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)