Using GIS and historical digitized aerial imagery and maps to analyse information on Cold War Soviet military maps of Denmark

During the Cold War, the General Staff of the Soviet Union secretly mapped foreign coun-tries for military purposes. Being a military se-cret until the fall of the Soviet Union, research into the cartographic heritage of this global mapping enterprise has only emerged in re-cent years. The geographical information in these Soviet maps was based on a wide range of sources, among them remote sensing, field survey, other topographical maps and even in-formation collected by spies (Davies and Kent 2017). However, Davies and Kent mainly focus on maps from United States and United King-dom. Following the research agenda set by Davies and Kent, this paper focus on analysingthe Soviet military mapping of Denmark, based on the collection of Soviet maps at held the Royal Danish Library. The analysis focuses both on identifying the source of information for the production of these maps as well as their cartographic quality. We propose a GIS-based approach to investi-gate the origin of the topographical infor-mation on Soviet military maps, utilizing the extensive collection of more than one million geo-located historical aerial photographs as well as a collection of digitized topographical maps covering Denmark. The proposed method is based on the following steps; (1) Scanning and geo-referencing of the Soviet military maps, (2) selection of areas/map sheets to be included in the analysis, (3) com-parison of geometry and places names/labels with contemporary Danish maps, (4) compari-son of geometry with historical aerial imageryin order to date the geographical information contained in Soviet maps, (5) assessment of the quality of information through compari-son with contemporary Danish maps and de-classified information about places of military importance. (Reference: Davies, John, and Alexander Kent. 2017. The Red Atlas: How the Soviet Union Se-cretly Mapped the World. Chicago; London: University of Chicago Press.)