geocentric latitude

The geocentric latitude is not the appropriate up direction for the local tangent plane.

Note the closeness of the conformal and geocentric latitudes.

The geocentric latitude is the angle between the equatorial plane and the radius from the centre to a point on the surface.

A prior version of this page showed use of the geocentric latitude ().

The geodetic and geocentric latitudes are equal at the equator and poles.

The calculated values are approximations due to the distinction between common/geodetic latitude and geocentric latitude.

If the original geodetic latitude is available it should be used, otherwise, the relationship between geodetic and geocentric latitude has an altitude dependency, and is captured by:

Since the normal at a general point on the ellipsoid does not pass through the centre it is clear that points on the normal, which all have the same geodetic latitude, will have differing geocentric latitudes.

It can be shown that the distance is more accurately determined if the positions of the source and the station are expressed in terms of geocentric latitude (the angle subtended at the centre of the Earth) rather than geographic latitude.

The isometric latitude is conventionally denoted by ψ (not to be confused with the geocentric latitude): it is used in the development of the ellipsoidal versions of the normal Mercator projection and the Transverse Mercator projection.

Geodetic latitude is determined by the angle between the equatorial plane and normal to the ellipsoid, whereas geocentric latitude is determined by the angle between the equatorial plane and line joining the point to the centre of the ellipsoid (see figure).

A point on the ellipsoid can mapped radially onto the sphere along the line connecting it with the center of the ellipsoid; this maps a point of latitude on the ellipsoid to a point on the sphere with latitude , the geocentric latitude.