chaosmagpy.coordinate_utils.geo_to_gg(radius, theta)[source]

Compute geodetic colatitude and vertical height above the ellipsoid as defined by the World Geodetic System 1984 (WGS84) from geocentric radius and colatitude.

radiusndarray, shape (…)

Geocentric radius in kilometers.

thetandarray, shape (…)

Geocentric colatitude in degrees.

heightndarray, shape (…)

Altitude in kilometers.

betandarray, shape (…)

Geodetic colatitude in degrees.


Round-off errors might lead to a failure of the algorithm especially but not exclusively for points close to the geographic poles. Corresponding geodetic coordinates are returned as NaN.


Function uses Heikkinen’s algorithm taken from:

Zhu, J., “Conversion of Earth-centered Earth-fixed coordinates to geodetic coordinates”, IEEE Transactions on Aerospace and Electronic Systems, 1994, vol. 30, num. 3, pp. 957-961