Censorship of maps

Cartographic censorship describes the way of handling the appearance of potential strategically important objects like military bases, power plants or transmitters towards their censorship on maps. The appearance of such objects on maps available to the public may be undesirable, so it is often attempted to conceal these locations on the map.

A variant of censorship of maps is putting in false altitudes. This can be important for predicting flooding. In World War I many German soldiers were killed in Belgium after their camps were flooded, even though the maps used by German military indicated the camp sites were not prone to flooding.

Censorship of maps was also used in former East Germany, especially for the areas near the border to West Germany in order to make attempts of defection more difficult.

In the United Kingdom, during the Cold War period and shortly after, a number of military installations (including 'prohibited places') did not appear on commercially issued Ordnance Survey mapping. This practice was effectively curtailed with the mass availability of satellite imagery. Another aspect of map censorship in the UK is that the internal layout of HM Prison facilities were not shown on public OS mapping.

Censorship of maps is today still often applied, although it is less effective in the age of satellite picture services. A "dead map" is a term often applied to sensitive government maps that show the location of top secret facilities and other highly sensitive installations within a country. Russia, the United States and Great Britain all have such maps.

Google Earth censors places that may be of special security concern. The following is a selection of such concerns:

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