ABSTRACT
This chapter offers a ‘prehistory’ of modern geospatial technologies. It reviews the technological systems used in determining one’s location on the Earth’s surface, in terms of latitude and longitude, beyond the experiential and approximate practices of navigating by landmarks and deductive reckoning. It explores the instrumentation (mariner’s astrolabe and quadrant, kamal, cross staff, back staff, octant, sextant, chronometer, time balls, transversal and vernier scales), and the astronomical knowledge and institutions required to determine latitude at sea (from the fifteenth century), longitude on land (by ‘eclipses of Jupiter’s satellites’, from the late seventeenth century), longitude at sea (by ‘lunar distances’ and chronometers, from the eighteenth century), and the hydrographic chart (from the nineteenth century). Throughout, location of features on the Earth’s surface was determined relatively, with respect to other features; only with the standardization of time and longitude in 1884 could location be considered an absolute attribute of phenomena, although even then the technologies remained highly specialized and accessible only to a few.
