Skip to content Skip to navigation Skip to collection information
1. Using lines of longitude and latitude to indicate location
In the same way as we draw lines on a map or plan, imaginary lines are drawn on the earth. Exactly halfway between the north and south poles, we find the EQUATOR. The equator is called the 0° line of latitude, and runs from east to west. Parallel to the 0° line of latitude, we also find a 90°N and a 90°S line of latitude at the two poles.
The equator divides the globe into two halves. The upper half is called the NORTHERN HEMISPHERE and the lower one the SOUTHERN HEMISPHERE.
 |
There are also imaginary lines running from north to south. They are called the lines of longitude. The line of longitude lying on 0° is called the GREENWICH line of longitude. It, in turn, divides the earth into a WESTERN HEMISPHERE and an EASTERN HEMISPHERE. East of the Greenwich line of longitude run 180 lines of longitude, and to the west of it there are also 180 lines of longitude.
All these lines of longitude and latitude form intersections on the earth, with which the exact location of a place can be indicated. More about this later. For now it is enough if you are able to indicate in which hemisphere(s) a place, land or continent is.
Study a map of the world in your atlas and answer the following questions:
2. Location by means of degrees of longitude and latitude
Lines of longitude and latitude
180 ° 160 °W 120°W 80°W 40°W 0° 40°E 80°E 120°E 160°E 180°
 |
3. Lines of latitude
A few important facts:
The best-known one is the equator (0° line of latitude).
The latitude of a place is a good indication of its climate. You know that places near the equator (0°) are normally very hot. You also know that places near the poles (90°) are very cold. Remember that there are more factors than only latitude that influence climate.
The most important lines of latitude
 |
4. Lines of longitude
A few important facts:
Eastern Hemisphere
 |
Western Hemisphere
 |
Use a globe or a map in your atlas and make sure you understand what each of these facts means.
In this way, each line of longitude has an antipode and if the numbers of the two lines’ grades are added together, the answer is always 180°.
But now we have a problem: If we move eastward from the 0° line of longitude and westward from the 0° line of longitude, we reach the 180° line of longitude from both sides. Now our times are going to differ a lot!
It follows the 180° line of longitude, but never cuts across land.
The date east of the IDL is one day earlier;west of the IDL is one day later.
From east to west, you lose a day if you move across the IDL.From west to east, you win a day if you cross the IDL.
The earth revolves from west to east around its own imaginary axis. So the sun rises earlier in places that are nearer to the east.
The sun rises in Durban (31°E) approximately 50 minutes earlier than in Cape Town (18½° E). In South Africa such a difference isn’t a problem, because we use only one time zone (30° E). In a country like the USA, however, it becomes a problem. The sun rises in New York (74°W) approximately three hours earlier than in San Francisco (122½°W). So in the USA you need to have different time zones.
| Learning Outcomes(LOs) |
| LO 1 |
| GEOGRAPHICAL ENQUIRYThe learner will be able to use enquiry skills to investigate geographical and environmental concepts and processes. |
| Assessment standards(AS’s) |
| We know this when the learner: |
|
More about this module: Metadata | Downloads | Version History
This work is licensed by Siyavula Uploaders under a Creative Commons Attribution License (CC-BY 3.0), and is an Open Educational Resource.
Last edited by Siyavula Uploaders on May 1, 2009 4:05 am -0500.