A system of angles measured from the centre of the Earth is used to describe any position on the surface of the Earth. These are known as latitude and longitude.
Latitudes are measured from the centre of the Earth to the north or south of the equator. They extend from the equator, which is at 0°, to the north and south poles, which are at 90°N and 90°S. Each line of latitude is parallel to the equator.
The equator itself is also a line of latitude (0°).
Longitudes are measured from the centre of the Earth to the east and west, with the prime meridian (or Greenwich meridian) being 0°. The lines of longitude then continue on either side of the prime meridian to 180°E and 180°W.
When all the lines of latitude and longitude are drawn on the Earth’s surface, it creates a ‘grid’ that can be used to describe any position on Earth. To more accurately describe a position, the degrees are divided into minutes and seconds.
A given position is then described by its latitude and longitude, known as coordinates. The latitude is written first and the longitude second, for example:
This is read as “54 degrees 35 minutes 49 seconds North, 2 degrees 12 minutes 58 seconds West“