Shape of the Reference System

In Section 3, Octet 15
(Does not apply to grid templates 50-53, 100, 120, and 1200)

Revised 06/21/2022

Code Figure Meaning
Earth assumed spherical with radius = 6,367,470.0 m
Earth assumed spherical with radius specified (in m) by data producer
Earth assumed oblate spheriod 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)
Earth assumed oblate spheriod with major and minor axes specified (in km) by data producer
Earth assumed oblate spheriod as defined in IAG-GRS80 model (major axis = 6,378,137.0 m, minor axis = 6,356,752.314 m, f = 1/298.257222101)
Earth assumed represented by WGS84 (as used by ICAO since 1998) (Uses IAG-GRS80 as a basis)
6 Earth assumed spherical with radius = 6,371,229.0 m
7 Earth assumed oblate spheroid with major and minor axes specified (in m) by data producer
8 Earth model assumed spherical with radius 6,371,200 m, but the horizontal datum of the resulting Latitude/Longitude field is the WGS84 reference frame
9 Earth represented by the OSGB 1936 Datum, using the Airy_1830 Spheroid, the Greenwich meridian as 0 Longitude, 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". (see Note 1)
11 Sun assumed spherical with radius = 695 990 000 m (Allen, C.W., Astrophysical Quantities, 3rd ed.; Athlone: London, 1976) 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, Astron. Astrophys. 2006, 449, 791-803)
Reserved for Local Use


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

(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).