Latitude and Longitudes

MEANING OF LATITUDE

Latitude is an angular distance of a point on earth’s surface measured in degrees from the centre of the earth. Latitude is parallel to the equator .Equator divides the earth into two equal halves known as Northern & southern hemisphere. Lines of latitude are sometimes called parallel of latitude.

IMPORTANT LINES OF LATITUDE

i. The equator 0° (ii) North pole  90°N  (iii) South pole 90°S   (iv) The tropic of Cancer  23 ^1/2°N  (v) Tropic of Capricorn  23 1/2°S  (vi) Arctic circle  66 1/2°N  (vii)  Antarctic circle 66 1/2°S .

USES OF LINES OF LATITUDES

1. The lines of latitude are used to determine the exact location of a place on the         atlas map.
2. They are used to calculate the distance between two places on the earth surface.

LONGITUDE

Longitude is an angular distance measured in degree east and west of the Greenwich Meridian. It is an imaginary line drawn on the globe (earth) running from north to south at right angle to the parallels.

The longitude passing through London and Accra is called the Great, Prime or Greenwich meridian and it is on longitude 0°.  All longitudes are called meridian.

IMPORTANT LINES OF LONGITUDE

Long  0° (Prime Meridian) , long  45°E  , long 45°W  long 90°E long 90°W  long180°E etc.

USES OF LINES OF LONGITUDE

1. They are used to calculate local time.
2. They are used to determine the exact location of places on the atlas map.

Similarities between  Lines of Latitudes and Meridians

1. Both are used for location of places on the map.
2. Both are numbered in degrees.
3. Both are imaginary lines drawn on the globe.
4. Both contain great circles.

EVALUATION QUESTIONS

1.  What is latitude?

2. Mention the important lines of latitude and longitude

Differences between Lines of Longitude and Lines of Latitudes

Lines of latitudes	Lines of longitudes
Equator is the only great circle	It has many great circles as opposite parts of lines make a great circle.
Lines are shorter towards the pole	Lines are of the same length.
They run from West to East	They run from North to South.
Lines are parallel to each other	Lines are not  parallel  to each other but converge at the poles.
Lines are used for measuring distance	Lines are used for calculating local time.
Has the equator as its reference point	Has Greenwich meridian as its reference point.
Latitude measures up to 180° i.e 90°N – 90°S	Longitudes measures up to 360° i.e 180°W – 180°E.
The lines are called parallels	The lines are called meridians.

GREAT CIRCLE AND SMALL CIRCLE

A great circle is any line that divides the earth into two equal halves or hemispheres. The centre of the great circle is also the centre of the earth.

Two opposite lines of longitude make a great circle e.g long 0°, 180°W and 180°E, long.30⁰W and long15°W, long110°W and 70°E, etc .

On the other hand, a small circle is any line that does not divide the earth into two equal halves or hemisphere. All lines of latitude are small circles except the Equator. Examples are lat.90°N, 90°S, Tropic of cancer, Tropic of Capricorn etc.

EVALUATION QUESTIONS

1. Differentiate between lines of latitude and lines of longitude.
2. Describe a great circle.

GENERAL EVALUATION

1. Mention two uses of lines of latitude and longitude.
2.  State two similarities and four differences between longitude and latitude.
3.  Describe a small circle.
4. What is a great circle?

READING ASSIGNMENT

Essential Geography, O.A. Iwena, Pages 14-17.

WEEKEND ASSIGNMENT

1. 1. Lines of  longitude can best be described as (a) The angular distance of a place north or south of the equator (b) semi circle on the     globe (c) imaginary lines on the earth’s surface joining the north and south poles
2. The angular distance of a point on the earth’s surface measured in degrees from the centre of the earth is known as (a) latitude (b) longitude (c) international date line
3. The shortest flying route between any two points on the earth surface lies along the (a) Tropic of Capricorn (b) Tropic of Cancer (c) Great circle
4. A great circle can be described as (a) a line of longitude (b) the line of  latitude  (c) a shortest distance between two points on the globe
5. The following are the similarities between lines of longitude and latitude except (a) both are used to calculate local time of a place (b) both are numbered in degree (c) both     contain great circles

THEORY

1. State two differences between longitude and latitude.

List five important lines of latitude.