How many parallels are there?

The geographical coordinate system made up of many circles of latitude and longitude ensures that there is an exact location for every point on earth. It is imaginary coordinates on the earth's surface that make this possible. This network of latitude and longitude is briefly described here.

There is an equator and a prime meridian as a starting point

• Imagine the earth as a sphere and lay lines over it, but not criss-cross, but according to set rules. There is a line that divides the sphere in exactly two halves. Transferred to earth, this line is exactly the equator. It divides the earth into a northern and a southern hemisphere.
• The equator is the parallel of the largest spherical circle on earth. This circle is equidistant from the North Pole and the South Pole. Its length is around 40,075 kilometers. Parallel to the equator there are now many parallels, which are determined according to precise rules.
  instagram viewer
• Now put in the angle of exactly 90 degrees (i.e. at right angles to the circles of latitude) further lines over the sphere. These lines run through the poles, i.e. through the south and north poles of the earth. They are the longitudes of the geographic coordinate system. They are also known as meridians. One of these longitudes is defined as the so-called prime meridian.

Many parallels divide in north-south direction

• Even though there are many parallels, it is easy to determine a starting point for the coordinate system here. The latitude of zero degrees is assigned to the largest circle, i.e. the equator.


Graticule - this is how you calculate distances

The position of a point or place on the earth's surface is indicated in the graticule by its ...

• Now further parallels to the north or south always follow at a distance of 111 kilometers. How many parallels are there now? The answer is: Each hemisphere has 90 parallels.
• The latitude is given in degrees, minutes and seconds. As with the time, a degree has 60 minutes and a minute has 60 seconds. On the equator and on the meridians, one minute is exactly the length of a nautical mile of 1852 meters. For the many other parallels, this dimension is calculated differently by a certain factor.
• Now you still have to pay attention to whether the latitude is north or south.
• For example, one speaks of 50 degrees north latitude. Frankfurt am Main is located on this parallel. The city of Santa Cruz in Argentina is located on the parallel of 50 degrees south latitude.

Meridians define the east-west position

• Half a longitude, always from the north to the south pole, is a meridian, with the help of which the position of a place in east-west direction can be determined. The lines across the earth at right angles to the circles of latitude are all of the same length. Therefore a longitude had to be determined from which to count.
• In 1884 an international conference established the longitude as the prime meridian, which runs through the observatory in London Greenwich. It is also known as the Greenwich Meridian. From here, 360 degrees to the east are counted or 180 degrees to the east or 180 degrees to the west.
• The system described here, in which there are 180 circles of latitude and 360 circles of longitude, is shown in a simplified manner. For exact location determination it must be noted that the earth is not a real sphere, but is slightly elliptical in shape. Nevertheless, the geographic coordinate system has proven its worth for location determination.