Censorship or Accident? Distinguishing Natural and Intentional Geometric Errors on Cold War City Plans Published in the Eastern Bloc

During the Cold War, maps published in Eastern Bloc countries were subject to strict censorship. From the 1960s, Warsaw Pact states were required to geometrically distort maps intended for public use, although methods varied by country. Some inaccuracies, however, may have resulted from technological limitations or restricted access to reliable source materials. This article proposes a methodology for distinguishing natural from deliberate errors by analysing the geometric accuracy of 43 twentieth-century maps using MapAnalyst, QGIS and ArcGIS Pro. The results show that intentional distortions can often be identified, although in ambiguous cases, such as tourist plans of Lublin, natural and deliberate errors are difficult to distinguish. This may indicate indirect censorship through restricted access to reliable reference sources. The study provides a methodological basis for comparative research on Cold War cartographic censorship and for interpreting errors in contemporary maps produced in countries where access to geographic information is restricted..