For those of us with no real navigation experience, encountering longitude and latitude coordinates is usually the result of some hiccup using Google Maps. 40.722272, -73.994194?

Longitude Lines of longitude run from the top of the Earth to the bottom. They are not parallel as lines of latitude are - they meet at a point at the north and south poles and are called meridians.

The globe shows the lines of latitude and the degrees of north and south. The line labelled 0° longitude is called the Prime Meridian or the Greenwich Meridian and runs through London.