|Reference ellipsoid for World Geodetic System 1984|
|Mean radius of planet Earth|
|Ellipsoidal radii of curvature|
|Radii of auxiliary spheres|
|Convert geodetic to geocentric latitude|
|Convert geodetic to parametric latitude|
|Convert geocentric to geodetic latitude|
|Convert parametric to geodetic latitude|
|Eccentricity of ellipse from axes lengths|
|Semimajor axis of ellipse|
|Semiminor axis of ellipse|
|Flattening of ellipse from eccentricity|
|Eccentricity of ellipse from flattening|
|Third flattening of ellipse from eccentricity|
|Eccentricity of ellipse from third flattening|
The Earth can be modeled as a perfect sphere, an oblate spheroid, an ellipsoid, or a geoid.
A reference spheroid is a model of a roughly-spherical astronomical body.
Use reference spheroids to create map projections, to calculate curves and areas on the surface of a spheroid, and to transform 3-D geodetic coordinates.