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 first edition (ISO 6709:1983) was developed by ISO/IEC JTC 1/SC 32. Later the standard was transferred to ISO/TC211, Geographic information/Geomatics in 2001. The committee completely revised the second edition (ISO 6709:2008). There was a short technical corrigendum (ISO 6709:2008/Cor 1:2009) released in 2009. The second edition consists of a main part and eight annexes (Annexes A through H). The main part and Annexes A and C give encoding-independent general rules to define items to specify geographic point(s). Annex D suggests a display style for human interface. Annexes F and G suggest styles of XML expression. Annex H suggests string expression, which supersedes the first edition of the standard. General rules Items A geographical point is specified by the following four items: First horizontal coordinate (ϕ or y), such as latitude (negative number south of equator and positive north of equator) Second horizontal coordinate (λ or x), such as longitude (negative values west of Prime Meridian and positive values east of Prime Meridian) Vertical coordinate, i.e. height or depth (optional) Identification of coordinate reference system (CRS) (optional) The first three items are numerical values called coordinates. The CRS gives the relationship between the coordinates and a point on the earth. The identification of CRS could be a full description of properties defined in ISO 19111; only an identifier given by some registry (such as EPSG) is used in most cases, since only such identification is enough for most information exchange purposes. Order, sign, and units Order, positive direction, and units of coordinates are supposed to be defined by the CRS. When CRS identification is missing, the data must be interpreted by the following conventions: Latitude comes before longitude North latitude is positive East longitude is positive Fraction of degrees (decimal degrees) is preferred in digital data exchange, while sexagesimal notation is tolerated for compatibility There is no such interpretation rule for vertical coordinates. Representation at the human interface (Annex D) When there is no guideline given from the user community, the following styles are suggested: Coordinate values (latitude, longitude, and altitude) should be delimited by spaces. The decimal point is a part of the value, thus must usually be configured by the operating system. Multiple locations should be represented by multiple lines. Latitude and longitude