London, Add.MS 25691) is dated to that period, although some scholars consider it may precede the 1325, C7 Chart. My ChCs/2 text also details this point as a possibility. However the change of date does not preclude the atelier continuing to the 1340’s and being the Cresque base, as the Cresque Chart is undoubtedly a copy of the Dulceto (!) charts. Therefore it is possible to opine that there is a linkage between the two ateliers.
The Cresques chart does however have two unusual features drawn thereon, one is quite unique, the second a copy feature, which are discussed in detail within this text analysis of the chart. It is then compared to the Dulceto (!) charts and other charts following the system developed for the ChCs/1 and ChCs/2 texts.

The text is 7 A4 pages and 11 (16) A4 diagrams.

June 2015
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1802 1804


The Portolan Charts that are available for testing as practical navigation aids are mostly highly decorated “library” charts, which although a visual feast are so complicated in their presentation as to be unsuitable for use in a dark cabin or ships open cockpit. It has been surmised by various authors1 that those used (if they were) on board ship were the same charts but with none of the decoration to obscure the main navigation elements. But are these charts actually an aid in any presentation mode, or are they an encumbrance through the methodology required to use them on board ship. But, were they actually used on board ship?

This text analyses the simple route from Majorca to Alexandria, Egypt, using two sailing methods; that of the Portolan chart via the magnetic compass and that using the geographical wind directions and natural phenomena, the Sun and Stars for guidance. The research cannot attempt to emulate every minor course change that was necessary and must therefore be a simple discussion that considers all methods equal and that deviations on each course will cancel each other out. There is no methodology or patent formula to allow for quirks in the sailing methods of the medieval sailors given that at various times of the year the route will require a different form of sailing for the winds and tidal flow in the Mediterranean Sea. Thus for this text, the wind is constant with no tidal deviation. However one constant used is the magnetic deviation for the period of 1300AD for the whole Mediterranean Sea, 5 degrees east to 16 degrees east declination.

There are 18, A4 pages and 11, A4 Diagrams for this text.

September 2015
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1818 1820


The accuracy of Portolan charts has been shown in my previous texts, ChCs/1 and ChCs/2 where I have compared them to each other and a geographical Mercator map.
But in 1987 J T Lanman wrote “On the origin of Portolan Charts” and within chapter 8, “A proposal for the origin of Portolan charts” he wrote 6 sections (large paragraphs) and a concluding paragraph. The 6 sections are Data Base, Projection, Skewing, Purpose, Distortion and Contemporary evidence.
This text illustrates that J T Lanman was misguided in his theoretical approach, when he concluded that an accurate chart could be drawn from the data within the coastal section of the text, “Lo Conpasso de Navegare”, when it patently cannot. He also concluded there was a magnetic declination used to plot the coastal courses within the text. Then he used a square grid for his reconstruction which has been shown to be nonsensical. The graticule is rectangular and although it appears to accord to a Mercator map, that is coincidental.
That his points are spurious is amply illustrated in this analytical text. It is necessary to point out though that J T Lanman used a text with many errors for the distances and bearings, and appears not to have cross checked the distances from the Peleio route distances which are multitudinous within the text and generally very accurate.
Thus I am able to add a postscript to this analytical text which has a surprising conclusion concerning the actual possibility of drawing a map from “Lo Conpasso De Navegare”. But it is nothing to do with J T Lanman’s theoretical charts.
This text is a précis of my complete analysis of “Lo Conpasso De Navegare” carried out to investigate the possible uses for the text and its accuracy. It concentrates only on the Western Mediterranean Sea area from the Pillars to Sicily, as a means of curtailing the text.

There are 23, A4 pages and 10, A4 diagrams.

September 2015
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1824 1826


The Carta Pisane has been the subject of much speculation since it surfaced in Pisa. Is it the oldest known example of the genre of Portolan Charts, the dating is rather nebulous: was it drawn using the text of “Lo Conpasso De Navegare” (LCN): was it used at sea, thus its deleterious state: why does it appear to exhibit far more than the supposed next set of charts by Pietro Vesconte: is it merely a wishful thinking plot and not reality in the extreme areas of the chart. All of these points have been discussed ad infinitum by researchers, but the actual chart I believe has never been the subject of a forensic cartographical examination until now.
The only definite from the above list that can be quantified concerns “Lo Conpasso De Navegare” and that has been shown to be unlikely as the source of the chart using the “Starea” descriptions alone. This paper concentrates on the technical cartographical aspects of the chart, its scale, draughtsmanship and the methodology that was probably used to construct the basic outlines, but at all times uses the LCN as the basic parameter. Whether that is a correct assumption may be argued, but at least it is a basis for evidential research. The Peleio distances are shown to be the primary source of distance measure for the chart with their wind directional component. It is then shown that the actual coastline between node points gained from the Peleio distances is freehand drawn, mostly guessed, but some with real knowledge of the shape and form of the littoral.
The two wind roses are shown to be dimensioned using the same mathematics as the “Tavola De Marteloio” for the 45 degree alignment, that is 71 units, and thus the overpowering square features located in four positions on the chart are quantified.
There are correspondences and also complete differences to “Lo Conpasso De Navegare”, and thus that text does not provide for an adequate guide to the charts origins. But, the Carta Pisane is a carefully constructed chart suffering from the vagaries of poor and corrupt data producing distortion, not magnetic declination, and neither does it produce a chart usable for Pelagic Sailing because of the distortions there-in.
It is however in part well drawn and requires visual assessment over and above the first impression it unfortunately portrays by its state of preservation.

The text is 16 A4 pages and contains 25 + 2 A4 diagrams.

