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 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 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 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 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 2109


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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2142 4391


A chart and an atlas signed “ANGELUS” were supposedly drawn in Marseilles, 1571 and 1575. However viewing them immediately raises many questions as it is obviously not one persons work, unless it is spread and held for some 20 years as the earlier work is poorer than the later work. But, it may even be a case of subterfuge as it is quite likely another person’s work has been used in the atlas. This text explores that question by describing the two works in detail and comparing them to other extant works and has surprising results.

The text is 11, A4 pages and contains 28, A3 diagrams.

June 2023
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ChANG1 Images

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The earliest maps of Britannia are obviously now the lost Roman Survey maps and hence tracing the outline changes of this Island falls to what extant maps/charts we have.
However, we should bear in mind that from the Roman Invasions to the Norman Conquest of 1066AD, texts were being written which give a basic format for the island. Thus, these form part of the investigation and my previous texts will be mentioned dealing with this. My original texts are used in this text and the references are given.
But this text is merely a simple mostly visual explanation of just how much the profile changed until a more scientific approach to surveying and the coastline evaluation took place.
There are very few extant early English Maps and thus the Mediterranean Portolan Charts are part of the story line as those sailors voyaged mostly to the Hanseatic League ports.

The text is 16, A4 pages and contains 32, A3 diagrams

October 2023
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cgbri1 Images

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