ISO 6709:1983

Standard representation of latitude, longitude and altitude for geographic point locations

Describes a variable-length format for the representation of latitude, longitude and altitude for use in data interchange. Allows the use of normal sexagesimal notations involving degrees, minutes and seconds as well as various combinations of sexagesimal and decimal notations. Uses numeric characters 0 to 9, graphic characters plus (+), minus (-), full stop (.) and comma (,).