September 2015
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1855 1863



Having analysed “Lo Conpasso de Navegare” “Grazia Pauli” and “Liber de Existencia Riveriarum” texts to produce my text ChLCN/1, and then compared it to “The Carta Pisane” in text ChCpS/1, I concluded that the LCN text in its “Starea” section was unfit for purpose as the basis for constructing a chart. However, the Peleio section of LCN could be the basic data with which to draw a map or chart from the matrix that could be produced there-from. Although Peleio distances correctly positioned a large number of coastal features they required evaluating to determine if they were the actual basis of the Portolan Chart construction. But of course the LCN does not include the Atlantic Sea area!
Starting with the Peleio distance/directions, all +300 of them plotted on a series of maps, I concluded that a triangle formed the basic reason for the choice of node points. The points interlinked to cross locate from many of the coastal features. In fact a considerable number of the individual Peleio distance/direction notations were very accurate such that there could be NO magnetic deviation within the text details.
There were however many obvious scribal errors both for distance and direction when evaluated against a geographical map. Most could be shown to be attributable to poor copying, scribal error, but one section is solely responsible for the apparent distortion of the charts, which has led to the belief in a magnetic deviation.
My conclusions are that an original form of LCN Peleio data was used to draw the Portolan Charts. I believe the origin is probably from the Roman Period 300BCE to 300CE: there is no magnetic deviation at all in the charts draughtsmanship: the inaccuracy of the map plot is attributable to the mistaken distance measures from Sardinia to N Africa which imparted a bias in the map plot: the measurement used on the early charts is derived from the Roman Mile of 1.47911KM as one chart actually indicates.
This text cannot itemize every single Peleio; the majority are on the diagrams within this text and in the two previous texts, but where it becomes impossible to read alignments due to the sheer complexity of lines I have chosen for clarity of presentation to use a minimal number of Peleio triangle distances and thus simple Distance/Directional information.
I am sure interested parties will be pleased to draw the data for themselves and submit results. I also suggest the diagrams are downloaded, printed and joined to form large single maps (they are marked for that purpose) which will explain the twist and its false representation as a magnetic bent. It will also show that the simplest of presentations which have been misread as possible projections are nothing more than the result of drawing from a central alignment both east and west. Thus the natural positioning of a node point from the triangles causes the supposed projection. I repeat, there is no magnetic deviation on a Portolan chart!!

This text is 16 A4 pages and 29A4 diagrams. (29 pages as presented)

November 2015
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ChCPC1 Images

ChCPC1/D01 ChCPC1/D02 ChCPC1/D03 ChCPC1/D04 ChCPC1/D05 ChCPC1/D06 ChCPC1/D07 ChCPC1/D08 ChCPC1/D09 ChCPC1/D10 ChCPC1/D11 ChCPC1/D12 ChCPC1/D13 ChCPC1/D14 ChCPC1/D15 ChCPC1/D16 ChCPC1/D17 ChCPC1/D18 ChCPC1/D19 ChCPC1/D20 ChCPC1/D21 ChCPC1/D22 ChCPC1/D23 ChCPC1/D24 ChCPC1/D25 ChCPC1/D26 ChCPC1/D27 ChCPC1/D28 ChCPC1/D29

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I have already subjected the Starea section of “Lo Conpasso de Navegare” to a detailed examination in text ChLCN/1, and followed it with a research paper concerning the Carte Pisane, text ChCPS/1, and then a major investigation of the Peleio section of LCN which illustrated in text ChCPC/1 how the basic forma for a chart could be constructed from the Peleio data and negated the idea of any magnetic interference in the charts construction.
This text uses three more charts, Cortona, Vesconte 1311 and Dulceto 1330 to investigate the continuation of the usage of an “LCN” text and compares the results to the Riccardiana MS3827 chart used as a reference point in the ChCPC/1 text.
The findings are that all use a version of the “LCN” text as the distance measures clearly indicate, but their draughtsmen or cartographers are somewhat different in their approach to the extant data c1300AD, which indicates several varying content copies of “LCN” then extant.
The Cortona chart is surprisingly accurate; it has hidden attributes. The Vesconte 1311 chart, although only of the eastern Mediterranean Sea basin is shown generally to accord with the “LCN” data, but it has been drawn from the east and thus shows a greater distortion derived from the spurious “LCN” data. The Dulceto 1330 chart appears to apply original “LCN” data for its construction and is the closest to it, hinting at a loss of early knowledge and thus the errors in “LCN” and a copyist approach to it.
The conclusions are as already posited in previous texts; the use of one or more copies of “LCN”; no magnetic deviation; obvious access to far greater detailed data than is now extant.
Included is the text ChEPC/1, an essay regarding the timescale for the original chart.

The text is 14, A4 pages and there are 27, A4 diagrams.

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1942 1946


Within previous texts, ChLCN/1, ChCPC/1 and ChMAT/1 it has been shown that scribal errors within the LCN texts in the area south of Sardinia led draughtsmen constructing Portolan Charts inadvertently to slew to the northeast the eastern section of the Mediterranean Sea. I have already utilized charts C2, Cortona; C3, Vesconte 1311; C7, Dulceto 1330 and C8, Riccardiana ms3827 within text ChMAT/1 and thus in this text utilize 10 further charts solely for their drawn area south of Sardinia to compare their usage of an LCN text. The dates vary from 1339 to 1464 and are from C9 to C65 in LCP.
The Starea Peleio abstracted from LCN numbers 73 routes of over 100 millara and is used to cross-locate ports in both the western and eastern Mediterranean Sea. The 10 charts are presented with their scale bars to illustrate the variation but mainly the continued use of an LCN text. Thus the slewing of each chart can be shown via the distance measures used, which vary as is discussed briefly for each chart, but, the obvious agreement between them indicates that the information they are drawn from is the same “Alpha Map” base, and “Alpha LCN” text, which has been mis-copied in certain sections.
In my short essay text ChEPC/1, I opined that the Peleio section of LCN was probably taken from the “Alpha Map” as they are impractical to observe as sailing direction/distance measures at sea. I then constructed a scenario, purely speculative, which indicated that the original Portolan Chart was much earlier than 1000AD and developed from a Roman Map and itinerary text. The theme of the maps usage and ancestry is continued in this text regarding the possibility of the Starea Peleio section being driven by the necessity, firstly of the routes to be used by the new maritime cities, and then of sailing for the Crusades which provided an impetus to increase, diversify and rename ports to suit the new age and the explosion in sailing. But many quirks are included on these charts to fool us.
Thus having completed a review of LCN and the major charts of LCP, C1 to C64 and confirmed the obvious fact that by using LCN Peleio distance directions, which all charts can be shown to agree with, there is no magnetic deviation involved, just the slewing caused by the miscopying of the LCN data, Roman Numerals for south of Sardinia, it became necessary to subject the two texts used by many researchers as the basis of the Portolan Chart storyline. I refer to firstly HOC/1/chapter19 text, particularly pages 380 to 386 which deal with the subject matter of my papers and then LCP (English section) pages 510 and 511(part) which are the similar subject matter. Pages 511 & 512 are dealt with in a following text, ChCOR/1.

