Lines of longitude are imaginary lines running from pole to pole. with the Prime Meridian (zero longitude) running through the Greenwich Observatory, London, England.
Lines of latitude are lines circling the globe parallel to the Equator.
Longitude and latitude (plus minutes and seconds of degrees) allow any position on the world to be pin-pointed.
Latitude and longitude form an (imaginary) grid of lines on the Earth's surface, and enable the identification of any point by its geographic coordinates.
Latitude lines are circles around the globe connecting points that are the same distance from the equator (which is a latitude line itself, 0°) Longitude lines connect the North Pole to the South Pole, and represent distance from an arbitrary line called the Prime Meridian. They are used to determine a location's position measured around the globe east or west. The degrees represent an angle from the plane of the equator.
Longitude lines mark angles east and west of the arbitrary Prime Meridian, that runs through Greenwich, England. They converge at the poles and are closer together the closer one gets to a pole.
Latitude lines (called parallels, because they are parallel on globes) are formed from points on a circle around the globe, equidistant from the midline (the equator) and expressed as angles from the equator (i.e. a line from the Earth's center to a corresponding point on the equator). Latitude lines are parallel to the equator, and each 1° difference is the same distance (about 111 km or 69 miles).
Longitude lines (meridians) represent the division of the (nominally) spherical Earth into its component 360 degrees of arc. Longitude lines intersect at each pole, and the distance between lines is greatest at the equator (where it is approximately equal to a degree of latitude). They are numbered as degrees east or west of an arbitrary meridian, which is set at Greenwich, England, and longitudes can number up to 180° E or W (where they are the same, at approximately the International Date Line).