Mapped by the Enemy - Foreign Military Mapping of Denmark in the 20th century

In recent years, the geopolitical situation in Europe has deteriorated, and maps and geographic information have once again become critical assets. Precise maps and geographic information are crucial for the projection of military power, which is also the reason for censorship and concealment of critical information that were applied to topographic maps in most European countries in the 20th century to disguise critical information from foreign powers. This is also the case in Denmark, where official topographic maps for public use were censored to conceal information about military installations and critical infrastructure, such as power lines, transformer stations and rail yards.

Denmark's strategic location at the approaches to the Baltics has attracted interest from foreign powers in mapping Danish territory throughout the 20th century. Most well-known are the topographic maps and city plans of Denmark made by Germany and the United Kingdom during the Second World War and Soviet maps during the Cold War. However, topographic maps and city plans were also published by countries such as Sweden, Poland, East Germany, and the USA. Yet, little is known about these mapping efforts by foreign powers, as well as the effectiveness of the Danish measures to conceal information from foreign powers.

In a recent project, the Royal Danish Library digitized its complete collection of more than 3,000 foreign made topographic maps of Danish territory between 1900 and 1990 and made the maps available online.

This presentation offers an analysis of the Royal Danish Library's collection of maps of Denmark produced by foreign powers. Through specific examples from the collection, the presentation will investigate the methods and data sources employed by these foreign entities, while also discussing how effectively Denmark has concealed geographic information regarding critical military and societal infrastructure.

In conclusion, the presentation reflects on the degree to which history can inform current debate about the protection of sensitive geographical data.