The text is 18, A4 pages and contains 20, A4 diagrams.

February 2016
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1971 1974


The Cortona Chart is often linked with the Carta Pisane (LCP, C1) because of the perceived similarity of presentation, its draughtsmanship and the coastlines. In my text ChCPS/1, The Carta Pisane, I fully analysed that chart’s construction and its basic internal knowledge. This text analyses the Cortona Chart in a similar manner and juxtaposes “LCP” pages 511/512 text with my findings. The resultant research illustrates that there were a multitude of “LCN” type texts used throughout the first period of the “Library Style” Portolan Charts, following the end of what must have been a massive flotilla of ships virtually constantly at sea to service the Crusades and trade that went with them, but no doubt using smaller and easily handled maps and complementary texts, Portolani + Chart.
This text starts with the Black Sea area on the chart, discusses the separate scale utilised and then the textual data available which is not apparent upon the chart. A section of the text has already been published in ChMAT/1, and is here-in appended, un- revised but very necessary to complete the research which follows the prime discussion of the Black Sea area. I have also indicated the “distortion” positions within the chart which not only make it accurate in a serendipitous manner, but show its construction from an “LCN” text. Finally, the reason for the charts distortion is revealed, simple distance measure errors which combined to visually confuse previous researchers into thinking there was a magnetic element; there is not. But why the draughtsman chose to use two differing scale bars can be answered only speculatively. As an extra discussion the Black Sea is investigated in a short essay reference ChBLS/1. The same change of scale on other charts and atlases and the actual form that can be obtained from the” LCN” text is drawn, which confirms the fact that a “Alpha Chart” was available and several “LCN” texts of varying quality.
Draughtsmanship before history and you will solve a great deal more far easier!

The text is 13, A4 pages and 8 + 6 + 10, A4 diagrams (24 in total from 3 sections of text).

March 2016
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2005 2007


Many researchers have written texts which in part discuss the work of A. Dulceto, and imply the finding of magnetic declination, magnetic compass usage to plot the charts and differing projections used to draw them.
I have chosen therefore the same chart, A. Dulceto 1339 (LCP C8) held by the BNF Paris as the base data with which to counter those theories existing in the four texts to be analysed. The chart is first dissected to indicate its fundamental structure and the varying scales used from west to east, Ptolemaic Degrees, Millara, Roman Miles and Marritimo Miglio, as well as the reasons for its skewing. The link from Rome via Claudius Ptolemy to the Millara is clearly shown and thus the origins of the “Portolani” and its accompanying chart are confirmed. Any researcher who has read my previous papers will not be surprised at the findings, quite incontrovertible, as they are merely the data the chart exudes, and thus will understand why I have not written reams of text in explanation of my findings for this 1339 chart. But the intervention of the Ptolemaic degree is surprising and is resolved by the explanation of the various distance measures within a Portolan chart.
Please note that prior to the analysis of the four texts, I have inserted a short but very necessary note regarding the use of Cartometry, Formulae and Computers to analyse a Portolan Chart and thus end up with bland averaging and an incorrect analysis of the chart.
The four texts are, J A Gaspar, ePerimetron, 2008; W R Tobler, Am Geog Soc, 1966 and 2007; J E Kelley jr. Cartographica, 1995; and C Boutoura, ePerimetron, 2006.
The results of this critique are expressed quite directly and thus I would advise caution when future researchers may wish to utilize them; I consider them to be lacking.
NOTE: I am still awaiting a researcher to explain how the magnetic compass was used to plot the courses and then, how the pilot book data led to a Portolan Chart to be drawn. It has been stated again in 2015 that “owing to the navigational methods of the time, which were based on magnetic directions and estimated distances”, that research is so very necessary. Why the “Pilot Books” extant do not use magnetic data requires answering.

The text is 22, A4 pages and contains 23, A4 diagrams.

April 2016
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2035 2040


The chart is obviously an excellent example of the genre, but it is also obviously an amalgam of two schools; Claudius Ptolemy and a LC de N derived Portolan Chart. The western section from Britannia southwards through France, Iberia to N. Africa is drawn to the Ptolemaic dictum as expressed in the prologue to Book 2 of “Geographia”, a simple proportion and rectangular graticule. But this only applies from 9W to 3E where the L C de N format then becomes apparent and the usual errors around 9E longitude skew the chart to fool some researchers into the magnetic declination school of thought. However the main problem can be observed at Bugea (Bejaia) on the N. African coast where the distortion is so apparent.
The eastern Mediterranean Sea is drawn quite accurately but expanded to agree with the L C de N Black Sea over length such that the chart is in proportion at this point.
The chart is an exceptionally well presented Portolan Chart which indicates a growing knowledge of the mathematics involved and the greater accuracy of measurement. Thus the cartographical draughtsman can experiment with the latest (although 100 years earlier) ideas as promulgated by Claudius Ptolemy in the then translated “Geographia.” But it should be borne in mind that the whole genre of Portolan Charts has always in its background had the Roman measurements and Ptolemaic proportion within the makeup of the chart. However, still after +200 years it is evident that the “Portolani” texts are obviously still being used.
Unfortunately, the Butterfly did flap its wings to cause enough Chaos in the finished chart to be noticeable, which is actually a sad occurrence for a thing of some beauty.
I have chosen to juxtapose this chart with a short text regarding two charts, Jorge de Aguiar, 1492, and Pedro Reinal, 1504, which show the partial development of the Iberian Peninsula as a rectangular graticule. The Pedro Reinal chart has the fully formed latitude scale in a similar position to the Jacobus Russus chart and thus they can be compared. This text was originally indexed as ChMES/1 and has 7, A4 pages and 6, A4 diagrams.
This text contains 6, A4 pages and 16, A4 diagrams which all interlink in their series.

