The meridians are imaginary semicircular lines that go through the North and South poles. They are used to measure the longitude of a point on Earth, with respect to the 0 meridian, or Greenwich meridian.
They are lines formed by man, with an East-West direction, each of these lines is numbered, from 0º, which is the equator or equatorial line (the only line that is a circle in strict terms, and that crosses the center of the terrestrial globe), up to 90º at the North Pole and the South Pole.
The equator, or parallel 0º, divides the planet into two hemispheres: North and South. It is finished by 4 other main parallels, with which a distinction is made since they correspond to a specific position of the Earth, with respect to its orbit of the Sun:
- Arctic Circle: It is the northernmost parallel. This parallel is the zone in which the polar night (December) and the midnight sun (June) of the Northern Hemisphere occur.
- Tropic of Cancer: it is the northernmost parallel, characterized because it is the place where the Sun reaches the zenith, during the June solstice.
- Tropic of Capricorn: it is the southernmost parallel in which the Sun reaches the zenith, during the December solstice.
- Antarctic Polar Circle: it is the southernmost parallel, where the polar night (June) and the midnight sun (December) of the Southern Hemisphere occur.
They are imaginary lines, which go from the North Pole to the South Pole, so they have the shape of semicircles. They divide the Earth into two hemispheres: Eastern and Western.
Main meridians There are 360 meridians: 180 to the west and 180 to the east of the zero meridian. The main ones are the following:
- Greenwich Meridian: It is named in honor of the contributions of the Greenwich Observatory in London. In addition, said parallel “passes” through the location of said observatory. It is also known as the 0 meridian.
- Antimeridian: so called because it opposes the Greenwich meridian, forming an angle of 180 degrees with respect to the 0º meridian. It is also known as the 180 meridian.
Since 1884, the 0º meridian has been used to establish world time zones. From it, and towards the East, the hour increases, and towards the West, it decreases.
For its part, the antimeridian is the reference point for the international date line.
The distance of any point on the planet with respect to the 0º meridian, either to the East or to the West, is known as longitude.
Parallels and Meridians
|Definition||Lines implanted by man for geographical purposes. They are circular in shape and are perpendicular to the earth’s axis.||Lines established by man for geographical purposes. They have a semi-circular shape and cross the Earth at its poles.|
|Characteristics||· They divide the Earth into two hemispheres: north and south.
The reference line is the 0º parallel
· The last parallel is 90º.
· They serve as a reference to locate positions on the Earth.
· They allow to calculate the latitude.
|· They divide the Earth into two hemispheres: Eastern and Western.
The reference line is the 0 meridian
· The last meridian is 180, or antimeridian.
· They are time zone references.
· They allow to calculate the length.
|Points of reference||Ecuador||Greenwich Meridian|