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

ABSTRACT

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 methods were used to study both analogue and digitized versions of maps, as well as literature from the study period. Additionally, for some of the maps, the reasons for the choice of prime meridian were explored and the maps were considered in a political context. Relevant international circumstances included the cartographic controversy between France and Britain and the prime meridian of Philadelphia as a symbol of American independence. The results revealed that Norwegian prime meridians were used as a political instrument. The author concludes that Sweden did not succeed in its geopolitical ambition to unify Scandinavian cartography, and that the use of varying prime meridians on Norwegian maps was only gradually ended by national unity.

KEYWORDS:

• cartography
• maps
• political independence
• political instrument
• prime meridian

Notes

1 In addition to the named meridians, the term ‘den første meridian’ (the first meridian) was widely used, and the term ‘utgangsmeridian’ (starting meridian) appears on a number of maps.

2 The capital of Norway, Oslo, was named Christiania in the period 1624–1925 (also spelt Kristiania from c.1880) and was renamed Oslo in 1925. The name of the prime meridian through the city changed accordingly.

3 Norges Grændsers Opmåling, later named Norges Geografiske Opmåling (NGO), are the historical names of the present-day Norwegian Mapping Authority.

4 Information about the letter was sourced from Geodetiska arkivet, Lantmäteriverket, but the original version no longer exists.

5 In Sweden, various terms were used for meridians, including nollmeridian (zero meridian) from which longitude was calculated (i.e. Stockholm) and medelmeridian (middle meridian), which was also named huvudmeridianen (main meridian), the meridian due north in the map projection (i.e. 5° west of Stockholm) (M. Ekman, personal communication 2018). Additionally, referensmeridian (reference meridian) appears in Swedish literature.

6 The map was accessed from National Library of Norway in 2018: Map 14.1. 00930: Speciel Kaart Over en Deel af Den norske Kyst: Trondhjem-Kristiansund, 1:225 000, by C.F. Grove, 1791.