Mapping Egypt
The topographic atlas was the last installment of the Description de l’Égypte, published in 1828. Ironically, the atlas of maps was to have been the first segment, providing a basis for all of the studies that followed of the antiquities, natural history, and modern state of Egypt. The French contingent of scientists and engineers was certainly well qualified to gather the necessary information, since there were a large number of topographical and civil engineers in the group. Thirty-seven of them, in fact, were responsible for gathering the necessary data for the new map of Egypt. Colonel Pierre Jacotin of the Corps of Topographical Engineers directed the field work, and then supervised the drawing of the maps and engraving of the plates for their eventual publication.
The results are remarkable, considering the difficult conditions under which the data was gathered. The surveyors suffered from lack of time, lack of armed escorts, and lack of precision instruments, many of which had gone to the bottom of the Mediterranean when the ship carrying them, the Patriote, ran aground and sank on the way from France.
The best map of Egypt that was available to the French expedition was one from 1765, which meant it was more than thirty years old before Napoleon’s forces arrived in Alexandria. It had been compiled from books and from other maps by a cartographer named Bourguignon d’Anville, and it gave a good overall impression of the Nile Valley and the Delta. It could not provide much accuracy, since it was not based on actual observations and measurement with instruments.
That is what the French engineers and surveyors in Napoleon’s expedition were trained to do. Every place they went was surveyed, measured off with chains, and fixed to circle sightings made by the expedition astronomer, Nicolas-Auguste Nouet. The resulting map sections were exceptionally detailed, as we can see in a detail of the cataracts of Upper Egypt, which includes Philae, Syene, and Elephantine. The completed map turned out to be so superior that the French military convinced Napoleon to keep it sealed and unpublished as a state secret. As a result, the map that is printed as the first plate in the antiquities volume of the Description de l’Égypte is d’Anville’s out-dated map of 1765.
Not until 1814, when Napoleon was first exiled to Elba, did the compilers of the expedition map of Egypt receive permission to publish it. Twenty-three engravers were put to work to produce the 47 sheets of the topographic map that starts at the south end of Egypt and proceeds to the Delta and Mediterranean in the north. It was printed on the largest paper available. The work finally appeared in 1828, more as a supplement than as a part of the Description de l’Égypte. Place names were given in both French and Arabic characters. The compilers were extremely concerned about accuracy, so the engraver who was responsible for the Arabic characters received special training and was tested for his competency.
The final result resembles a modern satellite or aerial map in precision and detail. To determine the longitude of Egyptian locations with respect to the Paris Meridian required accurate clocks to compare the time of certain astronomical events with the known time of those events in Paris. But the chronometer results were not reliable, and the cartographers could only approximate the longitude on the map relative to the Paris Meridian. Instead, the coordinate grid used to establish the relative positions of Egyptian locations was based on a meridian passing through the tip of the Great Pyramid of Giza and a latitude line at right angles to it. Everything could be plotted from these coordinates, which was an acknowledgement of the precision of the north-south alignment of the Great Pyramid. Its four sides are almost perfectly aligned with the four cardinal points of the compass.