Totally the text is 13 A4 pages and there are 22 A4 diagrams.

May 2016
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2067 2070

PORTOLAN CHARTS OF 1413, 1436, 1448 & 1463/9; THEN CAPE VERT AND 3 LETTERS FROM 1495


The exploration of West Africa from the Strait of Gibraltar to the Gulf of Guinea is a story of two or three parts. Firstly we have the recorded voyages pre our common era, and then apparently nothing south of the Canary isles until the Portuguese explorers ventured forth in the 15th century. Thus the second part may be described as the scramble by Portugal and Spain to land grab as much as possible. This caused friction between the two nations and was eventually solved (!) with the agreement reached at Tordesillas in 1494 (among others) and thus we have the letters of 1495 endeavouring to explain it all cartographically.
But all of that ignores the large Arab presence, their knowledge of the coastline and the fact that it was transmitted to N. Africa and thus the Iberian Peninsula in the 10th to 13th centuries. Finding the information however has proven nearly impossible, hence the following methodology, as even the text of Al-Idrisi shines little light on the knowledge. Thus this text uses the Portolan charts/atlases as a means of illustrating the knowledge gained in by the late 14th and early 15th centuries, how it affected the presentation of the knowledge and the gradual correcting of the spurious data which so affected them.
Obviously, between the 1413 and 1436 charts the work of Claudius Ptolemy intervened and affected presentation. The letters of 1495 illustrate the confusion reigning at the time over distance measures from the ancient metrologies, and the utter disregard various countries had for each other’s measurements, even though a single measure was available. This text therefore also tackles the vexed question of the confusion between the Millara and the Roman Mile and presents a reasoned argument for the Millara origination, no not 5/6ths.

The text is 21, A4 pages and contains 26, A4 diagrams and 4 appendix pages.

February 2017
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The Petrus Vesconte 1311 chart has featured in several previous texts, but has never been subject to a complete internal structure evaluation. This text merely corrects that omission and illustrates the accuracy which can be found longitudinally and the obvious latitudinal faults which appear to follow through to most extant Portolan Charts of later date. Those faults are distortions and are clearly set out in various papers but will be detailed here-in to define the charts. The wind rose system is the setting out and has been adequately shown to be the arbiter of the plot via its measurements. The atlases, concentrating on the 1313 and 1318 work indicate conclusively that the typical distortion of a Portolan Chart, basically shown as being from Iberia to Italy, could have been avoided by the correct application of distance measures for Iberia and from Genoa to N. Africa and a full understanding of the measurement of a degree which varies even though the name of the unit is the same. But the problem of the scale bar being firstly a Roman Mile and then considered a Miliaria can be shown to be the main cause of the deviation of the latitudinal and longitudinal lines to enthuse historians to conclude that the distortion was a magnetic deflection, Just how wrong they could be is illustrated here-in. Various other small charts are illustrated for continuity of the works by Petrus Vesconte.
There is finally an appendix which illustrates the whole distortion scenario, how it occurred and the consequences for Portolan Charts, with after words that require to be said!

The text is 15 A4 pages and has 28 A4 diagrams.

August 2017
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Having studied a large number of Portolan charts, as the website clearly shows, I was struck by the lack of examination of extant Atlases in the research texts of others. Those Atlases are detailed in Les Cartes Portolanes, pages 69/70, and having just reviewed my research into the work of Petrus Vesconte (ChPV/1) and revisited his Atlases, I decided to review my research including those Atlases and others, not all of them, just the first 14.
However, I did not consider that a short text could contain a complete review of those chosen as I had carried out on the Petrus Vesconte 1313 and 1318 Atlases, but instead concentrated upon the Atlas page containing the Iberian Peninsula, the starting point for the utter confusion which can be shown to exist apropos distance measures and thus the original distortion point for Portolan charts.
As there is generally only one scale bar to each Atlas page, it is thus a simple matter to ascertain the accuracy and measures utilized to draw each sheet. Thus, when a confusion of distance measures is encountered on this one Atlas Page, emanating from a single scale bar, little more than those facts require to be investigated. It also determined that the draughtsmen were not au fait with their subject matter and thus should be considered only copy artist’s, but from what? That does not infer criticism of the artistry to produce these Atlases as they are a feast for the eyes, and illustrate exquisite draughtsmanship but a lack of real knowledge, and confirms they are copies, not original works. How many originals were copied is detailed.

The text is 11, A4 pages and contains 16, A4 diagrams (some are text based).

September 2017
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2142 2144


Having analysed the Atlases LCP A1 to A14, concerning the Iberian Peninsula and established that there was a complete lack of knowledge apropos the actual distance measures utilised and that the unit of measures were also confused, it was necessary to proceed along the time line for Atlas Charts to further our information concerning their inner workings and establish if the problems encountered were in fact solved.
Hence as the BNF Paris had excellent scans of the Atlases by Diogo Homen and that fortuitously they had featured in my first Portolan Book from Thames and Hudson, I knew they would shed light upon the subject. Thus a complete analysis of two beautifully drawn Atlases by Diogo Homen was undertaken, as well as an analysis of one of his excellently drawn Portolan charts, to establish the extra knowledge gained over the ensuing +100 years from 1434 to 1559AD. Unfortunately the results were very disappointing and add little to the original data which has been compiled as the problems persisted with no new knowledge.

