This is the coordinate system you may be most familiar with. It is a geographic system and can be used to locate a position on the Earth's surface. 

Latitude tells us how far north or south a point on the Earth is. Longitude tells us how far west or east a location is. They are both angles and are measured in degrees. A line on a map that connects points with equal longitude or latitude is called a meridian. 

The Earth's equator has a latitude of 0°. There are 180° degrees of latitude. These range from 90° South at the South Pole to 90° North at the North Pole.

The Greenwich Meridian, which runs through the Royal Observatory Greenwich in London, is the prime meridian, where the longitude is 0°. Because the Earth is a sphere, there are 360 degrees of longitude. These range from 180° East to 180° West.

We can describe the location of anywhere in the world using latitude and longitude. For example, the centre of Liverpool has a latitude of 53.3° North and a longitude of 2.8° West. We can write this as 53.3°N, 2.8°W.