Latitude and longitude

Latitude and longitude form the geographic coordinate system used to specify any location on the Earth's surface. Latitude measures angular distance north or south of the equator, the imaginary circle that lies midway between the poles and divides the globe into the Northern and Southern Hemispheres. Lines of equal latitude, called parallels, run east–west and range from 0° at the equator to 90° at the North and South Poles. Longitude measures angular distance east or west of a reference line called the prime meridian, which by international agreement passes through Greenwich, near London.

Lines of longitude, called meridians, run north–south from pole to pole and converge at each pole. They range from 0° at the prime meridian to 180°, where the line approximately corresponds to the International Date Line. A coordinate pair therefore pins down a point as so many degrees of latitude combined with so many degrees of longitude, with each degree subdivided into 60 minutes and each minute into 60 seconds, or expressed as a decimal fraction.

Because the Earth rotates 360° in roughly 24 hours, every 15° of longitude corresponds to about one hour of time difference, which is the basis of the world's time zones. Interactive mapping tools let users enter coordinates to find a place, or click a location to read off its latitude and longitude, and many link these positions to gazetteers of geographic names and city databases.

Frequently asked questions

What is the difference between latitude and longitude?

Latitude gives the north–south position relative to the equator; longitude gives the east–west position relative to the prime meridian at Greenwich.

Where is zero degrees longitude?

At the prime meridian, which by convention runs through Greenwich. Zero degrees latitude is the equator.

How are coordinates linked to time zones?

The Earth turns 15° of longitude per hour, so longitude is the foundation of the global system of time zones, although actual zone boundaries follow political borders.