The text consists of 6, A4 pages and contains 17, A4 diagrams

October 2017
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2169 2171


Throughout previous texts I have shown that the inner workings of Portolan Charts and Atlases indicate several distorting factors which have the effect of slewing the chart anti-clockwise from c3 to c11 degrees. That difference can be evaluated as the accuracy of the charts author in his draughtsmanship. But a study of the Iberian Peninsula showed that the basic slewing was in fact c12 degrees and emanated from one single fact; the draughtsman had used two distinct measurements for a degree of latitude which are in fact the same measurement in different forms but had used a single scale bar to measure them, thus totally ruining any accuracy that may have been possible. Therefore the Iberian Peninsula has the in-built potential to totally slew the whole chart by c12 degrees.
But that appeared to be a rather curious situation akin to the tail wagging the dog.
Thus I considered that the problem is in fact the opposite; that is, the chart was first drawn with a 12 degree slew anti-clockwise, then the Iberian Peninsula was tacked onto the chart, which would be correct if it was, as I have suggested previously a Roman Map. As the Roman World expanded the chart grew to encompass all of their lands and thus was not necessarily at first a full Mediterranean Sea basin map, but evolved from several forms.
Marcus Vipsanius Agrippa produced a “world” map in c11BCE following a “world survey” instigated by Julius Caesar in c54BCE, and that map was displayed in Rome.
Thus using extant Roman Texts this paper sets down the scenario for the 12 degree slewing of one of the original Roman Charts and how it developed into a Portolan Chart.
I have added to this text the work by Joan Blaeu, not for his charts but for his written words which discuss many of the problems I have uncovered.

This paper contains 19, A4 pages and 17, A4 diagrams.

November 2017
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A fellow researcher kindly sent me a copy of his paper regarding the “Enigmatic Chart” by Baldassare (Maiolo) Maggiolo, dated 1589 which appears to be drawn as four atlas pages each rotated 90 degrees from the next thus forming a rotating vista. That original text (q.v.) is predicated upon pixel measurements which to my draughtsman skills implies accuracy far in excess of that achievable in the 16th century, and does not allow for the vagaries of the charts actual drawing which was to be explored. My interest was thus piqued and I decided to explore the charts inner working and format which was made even more fascinating as the original text included a thumbnail copy of the Munich chart from Sir Robert Dudley’s Dell’Arcano del Mare. That original text stated “une carte tres similiare”, but then ignored it.
Thus there are two “enigmatic charts” which together may answer the question regarding their extraordinary presentation I therefore explore both, and with their idiosyncrasies endeavour to explain their raison d’être. The original text, chart and Munich chart are appendix notes.

This text contains 9, A4 pages and also 30, A4 diagrams.

December 2017
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2191 2193


The text is in two distinct sections; firstly an analysis of the chart dated 1500 noted as being by Juan de La Cosa to understand how it was drawn, the measurements used and the probable origination of the data used; and secondly an analysis of the “raw” historical data regarding the “La Cosa” personage and his exploits after stripping out the hyperbole and extravagant overstatements of many authors who have written concerning the whole subject of the exploration of the West Indies.
Both sections are written as stand-alone texts and need not be read as one paper.
This section casts doubt upon the authorship of the Chart and perhaps the date appended, as it appears to have information that was only known after the 1500 date and is thus thought to be 1502 at the earliest as others have suggested, but in fact could be even later. This section also questions the charts origination. The second section is merely the historical facts that can actually be accepted as such. But, as only confirmed fact should be used before accepting circumstantial evidence, and there being little definitive data to go on, speculative texts abound and they must be challenged. Both sections have their own Abstract/Introduction and they are not cross referenced to each other to allow the reader to reach his or her own conclusions from the evidence presented.

The part one text is 13, A4 pages and contains 28 A4 diagrams. Pages 1 to 13.
The part two text is 8, A4 pages and contains 1, A4 diagram, D01 from above. Pages 14 to 21.

March 2018
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Having read many texts concerning the Columbus exploits and thus knowing of Juan de La Cosa from those texts and his c1500 chart, I was totally bemused by the chauvinistic approach of many authors and how in each text new titles appeared when the historical facts did not actually agree. It appeared to me to be a little massaging and improving the data.
Thus I decided, but against my better judgement and contrary to my normal approach of analysing charts and maps, to explore at the most basic level the history appertaining to Juan de La Cosa. As has been stated by others, there is little hard evidence (or none in reality) regarding him prior to 1492. Even where he was born, his home village has been guessed by some when it is clearly written in a ships listing, but to establish the credentials of the c1500 chart the investigation is necessary.
In the first section I analysed the chart by draughtsmanship detail and now the second part is an analysis from confirmed facts with a timeline to establish the whereabouts of and the survey work Juan de La Cosa could have carried out.
Please note that to simplify references I am giving only page numbers from “Christopher Columbus, An Encyclopaedia”, edited by Silvio A Bedini, which was originally published in two volumes in 1992, but re-issued in 1998 as a single volume which is here-in used. I have and have also read numerous other texts and find that the basic facts remain the same throughout with some “gilding the lily” regarding the situation and others stretching facts to breaking point; one is enough!

The part two text is 8, A4 pages and contains 1, A4 diagram, D01 from above. Pages 14 to 21.

March 2018
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2226 2281 2305 2348 2369


The Planisphere copy has garnered many plaudits from the historical and cartographical communities for its sumptuous presentation and scope of its geography. Many historians and cartographers have written treatises concerning its contents and endeavoured to illustrate that which it portrays through technical means.
Each and every one of these researchers has completely missed the most obvious and determining part of the design by generally adhering to preconceived ideas, instead of detailed analysis of the actual chart and its construction.
This text shows that the original Portuguese cartographer was a master artist and mathematician/geometrician who understood the necessity for constant measurement, but was thwarted by the data given which obviously consisted of a myriad of measurements named the same but wildly differing. Add to that the inability to transcribe Arab “Kamal” readings to either distance or latitude and only draw what was described thus the problems mounted.
The Planisphere copy must be investigated section by section to expose the problems the cartographer encountered, but overcame, to produce this feast for the eyes.
One question I fear will never be properly answered however is, “just how accurate is the copy we are now studying”? Personally I suspect that it is not copied, but the work of the original atelier, or persons of the original atelier and thus it is probably very accurate and the distance measures originally used are perfect, as the wind rose graticule which is so very accurately constructed illustrates.
Being produced by the original cartographic atelier, or those cartographers, it would explain other problems encountered in the research. That idea is very plausible as will be adequately indicated within the text pages.
Note; I have used my copy of the CD-ROM from Biblioteca Estense Universitaria for the Cantino research and diagrams illustrated. It was produced by Il Bulino + Y Press, 2004.

