On this page you will find CLIMATE AND WEATHER GRADE 12 NOTES – GEOGRAPHY STUDY GUIDES

This chapter covers secondary (regional) and tertiary (local) circulations or weather patterns. This knowledge will enable you to analyse weather patterns and the microclimate of cities and valleys in the exam.
Key concepts
If you know and understand the definitions in this chapter, you will be able to answer most of the questions in the climate and weather (climatology) section of the final exam. Use your mobile notes to learn these concepts well (see page x for instructions on how to make them). Adding pictures to your mobile notes will help you remember the concepts.

1.1 Introduction

Our focus will be on the South African climate, mid-latitude cyclones, tropical cyclones, sub-tropical anticyclones and local climate (valley and city climate). But first we need to understand synoptic weather charts (maps), and satellite images.
1.1.1 Synoptic weather map interpretation
To better understand weather patterns and weather phenomena you need to be able to interpret the synoptic weather map. A synoptic weather map shows weather conditions and phenomena (temperature, precipitation, wind speed and direction, atmospheric pressure and cloud coverage) over a wide area at a given time based on worldwide observations recorded at the same time (from weather stations, airplanes, weather balloons and satellites).
On a synoptic weather map there are lines called isobars:

• These lines join points of equal pressure (all along one isobar the pressure is the same).
• The pressure is measured in hectopascals (hpa)/millibars (mb).
• The isobars form patterns (shapes formed by many isobars).
  Figures 1.1.1A shows a low pressure and high pressure cell

Synoptic weather maps are very often tested in the exam.

Note that the pressure reading decreases towards the centre of a Low and increases towards the centre of a High.
Figure 1.1.1C on page 4 shows a simple weather station. It describes the weather of a particular place that is found on a synoptic weather map. In the exam, you may be asked to describe the weather of a particular place on the synoptic weather map by referring to the weather station. You will need to comment on the following weather elements:

• Cloud cover
• Wind direction
• Wind speed
• Air temperature
• Dew point temperature
• Precipitation (any form of water falling from the sky, e.g. rain, hail, snow and ice)

When answering questions based on a synoptic weather chart in the exam, you will be given either a summer synoptic chart (see Figure 1.1.1E) or a winter synoptic chart (see Figure 1.1.1F).

Remember your compass points to determine wind direction.
Make sure you know the weather symbols shown in Figure 1.1.1D (right). They will help you to write this type of question.
Summer synoptic chart
Figure 1.1.1E shows a typical summer synoptic weather chart of South Africa. The features of a summer synoptic chart to note are:

1. Tropical cyclone (look for the symbol on the synoptic chart)
2. Low pressure over the land (see the low pressure cell in Figure 1.1.1E)
3. The date
4. South Indian high pressure found south east of South Africa is further south (see the high pressure cell in Figure 1.1.1E)
5. Generally high temperatures over the land

Make sure you know which features to look out for on the chart you are given.
Winter synoptic weather chart
Figure 1.1.1F shows a typical winter synoptic weather chart of South Africa.
The features of a winter synoptic weather chart to note are:

1. Cold fronts moving over the land
2. Dominant Kalahari high pressure over the land (look for a large high pressure cell over the land)
3. The date
4. South Indian high pressure and the South Atlantic high pressure are closer to the land and further north
5. Generally low temperatures over the land

1.1.2 Global air circulation
These are winds that cover large areas over the Earth’s surface. There are three global wind systems:

• The tropical easterlies
• The westerlies
• The polar easterlies

A force called Coriolis force causes global winds to move to the left in the southern hemisphere and to the right in the northern hemisphere.
The tri-cellular arrangement, the pressure belts and the global winds together form the global air circulation. This is shown in Figure 1.1.2 below.
Learn to redraw Figure 1.1.2 and label it from memory.

1.2 Cyclones

1.2.1 Mid-latitude cyclones
In this section, we look at mid-latitude cyclones in more detail. We will focus on the cross-section through a mature mid-latitude cyclone and the weather that occurs as a result of the cold front. This is the most frequently tested section as South Africa is mostly affected by the passage of cold fronts.
Figure 1.2.1A shows a cross-section through a mid-latitude cyclone. You must be able to label and sketch the cross-section from a synoptic view, as shown in Figure 1.2.3A (see page 10, table 1.1).

