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As it is known the Earth`s surface is very large and diverse, that’s
why it’s always important to be able to find the place or destination
you need. In order to identify the exact location of places on Earth we
can use series of imaginary vertical and horizontal lines – parallels

and meridians that form the system of geographical coordinates. The
geographical coordinate system measures location from only two
values, which are both measured relative to the polar axis of the Earth.

These two measures used in the geographic coordinate system are
called latitude and longitude.

Figure 3.1. Parallels and meridians

Latitude (shown as a horizontal line) is the angular distance in
degrees, minutes and seconds of a point north or south of the Equator.

Lines of latitude are often referred to as parallels. Latitude measures
the north-south position of locations on the Earth's surface relative to a
point found at the center of the Earth. This central point is also located
on the Earth's rotational or polar axis.

Longitude (shown as a vertical line) is the angular distance, in
degrees, minutes, and seconds, of a point east or west of the Prime
(Greenwich) Meridian. Lines of longitude are often referred to as

meridians. Longitude measures the west-east position of locations on
the Earth’s surface relative to a circular arc called the Prime Meridian.
The prime meridian is the line of 0 longitude, the starting point for

measuring distance both east and west around the Earth. The prime
meridian is arbitrary, meaning it could be chosen to be anywhere. Any
line of longitude (a meridian) can serve as the 0 longitude line.

However, there is an international agreement that the meridian that
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