You have never been to Null Island. In fact, we don’t suppose many people actually have. However, speaking in terms of digital geospatial data points, it's a place that's been documented time and time again.
Ok, enough with the riddles. Null Island is the jokey name given to the location at zero degrees latitude and zero degrees longitude. In other words, the intersection where Earth's prime meridian meets the equator. This works out to be a point in the Gulf of Guinea, a portion of the eastern tropical Atlantic Ocean off the west coast of Africa.
Since its geographical coordinates are 0°N 0°E, it is frequently recorded as the geographic point of a location that's been incorrectly inputted into a digital map.
As explained by the US Library of Congress blog, the bug can occur for several reasons. Often, it’s simply a typo from the slip of a finger. While entering a place’s location into a digital dataset, misspelled street names or confusing building numbers can invalidate the address and result in its coordinates being automatically logged as null, which the computer records as 0°N 0°E.
In the event of most errors or incomplete entries, the dodgy data point will be assigned to the coordinates 0°N 0°E.
Null Island has become a simple way of identifying problematic or erroneous geocodes on maps. If you’re looking to clean up errors in a geographical database, a good place to start is by searching the coordinates 0°N 0°E where you’re likely to find many bug-laden entries.
Data analysts noticed this quirk and started to jokingly call it “Null Island,” utilizing it as a means to track down geocode errors.
It’s not clear when the nickname arose, but the location of Null Island first appeared on Natural Earth, a public domain map maintained by volunteer geographers, before 2011.
In their words: “It is a fictional, 1-meter-square island located off Africa where the equator and prime meridian cross. Being centered at 0,0 (zero latitude, zero longitude) it is useful for flagging geocode failures which are routed to 0,0 by most mapping services.”
Of course, Null Island isn’t an actual landmass. However, if you literally sail out to the Gulf of Guinea towards the intersection between the world’s prime meridian and the equator, you will come across a large buoy.
Known as Station 13010 - Soul, the weather-monitoring buoy is part of the Prediction and Research Moored Array in the Atlantic (PIRATA) system that keeps tabs on the tropical Atlantic Ocean. Together with 16 other buoys, the floating weather station measures things like wind speed, air temperature, and humidity to help inform weather forecasts and climate models.
In the real world, Null Island is just a lone buoy floating in the Atlantic. However, in the virtual world, it's a hypothetical pin-point where misplaced data points lurk.