EPSG Code

An EPSG code is a numeric identifier in the EPSG Geodetic Parameter Dataset that names a specific coordinate reference system, datum, ellipsoid, or transformation. The dataset, maintained by the IOGP geodesy subcommittee, lets software unambiguously reference a CRS by integer instead of a full parameter list. EPSG:4326 is geographic WGS 84 (latitude/longitude), and EPSG:32601 through 32660 are the WGS 84 UTM north zones, for example EPSG:32633 for UTM zone 33N. GIS and hydrographic software tag every dataset with an EPSG code so coordinates transform correctly; a mismatched or missing code is a common source of horizontal positioning error.