To draw the map of the oikumene (that is, the inhabited world) using the first cartographic method, Ptolemy (ca. 100-ca. 175 CE) certainly had at his disposal a globe on which to measure geographic coordinates. He begins by plotting the central meridian, which is the straight line generating the cone divided into 131 and a half parts. The line is marked off into 34 parts. Ptolemy then constructs a rectangle with a length equal to twice its height, forming the boundary of the area depicted on the map. The first parallel drawn is the one passing through the island of Rhodes, which, on the map, consists of an arc of a circle with a radius of 79 parts. Because the meridians converge toward the poles, the 5° value on the Rhodes parallel is equivalent to 4° on the Equator or the meridian. Taking the interval of 4 parts on the central line, Ptolemy therefore transfers it to the arc of the Rhodes parallel, 18 times to the right and 18 to the left. He can thus draw the radial lines bounding the longitudinal extension of the oikumene. He then measures a radius of 52 parts to draw the parallel passing through Thule. With a radius of 115 parts, he draws the Equator. And with a radius of 131 and a half parts—that is, the entire central line—he draws what is known as the anti-Meroë parallel. At this point, Ptolemy notes that the ratio of the radius of the Equator and that of the Thule parallel—that is, 115:52—is equivalent to the ratio measured between the same circles on the globe. His next step is to draw the meridians, which, unlike the parallels, turn into radial straight lines. Ptolemy draws them up to the Equator, because beyond that limit they become distorted, converging in the opposite direction. To define this distortion, Ptolemy draws the parallel passing through the city of Meroë, at 16°30' north. He then measures the 5° interval and transposes it to the arc of the anti-Meroë parallel, thus drawing the southern meridians. Having built the cartographic grid of meridians and parallels, Ptolemy plots the positions of the most noteworthy cities and places. Every location is identified by two latitude and longitude coordinates that are marked on the map with the aid of a ruler and compass. The mapmaker then draws the coastlines, rivers, and mountain ranges, the wind directions, and place names. At this point, the geometer gives way to the painter, who will enhance the visual appearance of the map.