Getting Started B: Latitude and Longitude

People pinpoint places on the Earth using a pair of coordinates known as latitude and longitude. Latitude describes a location’s distance from the Equator. Longitude describes its relative distance east or west of a north-south band called the prime meridian, which runs through Greenwich, England. The latitude and longitude of any place on Earth’s surface define its unique global address.

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 Latitude and Longitude

Latitude measures distance north or south of the Equator (the band of 0 degrees latitude that runs east and west around the middle of the Earth). Each latitude line forms an imaginary circle around the Earth. Because these circles are parallel to the Equator, they are sometimes called parallels. The farther the circles are from the Equator, the smaller they are, until they become points at the North and South Poles. The latitude of the North Pole is 90 degrees north, and that of the South Pole is 90 degrees south. A location’s latitude is measured in degrees. If you could draw one line from the location to the center of the Earth and a second line from the Equator to the center of the Earth, the angle between those lines would equal the latitude of the location.

Longitude measures distance east or west of an imaginary band running from the North Pole through Greenwich, England, to the South Pole. This imaginary band defines 0 degrees longitude and is called the prime meridian. Other longitude lines are sometimes referred to as meridians. All longitude lines meet at the North and South Poles.

Maps are often marked with both parallels and meridians—latitude and longitude lines. The latitude and longitude of a location are its geographic coordinates. NGS Kids Network refers to these coordinates of a place as its global address. If you know the coordinates, or global address, you can use a world map to locate any point on Earth.

Today, navigators in airplanes, on ships, and even cars can locate their positions on a map by using a global positioning system (GPS) receiver. This device receives signals from a network of satellites in fixed orbits above the Earth and then calculates its own location by a process called triangulation. Based on the signals from three satellites, a GPS device can determine latitude and longitude; with a fourth signal, it can also determine elevation. Some airplanes can actually “fly by wire,” navigating solely via GPS satellites for hours at a time. Perhaps one day the GPS network will drive buses to and from school!

 Latitude and Temperature

Latitude and temperature are related. In general, as latitude increases (that is, as the numbers used to define a location’s latitude get larger), air temperature gets colder. This is true as you travel either north or south of the Equator. Other factors, such as elevation and being downwind of large bodies of water, can also have a large effect on a place’s average temperature. But latitude is extremely important in determining whether most places are warm or cold. Latitude is also important in determining temperature over the course of the seasons each year, since when places at northern latitudes are experiencing summer, those at southern latitudes are experiencing winter.

The temperature map below illustrates that places closer to the Equator (lower latitudes) are warmer in general than places farther from the Equator (higher latitudes).

 Original map provided by the U.S. National Oceanic and Atmospheric Administration—Cooperative Institute for Research in Environmental Sciences Climate Diagnostics Center, Boulder, Colorado

Latitude and Temperature North of the Equator

In general, places at high latitudes are colder than places at low latitudes. So if you know the latitudes of several places, you can make an educated guess about which location is colder than another. Review this map of temperatures in the Northern Hemisphere (that is, the half of Earth that is north of the Equator):

 Original map provided by the National Oceanic and Atmospheric Administration-Cooperative Institute for Research in Environmental Sciences Climate Diagnostics Center, Boulder, Colorado

Are the locations farthest from the Equator the coldest today? Click on the white dots on the map or follow the links below to find out.

Record your prediction of the temperature in each location and then check the actual temperature. Record the results and compare.

Libreville, Gabon 0° N, 9° E
Houston, U.S.A. 29° N, 95° W
Harbin, China 45° N, 126° E
Narvik, Norway 68° N, 17° E
Alberta, Canada 82° N, 62° W

You can see these places, or locations near them, live at the using this world wide web site.

Latitude and Temperature South of the Equator

Review this map of temperatures in the Southern Hemisphere (that is, the half of Earth that is south of the Equator):

 Original map provided by the National Oceanic and Atmospheric Administration-Cooperative Institute for Research in Environmental Sciences Climate Diagnostics Center, Boulder, Colorado

Are the locations farthest from the Equator the coldest today? Click on the white dots on the map or follow the links below to find out.

Record your prediction of the temperature in each location and then check the actual temperature. Record the results and compare.

Belem, Brazil 1° S, 48° W
Darwin, Australia 12° S, 130° E
Punta Arenas, Chile 53° S, 70° W
Vostok, (Russia) Antarctica 80° S, 102° W

You can see these places, or locations near them, using this world wide web site.

 Quiz Yourself

Ready to see what you learned? Then give this short quiz a try.

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