Portolan Map Possibilities

[Linda]

Interesting. This book, which i just started to read, has already given a correlation between the rosettes map and a portolan chart.

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It says that a distinguishing feature of portolan charts is the alignment of Tangiers - Jerba - Alexandra as the horizontal baseline for the map.

I believe Tangier is shown at the top NW corner. Well, the westernmost part of the promontory on which it is located, Tangier itself would be hidden under the rosette.



I think the vms shows the area better than the Piri Reis map from the 16th century, which is oriented west up as well. The Piri Reis doesnt show enough straight section east of Tarifa, nor of Tangier, and matches the tips up too closely, both in terms of proximity and of alignment.  The rosette map has all of it right. Perhaps it did not go far enough west with the southern promontory, but then, it is cut off, so can be seen to extend even further than shown. Actually, perhaps Tangier is off map, and this is the curve to the east of Tangier. This would make it almost a perfect representation of the actual situation.

The NW rosette would be the SW rosette in terms of this portolan horizontal bottom alignment, so give the rosettes map a quarter turn to match up with the modern north up map, so the sun is on the left bottom. The sun is basically the location of the area west of Tangier, the rest is an indication of elevation, ignore that part and concentrate on the rounded area around the sun being the actual shore being shown, the rest is an indication of height, not extended shoreline. Here is an elevation map to support that argument.



Tangier itself is near the lower lying area between the mountainous parts and would be located under the rosette, or off map to the west, if it is the area to the east of it being displayed. Either way, this promontory is then seen to be situated quite a bit to the west of the northern tip at Tarifa, and the angle of the shoreline east of Tarifa is correct. Gibraltar and Ceuta are also hidden by the tower in the hole bridge and rosette/tubes respectively. 



I had seen the tubes as representing Ceuta, but in another morph as Tunisia. You can see the similarities of each in the images above and below respectively. Similarly, the curvy bridge can be seen to be both the Gulf of Gabes, since it is the next curve after the Tunisian peninsula, but also representative of the Gulf of Sidra, or the two of them together, since between the two of them they make one large depression, or curve, albeit somewhat rectangular, in the shoreline.



With either interpretation it can be seen that Tangier is in alignment with Jerba/Djerba on the Rosette map, although it is not really the case in terms of reality.



Here is a map showing Alexandria and Giza. I believe the bridge between W and SW rosettes shows the pyramids of Giza, seen from above and lined up on top of each other, instead of beside. I think it is a good analogy for alignment, while avoiding the immediately recognizable pyramid shapes, whereas in another way, when you turn it back into the pyramids, you get the analogy with triangles, or deltas. I believe it is meant to represent the portion of Egypt west of the Nile, which is represented by the SW rosette. I think it is analogous to the location of Alexandria, which too is the western point of the Nile delta, which actually also looks more like a rhomboid than a triangle.



The W rosette in the inital alignment of the rosettes would stand for Libya. And now it can be seen that Jerba is in alignment with Alexandria and also with Tangier, as we saw earlier.

In conclusion, it appears the Rosette map qualifies as displaying the distinguishing feature of Tangier - Jerba - Alexandria horizontal baseline alignment inherent of portolan charts, when the map is rotated so the NW rosette becomes the SW rosette. This could mean it is the framework for the creation of an actual portolan chart, or to reference one.