.The map provides an overview of the region between the Seine, Rhône, and Elbe rivers. Points outside this region have also been calculated, as they have proven to be relevant to the region as well. The relationship between coordinates and measurement points is calculated for each individual case in the mapping table. The mapping table can be downloaded below. The functionality and interaction of coordinates, measurement points, and mappings are explained in detail in the research paper “Ptolemy’s Coordinates and Antique Measurement Points,” which is also available on these pages.
About the map:
The measurement points—that is, the points used in antiquity to describe the location of a point on the Earth’s surface—are shown as red circles. The description always follows the same structure. After the description of the location, there is an indication of the type of interval used for the calculation—that is, whether a Greek or Gallic interval was used. This is followed by the name of the coordinate from which the calculation was made.
The calculated positions of the coordinates from which the measurement points were calculated are shown with blue circles.
Using these coordinates, the positions of additional points in the coordinate system could also be calculated. In this way, the coordinate system itself can be reconstructed. The 20th and 30th meridians have been illustrated between the 45th and 63rd parallels; the points are shown in brown.