countrycityserial

Countrycityserial is a proposed naming and identification concept designed to produce unique identifiers for urban locations by combining a country code, a city code, and a sequential serial number. It is not an official standard, but a model used in data schemas and private databases for geographic indexing and record linkage.

The typical form comprises three components: a country code (commonly the ISO 3166-1 alpha-2 code), a city code (a short, three-letter abbreviation for the city), and a numeric serial that differentiates multiple records within the same city. An example is US-NYC-00123, which denotes a specific entry for New York City in the United States.

Applications include large-scale data integration, logistics, mapping, digital catalogs, and government information systems where stable, human-readable identifiers help merge records from diverse sources. The format aims to be more readable than opaque identifiers like UUIDs and to facilitate manual data entry or review in certain workflows.

Challenges involve achieving and maintaining a consistent city-code standard, handling changes in city boundaries or names, and addressing metropolitan areas that span multiple jurisdictions. Additionally, registry governance, privacy considerations, and cross-system interoperability must be managed to prevent conflicts and drift.

In practice, countrycityserial appears mainly in informal discussions or within private systems. It overlaps with established concepts such as locality codes, geocoding tables, and place identifiers, and is often compared to postal or airport codes while serving a different indexing purpose.

See also: ISO 3166, ISO 3166-2, locality code, geocoding, place identifiers.