Null Island is a name for the point on the Earth's surface where the prime meridian and the equator cross, located in international waters in the Gulf of Guinea (Atlantic Ocean) off the west African coast. In the WGS84 datum, this is at zero degrees latitude and longitude ( ), and is the location of a buoy. The name 'Null Island' serves as both a joke based around the suppositional existence of an island there and as a name to which coordinates erroneously set to 0,0 are assigned in placenames databases in order to more easily find and fix them. The nearest land is a small islet offshore of Ghana, between Akwidaa and Dixcove at , 307.8 nmi (354.2 mi; 570.0 km) to the north. The seabed depth at this place is around 4,940 metres (16,210 ft).
In terms of computing and placenames databases, the coordinates for Null Island were added to the Natural Earth public domain map dataset c. 2010–2011, after which the term came into wide use (although there is evidence of it being used previously). Since then, the 'island' has through fiction been given a geography (based on the setting of the video game Myst), history, and flag. Natural Earth describes the entity as a "1 meter square island" with "scale rank 100, indicating it should never be shown in mapping". The name 'Null' refers to the two zero coordinates, as null values (indicating an absence of data) are often coerced to a value of 0 when converted to an integer context or "no-nulls allowed" context.
The location is used by mapping systems to trap errors. Such errors arise, for example, where an image artifact is erroneously associated to the location by software which cannot attribute a geoposition, and instead associates a latitude and longitude of "Null,Null" or "0,0".
Other data mapped to the location include activity events from the Strava fitness-tracking app, apparently (as reported in January 2018 by Bellingcat) mapped to the location due to users entering "0,0" coordinates to disguise their real location.
There is a moored weather and sea observation buoy at 0.000 N 0.000 E (0°0'0"N 0°0'0"W). This buoy ("Station 13010 - Soul") is part of the PIRATA system operated jointly by the United States, France, and Brazil.
- Colonel Bleep, a 1957 cartoon that took place on the fictitious Zero Zero Island, at the same location as Null Island, where earth's equator meets the Greenwich Meridian.
- Potwin, Kansas, site of a similar default location, being close to the geographic centre of the contiguous United States.
- St. Onge, Tim. "The Geographical Oddity of Null Island". Library of Congress. Archived from the original on 12 May 2016. Retrieved 13 May 2016.
- "Bathymetric Data Viewer". National Geophysical Data Center (NGDC). National Oceanic and Atmospheric Administration. Archived from the original on 9 July 2017. Retrieved 2 July 2017.
- Kurgan, Laura (2013). Close Up at a Distance: Mapping, Technology and Politics. New York: Zone Books. p. 157. ISBN 9781935408284.
- "Natural Earth version 1.3 release notes". 2011-01-31. Archived from the original on 4 October 2013. Retrieved 1 October 2013.
- Hotz, Robert Lee (14 July 2016). "If You Can't Follow Directions, You'll End Up on Null Island". Wall Street Journal. Archived from the original on 13 July 2016. Retrieved 14 July 2016.
- "We call that spot "Null Island"". 2009-04-17. Archived from the original on 2018-09-10. Retrieved 2018-09-10.
- "Null Island is One of the Most Visited Places on Earth. Too Bad It Doesn't Exist". Archived from the original on 25 August 2017. Retrieved 25 August 2017.
- Aric, Toler (29 January 2018). "How to Use and Interpret Data from Strava's Activity Map - bellingcat". Bellingcat. Retrieved 2 February 2018.
- "Station 13010 - Soul". National Data Buoy Center. Retrieved 15 May 2020.
- Media related to Null Island at Wikimedia Commons