**9. Geodetic latitude (Ф)**

The geodetic latitude is the geographical latitude. The geodetic is the angle between normal line on the geoid (which is approximately the earth shape) at any point on the earth and the plane of equator (which approximately the earth shape). The geodetic latitude is differ from geocentric latitude because of elliptical shape of the earth.

The geodetic latitude - geocentric latitude = 11.7 sin 2Ф in minutes of arc. The maximum value difference between them is about 21.5 km. at latitude 45°.