The Caverio 1505AD Planisphere has been variously quoted as being copied directly from the Cantino 1502AD, or as having very similar origins. Those are probably copies of copies of the “spare” planisphere no doubt kept by the original atelier for future charts to be drawn from. That it is a copy of a Portuguese chart is undoubted from its toponyms and content, but the chart requires to be analysed to ascertain its inner workings as they are not the same. The final analysis however must wait for the next text, ChFANO/1, which indicates that the chart is a pastiche of several charts and was probably started in Lisbon and finished in Italy.

The Cantino text is 10, A4 pages and contains 17, A4 diagrams.
The Caverio text is 6, A4 pages and contains 15, A4 diagrams. (total text 16 A4 pages)

April 2018
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INTRODUCTION; CANTINO PLANISPHERE Having analysed the 1500AD La Cosa chart, the first to indicate the West Indies and South America, the next logical chart sequentially is the Cantino Planisphere, 1502AD. The historical context has been written a myriad of times, how Alberto Cantino on behalf of the Duke of Ferrara managed to purchase a copy […]

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ChFANO1 Images

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It was a finely drawn chart which even in its present state of washed out presentation has many attributes, but, obviously the chart has been reduced in size to 1395 x 910mm, and before any investigation into its actual geographical portrayal takes place there requires to be an investigation to determine to what extent it has been reduced and thus what is “missing” such that a correct appraisal of the chart can be undertaken, This has been achieved using the wind rose graticule and its setting out. This I perceive nobody has bothered about before!
Then the drawn chart is analysed and compared to other charts which numerous researcher’s state quite frequently is probably a copy of the Cantino Planisphere or its derivative but it can clearly be shown to be from a different source chart. Finally the vexed question of attribution and date is addressed from viewing the actual script on the chart.
The text is 8, A4 pages and contains 21, A4 diagrams (A3 originally).
The postscript contains 26 photographs which were supplied by Biblioteca Comunale Federiciana at FANO of parts of the chart and are an excellent aid to studying its content.

June 2018
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Being unattributed upon the parchment itself, the format has led to many researchers speculating ad infinitum regarding its draughtsman/author.
Visual inspection can be self defeating when one chart is 1140 x 1790mm and the other perhaps only half that size. In that situation the eye of the beholder can be seriously misled. Thus this text sets down the investigation of the Pesaro Planisphere into its inner workings and compares it to those other charts speculated as being similar or perhaps by the same author, but the research uses the various chart forms as the arbiter of similarity with actual overlay illustrations.
The Pesaro Planisphere is beautifully drawn, is a one off in several respects and does not appear to be by any of the speculated draughtsmen/authors; but is it finished?
Note; this paper is a diagram based paper with limited but concise text, thus the diagrams should be carefully studied to ensure the various layers are fully understood. The diagrams numbers 15 to 24 are in fact 3 charts and they can be joined together by the overlapping areas to illustrate the complete comparison of chart to chart.( A4>A3)

The text is 06 A4 pages and contains 28 A4 diagrams, all of which commenced as A3.

August 2018
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ChPES1 Images

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Henricus Martellus 1491 and Martin Waldseemuller 1507 charts both exhibit a peculiarity in the draughtsmanship design of the African Continent. Thus it appears they were both confused by a similar presentation of a plain rectilinear chart they were using to draw their curvilinear world maps or charts. The reason for the confusion is amply illustrated by the King-Hamy 1502 chart which has two Equatorial lines; one for the western geographical section and one for the eastern Ptolemaic section, but they are shown as overlapping within the African Continent.
Also to be addressed is the confusion with the nomenclature researchers have used to describe the form of these charts. They are not cordiform or Pseudo-Cordiform but plain Ptolemaic projections as can be amply illustrated. The Martellus 1489 printed charts are nothing more than an inverted Ptolemaic First Projection and then the 1491 chart and the M.Waldseemuller 1507 chart are just a slightly modified Projection Two by Ptolemy.
Thus this text commences with the Geographike Hyphegesis of Claudius Ptolemy, explores the King-Hamy 1502 chart (D01), then an analysis of the Martellus 1489 printed charts (D02) and finally the Martellus 1491 chart (D03 & D04) and the Waldseemuller 1507 chart (D05). For all of these answers are given to the questions regarding draughting methods, construction and their presentation, including their errors and foibles.

The text is 15, A4 pages and contains 59, A4 diagrams (all originally A3)

September 2018
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ChGEN1 Images

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Read research papers or books concerning Genoese 14th to 16th Century cartography and there is not one text written which investigates how it all happened and uses simple basic facts such as lifespan, training or raison d’être for the origination. The first extant work provable by attribution is that of Petrus Vesconte and his 1311 chart. But he had to be taught the art and that has never been addressed in the myriad of papers written over the last years. Add to that the Carta Pisane, probably 1290 and the Cortona Chart c1300, both of which have doubtful provenance, but by existing they push the date backwards for the training of their authors. Thus this text sets down clearly known facts and dates and uses the life spans attributable to evaluate the overlap of these cartographers and how their charts also spring from a basic pattern/template which is amply illustrated in the second part of this research.

The text is 20 A4 pages and contains 53 A4 Diagrams (originals are all A3, and some interlink to form the complete chart at large scale.)

December 2018
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Commencing with an in depth study of the actual draughtsmanship to explore the hidden features, the text then investigates the donor charts which allowed it to be drawn, much of which has been known for over 100 years, and finally shows that it is the latest manifestation of the “mappa mundi” genre which are usually drawn as circular charts.