Learn to redraw Figure 1.2.1A and label it. You must be able to describe the weather that occurs with a mid-latitude cyclone.
As a mid-latitude cyclone moves towards South Africa, it is the cold front that mostly affects our weather (see Figure 1.2.1C on page 8).

Weather in front of the cold front (see point 1 in Figure 1.2.1A above):

• Cool temperatures
• Very low pressure
• Overcast conditions, cumulonimbus clouds
• Thunderstorms

Weather behind the cold front (see point 2 in Figure 1.2.1A above):

• Cold temperatures
• High pressure
• Partly cloudy conditions, cumulus clouds
• Light rain

Note that as a mid-latitude cyclone moves from west to east, we experience the warm air mass in front of the cold front first, then the air behind the cold front. This can be seen in Figure 1.2.1A (above) as you move over from point 1 to 2.
Figure 1.2.1B (below) shows the weather conditions before and after the cold front.

1.2.2 Tropical cyclones
A tropical cyclone is a type of low pressure system which generally forms in the tropics (between 5°C and 30°C North and South). It is accompanied by thunderstorms and a circulation of winds near the Earth’s surface, which is clockwise in the southern hemisphere and counter-clockwise in the northern hemisphere. Tropical cyclones are also known as hurricanes in America; typhoons in China and Japan; and willywillies in Australia. Tropical cyclones are given names alphabetically within the season in which they occured. For example, ‘Alfred’ will denote that it is the first tropical cyclone to occur in that season.
We will now look at tropical cyclones in more detail by focusing on the cross-section through a mature tropical cyclone.

In order for the tropical cyclone to occur there should be:

• temperature of 27°C and more
• Coriolis force
• enough moisture
• less function

Figure 1.2.2A shows a crosssection through a tropical cyclone. You must be able to label and sketch the cross-section from a synoptic view as shown in Figure 1.2.3A (see page 10, table 1.1).

Make sure you are able to draw Figure
1.2.2A and label it correctly.
1.2.3 Characteristics of mid-latitude cyclones and tropical cyclones

Table 1.1 compares the characteristics of mid-latitude cyclones and tropical cyclones.

	CHARACTERISTICS
	Mid-latitude cyclone	Tropical cyclone
Other names	Frontal depression, temperate cyclone, extra tropical cyclone	Hurricane, typhoon, Willywillies (named alphabetically at the beginning of each season)
Formation	40–60o N and S	around 5o N and S
Occurrence	30–60o N and S	Over tropical oceans 5–30o N and S
Movement	West to east (driven/pushed by Westerlies)	East to west (driven/pushed by Easterlies)
Season	All year round in both hemispheres; affects South Africa in winter	Mid- to late summer, early autumn
Identifying features	Warm front, warm sector, cold front, cold sector	Stormy weather in the vortex; the eye is a calm, intense low pressure area
Weather	Weather associated with a cold front: overcast, low temperatures, strong winds, heavy rain	Warm to hot, violent winds; intense thunderstorm activity
Areas affected	Western side of continents in mid-latitudes	Eastern side of continents in tropical latitudes
Synoptic representation of the cyclones on a weather map

You must know the characteristics of each cyclone. In the exam these characteristics are typically asked in one of three ways:

1.3 Factors affecting the South African climate

There are three factors that have the greatest impact on South Africa’s climate:

• South Africa is surrounded by oceans and ocean currents.
• South Africa is mostly found on a plateau.
• South Africa is affected by the subtropical high pressure belt.

These three factors cause the typical weather we experience in each season. Let us look at each factor in more detail.
1.3.1 The impact of the ocean and the ocean currents on South Africa’s climate
Much of South Africa is surrounded by oceans. The oceans affect the temperature at the coast and inland as follows:

• Water heats up slowly and cools down slowly.
• This moderates temperatures along the coastline (i.e. the minimum and maximum temperatures are not very far apart) – also known as maritime.
• This causes temperatures inland to be extreme (i.e. the minimum and maximum temperatures are very far apart) – also known as continental.

