what is another name for the prime meridian
Prime meridian A prime meridian is ultimately arbitrary, unlike an equator, which is determined by the axis of rotationâ€”and various conventions have been used or advocated in different regions and throughout history.[1] The most widely used modern meridian is the IERS Reference Meridian. It is derived but deviates slightly from the Greenwich Meridian, which was selected as an international standard in 1884.
Universal Transverse Mercator coordinate system The UTM system divides the Earth into 60 zones, each 6° of longitude in width. Zone 1 covers longitude 180° to 174° W; zone numbering increases eastward to zone 60, which covers longitude 174°E to 180°. The polar regions south of 80°S and north of 84°N are excluded.