The text is 10, A4 pages and contains 21, A4 (A3) diagrams

February 2019
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ChCATA1 Images

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This text started as an appraisal of the notes Leonardo da Vinci made upon the Geography of the World as he understood it. They were to be part of either text ChGEN/1 or its counterpart ChGME/1, but were unsuitable within either text. Thus when asked to read another text regarding Globe Gores and the link to Leonardo da Vinci, entitled “America’s Birth Certificate”, I resurrected the text for the introductory passage as it completely matched the discussion within this new text, although it showed the new text to be fallacious in much of its measurement details. It is thus a text of two parts but introduces many more research notes I had accumulated and tend to contradict the new text; but that is for others to decide as conclusive evidence is lacking on certain aspects of who did what.

The text is 16 A4 pages and contains 11 A4 (A3 original) diagrams.

June 2019
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The Portolan charts of Genoa (or Italy) commencing c1300AD through to +1500AD are all basically constructed from the same Pattern/Template as has been clearly shown in text ChGEN/1. They commenced with Petrus Vesconte and climaxed with Vesconte de Maiollo and then the Maiollo clan’s work.

But two eminent practioners of the “art of painting” charts, escaped to warmer climes and the first of them kick started what can only be described as a “golden” period for Portolan Charts and their decoration on the Island of Majorca. The second augmented the genre and ensured the origins of the Portolan Chart, basically Northern Italy/Genoa, was perpetuated by the continual usage of the original Pattern/Template for the Mediterranean Sea Basin.

Thus this text follows on from the Genoese exploration of the continued usage of a singular Pattern/Template and further explores the cross fertilisation from City to Island and around the Mediterranean Sea.

The text is 20, A4 pages and contains 58, A4 (A3 original) diagrams and 2 tables.

June 2019
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ChGME/1 Images

ChGME/1/DAA ChGME/1/DBB ChGME/1/D01 ChGME/1/D02 ChGME/1/D03 ChGME/1/D04 ChGME/1/D05 ChGME/1/D06 ChGME/1/D07 ChGME/1/D08 ChGME/1/D09 ChGME/1/D10 ChGME/1/D11 ChGME/1/D12 ChGME/1/D13 ChGME/1/D14 ChGME/1/D15 ChGME/1/D16 ChGME/1/D17 ChGME/1/D18 ChGME/1/D19 ChGME/1/D20 ChGME/1/D21 ChGME/1/D22 ChGME/1/D23 ChGME/1/D24 ChGME/1/D25 ChGME/1/D26 ChGME/1/D27 ChGME/1/D28 ChGME/1/D29 ChGME/1/D30 ChGME/1/D31 ChGME/1/D32 ChGME/1/D33 ChGME/1/D34 ChGME/1/D35 ChGME/1/D36 ChGME/1/D37 ChGME/1/D38 ChGME/1/APPD01 ChGME/1/APPD02 ChGME/1/APPD03 ChGME/1/APPD04 ChGME/1/APPD05 ChGME/1/APPD06 ChGME/1/APPD07 ChGME/1/APPD08 ChGME/1/APPD09 ChGME/1/APPD10 ChGME/1/APPD11 ChGME/1/APPD12 ChGME/1/APPD13 ChGME/1/APPD14 ChGME/1/APPD15 […]

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Searching for information regarding a Globe which I thought had dubious attestation given by J L Stevenson, Tome 2 pp47/49, regarding Petrus Plancius, I was led to the BnF Paris and a set of Gores available under their Gallica system. To my surprise I found them to be wrongly drawn and did not include the three texts quoted by Stevenson. Hence a very fast research project to find the globe ensued whilst I awaited a Portolan Chart scan to arrive.
The outcome of this research is quite surprising to say the least! And, it is merely a quick resume of the facts I have so far discerned requiring a proper research project later.

The appendix is perhaps the most surprising find, geometric errors by Mercator!

The text is 6, A4 pages and 17, A4 diagrams or photos.

July 2019
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The text “Using a Portolan at Sea, did they?” indicates quite clearly the nonsense of considering that at any time a magnetic compass was used for either route sailing or the construction of a Portolan Chart. The latest paper available, “The Maghrib’s Medieval Mariners and Sea Maps; The Muqaddimah Primary Source”, explains precisely what a “Compass” is, and it is not magnetic. Then in this text, having followed the development of Portolan Charts from their Genoese foundations in Italy, and after via Majorca and onto Egypt these two charts, one drawn in Tunis, the other certainly Arabic, but unknown are investigated. The Tunis chart is a standard Portolan, but the Maghreb chart is probably an atlas page and these are to be examined apropos the Genoese and Majorcan continuity of chart design. The indication is that the setting out of the wind rose graticule is a perfect copy of the Petrus Vesconte 1318 Atlas page which illustrates the methodology of how to draw the graticule sans circle, and these charts are typically the follow on product of Genoese charts.


August 2019
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ChAR1 Images

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The atlas dated 1511 was obviously drawn in 1510 and contains a very mixed bag of charts. They are all investigated, but the sheet numbered 08658-001 by the JCB Library, the so called Dedication page, is investigated separately as a stand-alone section text, ChAVM/2.
The atlas comprising 10 sheets was composed with several scales being utilised for the various charts. These do not at first appear to be interlinked as the atlas has obviously been re-configured in the distant past, a fact borne out by the attempts at alteration on a chart. Therefore not being as originally composed I have suggested the original order of the charts which make logical use of them as their scale bars indicate. Vesconte Maggiolo has included his version of the first projection of Claudius Ptolemy using an amalgam of old and new charts as many other cartographers of the age have. There is also a cosmography which in fact is rather redundant as a useful tool. As I surmised in my text ChGEN/1, the whole atlas required to be drawn from a complete Portolan Chart and it appears in the investigation.

The text is 6, A4 pages and contains 49, A4 (A3) diagrams.

October 2019
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A historical and technical examination of the sinister and dextra parts of the Dedication page, JCB 08658-001, illustrating the Armorials of the titular heads of Corsica on the sinister and a map of Corsica with toponyms and four elaborate monograms on the dextra. It is not a definitive work as it must be further investigated due to the complexity of the subject and a distinct lack of detailed information. Speculative in part it certainly is!

