What3words


What3words is a geocoding system for the communication of locations with a resolution of three meters. What3words encodes geographic coordinates into three dictionary words; the encoding is permanently fixed. For example, the omphalos of Delphi, believed by the ancient Greeks to be the center of the world, is located at "spooky.solemn.huggers". What3words differs from most other location encoding systems in that it displays three words rather than long strings of numbers or letters. What3words has a website, apps for iOS and Android, and an API that enables the bidirectional conversion between what3words address and latitude/longitude coordinates. As the system relies on a fixed algorithm rather than a large database of every location on earth, it works on devices with limited storage and no Internet connection. According to the company, its revenue comes from charging businesses for high-volume use of the API that converts between 3 words and coordinates; services for other users are free of charge.

What3words uses a grid of the world made up of 57 x1012 squares of 3 meters by 3 meters. Each square has been given an address composed of three words. The addresses are available in 36 languages according to the what3words online map (as of April 2019), and the addresses are not translations of the same words. Each what3words language uses a wordlist of 25,000 words (40,000 in English, as it covers the sea as well as land). The lists go through multiple automated and human processes before being sorted by an algorithm that takes into account word length, distinctiveness, frequency, and ease of spelling and pronunciation. Homophones and variant spellings[18] are treated to minimize any potential for confusion, and offensive words are removed.

The what3words algorithm actively distributes similar-sounding three-word combinations around the world to enable both human and automated error-checking. The result is that if a three-word combination is entered slightly incorrectly and the result is still a valid what3words reference, the location will usually be so far away from the user's intended area that the error will be immediately obvious to both a user and an intelligent error-checking system. The what3words system uses a proprietary algorithm in combination with a limited database; the core technology is contained within a file of about 10 MB. The database is used to assign more memorable words to locations in urban areas. What3words originally sold "OneWord" addresses, which were stored in a database for a yearly fee, but this feature has been canceled. The main claimed advantages of what3words are memorability, error-detection, unambiguous nature of words for almost every day and non-technical users, and voice input.