Longitude is the angle along the Earth's surface between the Prime Meridian and any point on the surface.
The 'lines' don't need to be measured.
prime meridian
The imaginary line is called the Prime Meridian.
Lines of Latitude
The imaginary lines that run east to west.
The Prime Meridian is an imaginary line from which angles east and west are measured in order to help define and describe locations. The angle thus measured is called the location's 'longitude'.
East and west distances can be measured using longitude lines, imaginary lines that connect the Earth's poles. The distance between any two longitudes is the greatest at the equator, and zero at the poles.
The imaginary lines that run around the earth in an east-west direction are lines of latitude or parallels.
They are drawn on the earth as imaginary lines that run from east to west.
Lines of longitude are imaginary lines running from the North to the South Poles of the Earth. They are often referred to as Meridians. They are measured in terms of the angular distance east or west from the prime Meridian which runs through Greenwich, England.
Lines of Latitude
Latitude lines, longitude lines run north south
latitude