Grade 7 Social Studies NATURAL AND HISTORIC BUILT ENVIRONMENTS IN AFRICA – Maps and mapwork Notes
MAPS AND MAPWORK
A map is a representation of the earth or part of it on a flat surface.
Position of Africa
- Africa lies between latitude 37ºN and 35ºS and on longitude 18ºW and 52ºE.
- Separated by water from all other continent except at the point where it joins Asia.
- Mostly Easterly point is called ras hafun(cape guardafui)
- Mostly westerly is cape verde
- Mostly northerly is cape bon
- Mostly southerly is cape agulhas
- Africa is connected to sinai peninsula by suez canal
- Separated from Spain by strait of Gibraltar
- Separated from Arabia by strait of bab el-mandeb
Shape of Africa
The northern half is very wide while the southern is much narrower
At the cape guardafui extends outwards in the shape of a horn therefore the horn of Africa
Size of Africa
Africa is the second largest continent in the world
Has an area of about 30.3 million square kilometres (20% of the total land surface)
It measures 8000 km from north to south and 7400km from east to west
Other continents
Shape of Africa
The northern half is very wide while the southern is much narrower
At the cape guardafui extends outwards in the shape of a horn therefore the horn of Africa
Size of Africa
Africa is the second largest continent in the world
Has an area of about 30.3 million square kilometres (20% of the total land surface)
It measures 8000 km from north to south and 7400km from east to west
Other continents
- Asia – 43608000km2
- Africa – 30335000km2
- North America – 25349000km2
- South America – 17611000km2
- Antarctica – 13340000km2
- Europe – 10498000km2
- Australia – 8923000km2
Countries that makes up the Africa continent
Africa has the largest number of countries in the world making o total of 55 countries
- Algeria 2381741km2
- Angola 1246700km2
- Benin 115773km2
- Botswana 600372km2
- Burkina Faso 274200km2
- Burundi 28490km2
- Cameroon 475900km2
- Cape Verde 7275km2
- Central Africa republic 622984km2
- Chad 1284000km2
- Comoros 2117km2
- Congo 34965km2
- Cόte d’ Ivoire 322463km2
- Djibouti 23310km2
- DR Congo 2345409km2
- Egypt 1101449km2
- Equatorial guinea 28051km2
- Eritrea 124320km2
- Ethiopia 1221900km2
- Gabon 267667km2
- Gambia 11369km2
- Ghana 238537km2
- Guinea 245957km2
- Guinea bisau 36125km2
- Kenya 582648km2
- Lesotho 30460km2
- Liberia 111369km2
- Libya 1775000km2
- Madagascar 592900km2
- Malawi 118484km2
- Mali 1240192km2
- Mauritania 1030700km2
- Mauritius 2040km2
- Morocco 724730km2
- Mozambique 802000km2
- Niger 1267000km2
- Namibia 824295km2
- Nigeria 923773km2
- Rwanda 26338km2
- Sӑo Tome & principe 964km2
- Senegal 196192km2
- Seychelles 453km2
- Sierra Leone 72325km2
- Somalia 626541km2
- South Africa 1221037km2
- South Sudan 644329km2
- Sudan 1886068km2
- Eswatini 17368km2
- Tanzania 947419km2
- Togo 56785km2
- Tunisia 164154km2
- Uganda 236036km2
- Western Sahara 252120km2
- Zambia 752618km2
- Zimbabwe 390759km2
The largest country in Africa is Algeria while the smallest is Seychelles.
