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.
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:
- Former Indian president Abdul Kalam had expressed concern over the availability of high-resolution pictures of sensitive locations in India.
- Indian Space Research Organization says that Google Earth poses a security threat to India and seeks dialogue with Google officials.
- The South Korean government has expressed concern that the software offers images of the presidential palace and various military installations that could possibly be used by North Korea.
- Operators of the Lucas Heights nuclear reactor in Sydney, Australia asked Google to censor high resolution pictures of the facility. However, they later withdrew the request.
- The government of Israel also expressed concern over the availability of high-resolution pictures of sensitive locations in its territory, and applied pressure to have Israeli territory (and the Occupied Territories held by Israeli forces) appear in less clear detail.
- The Vice President of the United States' residence (Naval Observatory) in Washington, DC has been pixelated, as has the Federal Gold Depository at Fort Knox.
- From June 2007 until January 2009, downtown Washington, DC was shown using USGS aerial photography from the spring 2002, while the rest of the District of Columbia was shown using imagery from 2005.
In Lebanon, all maps concerning the country are property of the Lebanese Army and are issued by the Directory of Geographic affairs of the Lebanese military. It is considered a felony to reproduce whole or portions of maps without the permission of the military, although maps can be issued to certain universities and urban design schools for use by students and can be issued to civilian upon presenting certain documents. A notice is written on the maps prohibiting reproduction, copying or sale of the map and that it should be returned to the Ministry of National Defense upon request. This policy is meant to prohibit terrorists, outlaws, and entities that are at war with Lebanon from obtaining those maps.
Lists of air traffic obstacles may not be published by many countries as many of them are strategically important (chimneys of power stations, radio masts, etc.)
- India: Stop Looking At Me, Google!
- Google Earth Poses Security Threat to India, ISRO Chief seeks Dialogue
- Lucas Heights nervous about Google gander
- Israel's top secret sites on Google Earth Archived January 8, 2011, at the Wayback Machine.
- Nikolas Schiller (Jan 21, 2009). "Google FINALLY updates the imagery of Washington, DC and now you can kinda see the message on my rooftop". Blog. The Daily Render. Retrieved 2009-01-21.
- Jenna Johnson (2007-07-22). "Google's View of D.C. Melds New and Sharp, Old and Fuzzy". News. Washington Post. Retrieved 2007-07-22.
- Neocleous, Mark (2003). "The violence of cartography". Imagining the state. McGraw-Hill International. ISBN 978-0-335-20351-2.
- Harley, John Brian (1988a). "Silences and Secrecy: The Hidden Agenda of Cartography in Early Modern Europe". Imago Mundi. 40: 57–76. doi:10.1080/03085698808592639. JSTOR 1151014.
- Harley, John Brian (1988b). "Maps, Knowledge, and Power". In Cosgrove, Denis; Daniels, Stephens. Iconography of Landscape: Essays on the Symbolic Representation, Design, and Use of Past Environments. Cambridge: Cambridge University Press. ISBN 978-0-521-38915-0.