Message #2697

[Morrison]

Description of Piri Reis

The Piri Reis map seems as distorted as can be expected for an old map. However, if one takes small areas, the map is remarkably accurate within this small area, see e.g. Europe. In the area of South America, it correctly shows the position of capes and rivers. This accuracy is present in most areas of the map. This may be due to the fact that Reis compiled his map from other older and much older ones that were available to him from the Imperial library at Constantinople, at that time a centre of civilization.

The second remarkable thing is the grids overlaying the contours. These grids display latitude (north-south) and longitude (east-west) to a high degree of accuracy (see an analysis). The latitude is not remarkable; it can be measured by the height of the sun above the horizon. Longitude is, because in fact it is only possible to measure this by accurately measuring time. In fact, the first known person to achieve this accuracy was John Harrison in 1716, who made his clocks in response to a competition organized by the British admiralty, after a small fleet of warships was lost when hitting cliffs after a navigational error in longitude (by the way, Harrison got a similar treatment as Hapgood, in his case because he was of lowly social class, which is another fine way to judge someone’s work).

The third remarkable thing is that what was initially seen as an arbitrary distortion of the large scale features, in fact turned out to be explainable by changing ones view of the earth. The earth is a globe, so all maps, being flat, are distorted, and the only thing to do is to choose ones kind of distortion, which is called a mathematical projection. The Piri Reis map is a projection that looks like a view from a fixed point, like taking a globe and holding it for your eyes, see here. In order to make such a map, one could use the method just mentioned, or have another accurate map, and do mathematical calculations to transform it to this view. However, in this source map too the knowledge of the earth being a globe has to be present, and has to know spherical trigonometry.

The fourth remarkable thing is that the map shows the Antarctic. If the knowledge compiled by the map comes from sailors, these sailors must have navigated throughout the northern part of the Antarctic regularly, in order to gather the data shown on the map.

The fifth remarkable thing is that the contours of the Antarctic it shows are its land contours as it presently lies under a thick layer of ice. This fact came to the fore after Hapgood had asked the military about these features of the map, see the response he got here (to come).