The basic facts are laid down with conclusions where possible regarding the Armorials, but the Map of Corsica and its toponyms is analysed completely and there only exist one or two curious place names that are unknown today. However in comparing this map to others it proves there are always curiosities.

There is also an appendix which discusses the cartographers in Naples c1510.

The text is 11, A4 pages and contains 25, A4 (A3) diagrams

November 2019
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Having investigated the JCB held atlas of 1511 to evaluate its geography in text ChAVM/1 and ChAVM/2, this text adds the geographical information from the 1512 atlas held in Parma and the 1519 atlas held in Munich. All three are compared to each other to establish the continuity of their construction.

Thus it is possible to opine that Vesconte Maggiolo had with him on his 1508/1509 journey from Genoa to Naples a Portolan Chart and in all probability a pattern/template with which to construct these atlas pages. They are quite accurate in their comparative state when the scale bars are aligned and they are overlaid one on the other as the diagrams clearly illustrate.

However, this text commences with Section 1 a retrospective analysis of the 1511 JCB atlas page sizes to determine how Vesconte Maggiolo actually scaled certain sheets to fit precisely to the page size of c39 x c57.6 cms. This investigation proves the use of the Roman Uncia for some of the charts construction and also that the charts are in a mathematical ratio of size with a rather extraordinary finale.

Section 2 is then the comparison of the three atlas and their inner workings and illustrates the previous findings of continuity of pattern/template.

Section 3 is a comparison of V. Maggiolo and Salvat de Pilestrina’s work which shows they are probably identical and thus from the same pattern/template drawn in Genoa.

The text is 10, A4 pages and contains 50(51), A4 (A3) diagrams, (one is a double)

December 2019
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ChAVM3 Images

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An atlas of 20 sheets plus two cosmological pages which form two complete (nearly) charts, one being a Portolan and the other a Planisphere. A peculiarity of presentation gives rise to a comparison, unfounded, to Vesconte Maggiolo 1511 Atlas, and the date must be assumed from the beginning of the cosmological information commencing January 1508. The data is presented as found including many Greek toponyms combined with Italian toponyms and also with the historical items included help conclude it is a Genoese product c1507.

The text contains 5, A4 pages and has 23, A4 (A3) Diagrams

February 2020
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A very short technical appraisal of the works by Piri Reis, debunking previous texts and scholar’s comments, dismissing wild theories via what the charts actually show, not what people wish to believe from preconceived ideas and establishing the credentials of Piri Reis as a mathematician as well as an obvious accomplished draughtsman.
The text is 6, A4 pages and contains 18, A4 (A3) diagrams.

March 2020
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There are five large similar planispheres of which two are clearly “signed” by Diego Ribeiro with the other three nearly exact copies and thus capable of being assigned and dated. This text concentrates on two examples. The first is dated 1525 on its Astrolabe diagram and by a text note, but it is one of the “unsigned” examples and held by the Biblioteca Estense Universitaria, Modena, Italy. The second is the 1529 planisphere, dated and signed and held in the Vatican Library. There are numerous texts discussing the work of Diego Ribeiro but not in a technical manner to explain the knowledge contained there-on, their foundation for design or explain the visually complicated “Declination Diagram” in a simple manner for it to be utilised.
Many other authors have implied that these five charts are in fact as near as possible to the Spanish Padron Real, the Royal Standard Map of Spain. That being the case then it is proven beyond doubt that the Diego Ribeiro Planispheres are the “mythical” Square Chart and thus the Padron Real of Spain is also a Square Chart, latitudes and longitudes are equal and there is no sign of a magnetic slewing of the Mediterranean Sea, it is geographical.
It is also possible to conclude that Diego Ribeiro was a consummate polymath and probably knew M F de Enciso in Seville when his “Geographia” was published in 1519 and certainly Ribeiro has used his text to illustrate these five planispheres.

The text is 9, A4 pages and contains 34, A4 (A3) diagrams.

June 2020
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ChDR1 Images

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Held in the Library of Congress are two charts noted as Vellum 9 and Vellum 10. They are very distressed and obviously reduced from a larger format. Dated to C1500 and C1565 because of their visual attributes they have also been noted “as seemingly sharing a common provenance and history and are therefore considered together”. However it is noted the Cartographers are possibly different; that will be dis-proven.

Vellum 10 has a “signature” which appears to have been ignored by the Library of Congress cataloguer and hence this text follows the trail found within the charts to explain their probable provenance and country of origin and the surprising mentions. It is not an orthodox paper, more a journey of discovery.

This text contains 11 A4 pages and 27 A4 (A3) diagrams.

September 2020
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The Liverpool University Chart reference LUL MS.F.4.17 is small by Portolan Chart standards as it is now only 40 x 25 ½ inches having been sadly reduced on all sides. But it is richly decorated and there is hardly a square inch of vellum untouched. However it is an anonymous chart from both cartographer date and place of drawing. Hence it requires a complete analysis to establish its provenance.

This is not a normal Portolan decorated to order but a work made to impress a client or recipient in perhaps the highest category of society. But it is clear that by studying the chart in depth for the first time the answers lay inside its draughtsmanship for all to see.

The text is 6 A4 pages and contains 21 A4 (A3) diagrams.

November 2020
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Bartolomeu Olives is the younger brother of Jaume olives and has Portolan charts to his name dating from 1538 to 1588. They are mostly drawn in Messina Sicily, but he/they commenced in Majorca and had a brief foray to Venice. This 1584 chart is held by BNF Paris, Departement of Cartes and Plans, reference CPL GE B-1133 (res), and is an extraordinary compilation. Excluding the standard toponyms it is scattered with Kings, Dukes and large writ place-names which at first sight are a strange combination.
This text analyses the chart as drawn technically and then endeavours to unravel the reasoning behind these place-names and in the process finds a 1500 year history lesson with a rather chilling raison d’être of persecution and conquest written there-on.
The text contains 12 A4 pages and 25(29) A4 (A3) diagrams

December 2020
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