Offshore island also form part of Africa;
- Seychelles
- Sao Tome and Principe
- Mauritius
- Comoros
- Madagascar
- Cape Verde
Locating places and features on a map using latitudes and longitudes
- When giving the position of a place or features we with start with the latitude and then longitude
Major latitudes and longitudes
- Major longitude is called prime meridian also called Greenwich meridian
- In Africa it passes through:
- Ghana(Accra)
- Algeria
- Burkina Faso
- Mali
- All other longitudes are measured and named from prime meridian up to 180 ̊ on both sides
- Major latitude are 3 passing through Africa
- Equator 0 ̊ – divides Africa into two parts
It passes through;
- Gabon
- Congo
- DR Congo
- Uganda
- Kenya
- Somalia
- Tropic of cancer 231/2 ̊ north of equator
It passes through;
- Western Sahara
- Mali
- Mauritania
- Algeria
- Libya
- Egypt
- Tropic of Capricorn 231/2 ̊ south of equator
It passes through:
- Namibia
- Botswana
- South Africa
- Mozambique
- Madagascar
- Other important lines of latitude are far from Africa are:
- Arctic circle 661/2 ̊N
- Antarctic circle 661/2 ̊S
Calculating the time of different places in the world using longitudes
- Rotation of the earth- This is movement of earth on its own axis
- Distance between longitudes is measured in degrees
- There are 360 meridians or longitudes
- One complete rotation is 360 ̊
- The direction of the rotation is from west to east i.e. anticlockwise direction.
- One complete rotation takes 24 hours
- All places found in the east of the Greenwich meridian will see sunrise first and therefore they are one hour ahead of those to the west
Effects of rotation of the earth
- Differences in time along different longitudes
- Occurrence of day and night
24hrs = 360 ̊
1hr = ?
360×1 ÷24 =15
Therefore 1hr =15 ̊ or 360 ̊= (24×60)minutes=1440min
̊= 1440÷360 ×1=4min
I Hr the earth covers 15º and 1º it covers 4 minutes
Calculating time of places found to the east of Greenwich Meridian
Example 1
The time in Accra 0 ̊ is 7.00am.calculate time in bermbera 45 ̊E
1hr =15 ̊
? = 45 ̊ = 45÷15×1 =3hrs
So 3hrs is equivalent to 45 ̊ then add 3hrs to 7.00am to get 10.00am
Example 2
Suppose the time at GWM is 12 noon what is the local time at Watamu 40◦E?
Time gained=40×4=160min=2 hours 40min
Local time at Watamu is 12.00+2.40=14.40-1200=2.40pm.
Example 3
At Dar-es-Salaam 40◦E time is 12pm what is the time at Ecuador 40◦E?
40◦+20◦=60◦
60×4=240min=4hours
Ecuador is behind in time =12.00-4=8 am.
NB
- When calculating time to the east of Greenwich meridian, we add the time difference to the local time.
Calculating time of places found to the west of Greenwich Meridian
- When calculating time to the west of Greenwich meridian we subtract the time difference to the local time
Example 1
A plane leaves off in New York, 74ºW at 7 am local time. What is the local time in Stockholm 18ºE
NB
- If the places are on the same side subtract the degrees to get the difference and add or subtract from the reference time depending on which side the place is.
Pictures, plan and maps
| Picture | Plan | Maps |
| Image of a real object | Outline of something drawn to scale | Representation of the whole or part of the earth’s surface drawn to scale |
| Gives details in their visible shapes and sizes | Also drawn as if a person was directly above the ground | Shows outline of objects on the ground |
| Can be inform of free hand, drawing, painting or a photograph | It represents a very small place | Drawn as if the drawer was above the ground |
| Not drawn to scale | The scale is large to show details e.g. house plan | It shows details |
| Gives specific information | Most of the features are indicated by symbols. |
Types of maps
- Topographical maps
This shows selected natural physical features on a small portion of a country.
- Atlas map this is a collection of maps in one volume
- Sketch map maps which are roughly drawn.
A good sketch map should have the following characteristics:
- Neat and clear
- Title
- Frame
- Key
- Compass direction
Importance of maps in day to day lives
- Sketch maps are used to summaries information for easy reference.
- Used for locating other countries.
- Used for comparing sizes of countries.
- For locating climatic regions of different parts of the world.
- Give information on distribution of geographical phenomena e.g. vegetation on the earth’s surface.
- Help travelers to find their way.
- Used to calculate distance of a certain place.
- Used to locate physical features like land forms.