Geographic coordinates of a point, with an optional altitude.

Used by element ‘Distribution’.

:Parameters:

geodetic_datum : string, required
    the geodetic datum (also called 'map datum'). For example, Google's
    KML uses 'WGS84'.
lat : numeric
    latitude
long : numeric
    longitude
alt : numeric
    altitude
alt_unit : string
    unit for the altitude (e.g. 'meter')