text: what is latitude and what is longitude?   (m)  latitude, usually denoted symbolically by the greek letter φ, gives the location of a place on earth north or south of the equator. latitude is an angular measurement ranging from 0° at the equator to 90° at the poles (90° n or 90° s). co-latitude is the complement of latitude.  longitude, sometimes denoted by the greek letter λ, describes the location of a place on earth east or west of a north-south line called the prime meridian. longitude is given as an angular measurement ranging from 0° at the prime meridian to +180° eastward and −180° westward. unlike latitude, which has the equator as a natural starting position, there is no natural starting position for longitude. therefore, a reference meridian had to be chosen. while british cartographers had long used the greenwich meridian in london, other references were used elsewhere, including: el hierro, rome, copenhagen, jerusalem, saint petersburg, pisa, paris, philadelphia and washington. in 1884, the international meridian conference adopted the greenwich meridian as the universal prime meridian or zero point of longitude.