The Geographic Grid

The geographic grid refers to the spherical coordinate system of latitude and longitude used to location positions uniquely anywhere on the surface of the earth. These coordinates are given as angles, rather than distances used in more familiar rectangular coordinate systems. Latitude is the angular distance measured north or south of the Equator from the center of the earth. Latitude values (in degrees) range from 0 at the Equator to 90 North at the North Pole, and 90 South at the South Pole. All latitude lines form complete circles, which are also called parallels. Equator, North Pole, and South Pole are all names of specific parallels of latitude. Latitude is illustrated below.

Longitude lines (also called meridians) are defined as the angle east or west of Greenwich, England (known as the Prime Meridian) from the center of the Earth. Longitude values increase (in degrees) from 0 at Greenwich, England, westward to 180 West and eastward to 180 East as shown in the diagram below. 180 degrees longitude is known as the International Date Line. The International Date Line and the Prime Meridian are both names of specific meridians of longitude. Longitude.

Geographic coordinates, then, are latitude-longitude pairs. The latitude is always given first and the longitude second. Latitude will always include an N (for North of the equator) or S (for South of the equator) and longitude will always include an E (for East of Greenwich) or W (for West of Greenwich).

Use the Coordinate Finder below to practice identifying latitude and longitude for specific places on the Earth's surface. Just drag the cursor across the map.

Identify the latitude and longitude of the center of the following places using the map above (approximately):

Practice finding differences in latitude and longitude between places (use smallest longitude difference):

8. ________ How many degrees latitude difference between Greenwich and Hawaii?
9. ________How many degrees latitude difference between Cape of Good Hope and Siberia?
10. _______How many degrees latitude difference between Amazon and West Antarctic Ice Sheet?
11. _______How many degrees longitude difference between Borneo and Hawaii?
12. _______How many degrees longitude difference between Greenwich and Cape of Good Hope?
13. _______How many degrees latitude difference between Greenwich and West Antarctic Ice Sheet?
14. _______How many degrees longitude difference between Hawaii and Greenwich?
15. _______How many degrees longitude difference between West Antarctic Ice Sheet and Siberia?

Practice finding new latitude and longitudes when moving across the surface of the earth (use the Coordinate Finder above to help get you started):

16. _____ If you start at 30° N and move 20° southward, what is your new latitude?
17. _____ If you start at 60° N and move 25° northward, what is your new latitude?
18. _____ If you start at 50° S and move 60° northward, what is your new latitude?
19. _____ If you start at 30° N and move 100° southward, what is your new latitude?
20. _____ If you start at 20° W and move 50° westward, what is your new longitude?
21. _____ If you start at 150° E and move 30° westward, what is your new longitude?
22. _____ If you start at 30° W and move 40° eastward, what is your new longitude?
23. _____ If you start at 150° W and move 80° westward, what is your new longitude?