Binocular Vision and Stereopsis, Ian P. Howard, Brian J. Rogers, pp. 236, Oxford University Press, 1995, ISBN 978-0-19-508476-4, ... the azimuth of a point is defined as the dihedral angle between a vertical plane passing through the point ...
Relational Management and Display of Site Environmental Data, David Rich, pp. 246, CRC Press, 2002, ISBN 978-1-56670-591-2, ... The earth is roughly spherical, and the latitude-longitude system is used to describe locations in spherical coordinates. Latitude is measured in degrees (l/360th of the sphere) north or south of the equator. Longitude is measured in degrees east (positive) or west (negative) of the prime meridian, which passes through Greenwich, England ...