Latitude and Longitude

Introduction

In the Junior School CBC (KICD), Social Studies teaches learners to locate places on the globe. Two sets of imaginary lines form a grid that gives every place an address.

Latitude

Lines of latitude (parallels) run east to west and measure distance north or south of the Equator.

• Equator: 0 degrees.
• North Pole: 90 degrees N; South Pole: 90 degrees S.
• Tropic of Cancer: 23.5 degrees N.
• Tropic of Capricorn: 23.5 degrees S. Nairobi is about 1 degree S, almost on the Equator.

Longitude

Lines of longitude (meridians) run from pole to pole and measure distance east or west of the Prime Meridian (0 degrees), which passes through Greenwich, England. The range is 0 to 180 degrees E and W. Nairobi lies at about 37 degrees E.

Giving a location

Write latitude first, then longitude: Nairobi is about 1 degree S, 37 degrees E.

Longitude and time

The earth rotates 360 degrees in 24 hours, so 15 degrees per hour, or 1 degree every 4 minutes. Places east of Greenwich are ahead in time; places west are behind.

Worked example: Kenya's standard time is based on 45 degrees E. Difference from Greenwich = 45 / 15 = 3 hours. When it is 12:00 noon at Greenwich, it is 3:00 pm in Kenya.

Uses

• Navigation by ships and aircraft.
• Locating places on maps and GPS.
• Working out time differences for travel and communication.

Try it

• State the latitude of the Equator and the Tropics.
• Find a place 30 degrees east of Greenwich. How far ahead in time is it?
• When it is 6:00 am at Greenwich, what time is it in Kenya?