From fortress flagpole to the Greenwich line: The establishment of a common prime meridian in Norway in the period 1770–1970

The author analyses the use of prime meridians on selected Norwegian maps in the period 1770–1970. The aim is to show the progression from a time of multiple local prime meridians, through a period in which Sweden tried to impose cartographic unity on the two countries, to the decades after Norwegian political independence in 1905 and the establishment of the Greenwich longitudinal line as the prime meridian on Norwegian maps. Comparative...