ISO 6709, Standard representation of geographic point location by coordinates, is the international standard for representation of latitude, longitude and altitude for geographic point locations.
The main part and Annexes A and C give encoding-independent general rules to define items to specify geographic point(s).
Order, positive direction, and units of coordinates are supposed to be defined by the CRS.
When there is no guideline given from the user community, the following styles are suggested: Examples: The standard does not specify how coordinates at the equator, prime meridian or antimeridian should be written.
A string expression of a point consists of latitude, longitude, height or depth, CRS identifier, and trailing solidus (/) without any delimiting character.
The fractional part must have the appropriate number of digits to represent the required precision of the coordinate.