# Section 3 - Code Table 2 : Shape of the reference system

## Code Tables for Section 3

## More Sections

Code | Meaning |

0 | Earth assumed spherical with radius = 6 367 470.0 m |

1 | Earth assumed spherical with radius specified (in m) by data producer |

2 | Earth assumed oblate spheroid with size as determined by IAU in 1965 (major axis = 6 378 160.0 m, minor axis = 6 356 775.0 m, f = 1/297.0) |

3 | Earth assumed oblate spheroid with major and minor axes specified (in km) by data producer |

4 | Earth assumed oblate spheroid as defined in IAG-GRS80 model (major axis = 6 378 137.0 m, minor axis = 6 356 752.314 m, f = 1/298.257 222 101) |

5 | Earth assumed represented by WGS-84 (as used by ICAO since 1998) |

6 | Earth assumed spherical with radius of 6 371 229.0 m |

7 | Earth assumed oblate spheroid with major or minor axes specified (in m) by data producer |

8 | Earth model assumed spherical with radius of 6 371 200 m, but the horizontal datum of the resulting latitude/longitude field is the WGS-84 reference frame |

9 | Earth represented by the Ordnance Survey Great Britain 1936 Datum, using the Airy 1830 Spheroid, the Greenwich meridian as 0 longitude, and the Newlyn datum as mean sea level, 0 height |

10 | Earth model assumed WGS84 with corrected geomagnetic coordinates (latitude and longitude) defined by Gustafsson et al., 1992 |

11 | Sun assumed spherical with radius = 695,990,000 m (Allen, C.W., 1976 Astrophysical Quantities (3rd Ed.; London: Athlone) and Stonyhurst latitude and longitude system with origin at the intersection of the solar central meridian (as seen from Earth) and the solar equator (Thompson, W, Coordinate systems for solar image data, A&A 449, 791–803 (2006)) |

255 | Missing |

( 1) WGS84 is a geodetic system that uses IAG-GRS80 as basis.

( 2) With respect to code figures 0, 1, 3, 6 and 7, coordinates can only be unambiguously interpreted, if the coordinate reference system in which they are embedded is known. Therefore, defining the shape of the Earth alone without coordinate system axis origins is ambiguous. Generally, the prime meridian defined in the geodetic system WGS-84 can be safely assumed to be the longitudinal origin. However, because these code figures do not specify the longitudinal origin explicitly, it is suggested to contact the originating centre if high precision coordinates are needed, in order to obtain the precise details of the coordinate system used (effective as from 16 November 2016).