# parametric latitude

From EngHydroDic

The angle at the centre of a sphere which is tangent to the spheroid along the geodetic equator, between the plane of the equator and the radius to the point intersected on the sphere by a straight line perpendicular to the plane of the equator and passing through the point on the spheroid whose parametric latitude is defined. Parametric latitude is an auxiliary latitude used in problems of geodesy and cartography. Also called reduced latitude, geometric latitude or eccentric angle.