The Prime Meridian, which passes through the Royal Observatory in Greenwich, England, is the zero point for the measurement of longitude. East of there, into Europe and on into Asia, it's "east longitude"; to the west, through Ireland, across the Atlantic and across the Americas, it is "west longitude".
They meet each other at the 180 degree mark, which is pretty much in the middle of the Pacific Ocean. So if you are sailing west from Hawaii toward the Philippines, your longitude will increase. At some point you're going to cross 179 degrees 59 minutes of west longitude, sail another mile or so to 180 degrees of longitude (which is neither east nor west, or perhaps it's both!) and then sail another mile to 179 degrees, 59 minutes EAST longitude. From then on into Asia, your longitude will steadily decrease.
The distance from the prime meridian is usually measured in degrees of longitude. The distance east or west of the prime meridian is referred to as "longitude."
The distance east or west of the prime meridian?
The distance east or west from the Prime Meridian is measured in degrees, with 360 degrees in a full circle representing the Earth's circumference. The Prime Meridian itself is set at 0 degrees longitude, so any location east of it will have a positive longitude value, while any location west of it will have a negative longitude value.
Longitude !
prime meridian
Yes.
Longitude lines. They are also called meridians.
-- The Prime Meridian. -- 180° longitude
Since the earth is a sphere (ball), you can reach any place on earth by traveling in either direction from any other place. To reach any west longitude from the Prime Meridian, heading west is the shorter way. To reach any east longitude from the Prime Meridian, heading east is the shorter way.
Longitude measures the distance east and west of the Prime Meridian, which is the imaginary line that runs from the North Pole to the South Pole through Greenwich, England.
Longitude is measured in degrees east or west.
Longitude