Magnetic compass

technology

The magnetised needle used for direction-finding, developed in China from lodestone instruments used in divination and geomancy under the Han. Shen Kuo's Dream Pool Essays of 1088 describes the suspended magnetic needle and records that it does not point true south, the first known account of magnetic declination. Zhu Yu's Pingzhou Ketan of 1119 gives the first description of a compass used at sea, referring to voyages of the 1080s and 1090s. The first European mention is Alexander Neckam's around 1190. Its decisive effect was on the sea routes rather than the land ones: it made open-water navigation in poor visibility possible, and so helped shift trade volume from camel to hull. A technique, not a place.

A technology is not a place. Drawing it on a map would assert something about the world that no stored fact supports.