For example, in winter the temperature in Johannesburg is a maximum of 25°C and a minimum of 1°C (extreme), whereas in Durban the maximums 24°C and the minimum is 15°C (moderate).
The warm Agulhas current flows along the south coast. However, you do not need to know how it affects the country’s climate.
The ocean currents also affect the temperatures and rainfall:

• The currents on our east and west coasts have the greatest impact on South Africa’s climate.
• The warm Mozambique current flows along our east coast.
• The cold Benguela current flows along our west coast.
• The warm Mozambique current causes high temperatures and more rain on the east coast.
• The cold Benguela current causes low temperatures and less rain on our west coast.

Because of the influence of these currents, temperatures are higher on the east coast than on the west coast. Figure 1.3.1A shows the ocean currents that affect South Africa’s climate and the resultant minimum temperatures.

Figure 1.3.1B shows the ocean currents that affect South Africa’s climate and the resultant maximum temperatures.
Figure 1.3.1C shows the seasons in which rainfall is received in South Africa. The black arrow shows how rainfall decreases from east to west across the country mainly due to the Mozambique and Benguela currents.

• The east coast gets rain all year round, so it will have a higher rainfall.
• The west coast is an arid (desert) region so it receives very little rain.

To prepare well for the exam and to understand this topic better, find out the cause of the winter rainfall in the south-western Cape.
1.3.2 The impact of the plateau on South Africa’s climate South Africa is situated mostly on a plateau (a flat area found at a high altitude).
Figure 1.3.2A below is a cross-section of South Africa from west to east showing the relief (landscape) of the country.
The higher you go, the cooler it gets. Therefore, places on the plateau (high altitude) will experience lower temperatures than places at a lower altitude.
Places in the Lowveld (Mpumalanga) have higher temperatures than places on the Highveld (Gauteng and Free State).

1.3.3 The impact of the subtropical high pressure belt on South Africa’s climate
South Africa is affected by three high pressure cells:

• South Atlantic high pressure (SAHP)
• South Indian high pressure (SIHP)
• Kalahari high pressure (KHP)

To prepare well for the exam and understand this topic better, find out how the Kalahari high pressure causes the plateau to receive summer rainfall only.
Figure 1.3.3A below shows the position of the three high pressure cells in and around South Africa.

• The South Atlantic high pressure causes cool, dry winds to blow onto the south-western Cape.
• The South Indian high pressure causes warm, moist winds to blow onto the east coast.
• The Kalahari high pressure has the greatest impact on South Africa’s climate:
  • It causes generally clear skies and warm temperatures because the air is descending and dry (in winter).
  • It results in only summer rainfall occurring on the plateau.

Activity 1
Study the synoptic weather chart in Figure 1.3.3B below and answer the questions that follow.

1. Name the high pressure cells labelled A and B. (2 × 2 = 4)
2. Give TWO pieces of evidence from the map that this is a summer map. (2 × 2 = 4)
3. Identify the low pressure cell labelled E. (1 × 2 = 2)
4. The letter G indicates a mid-latitude cyclone.
   1. Name the fronts labelled F and H. (2 × 2 = 4)
   2. In which direction does this cyclone generally move? (1 × 2 = 2)
   3. Describe how front F will affect the weather of Cape Town. (3 × 2 = 6)
5. Refer to the cyclone named Cathy.
   1. What type of cyclone is Cathy? (1 × 2 = 2)
   2. State how many cyclones have occurred for this season, including Cathy. (1 × 2 = 2)
   3. In which direction does this cyclone move? (1 × 2 = 2)
   4. List TWO conditions necessary for this cyclone to form. (2 × 2 = 4)
6. Refer to the weather station labelled D and describe the weather in terms of: cloud cover, wind speed, wind direction, air temperature, dewpoint temperature. (4 × 2 = 8)
   [40]

1.4 Local climate (valley and city climate)

Valley climate occurs on a local scale and lasts for a few hours. In this section we will focus on:

• Anabatic and katabatic winds
• Aspect

Anabatic means ‘moving upward’ and katabatic means ‘going downhill’.
1.4.1 Anabatic and katabatic winds
The structure of a valley and the heating and cooling that occurs during a day cause anabatic and katabatic winds to occur. This is shown in Figures 1.4.1A and 1.4.1B.
In the exam, you may be asked to draw, label or describe how anabatic or katabatic winds form in valleys. Learn to redraw and label Figures 1.4.1A and 1.4.1B below.
Effect of anabatic winds on settlements

• Anabatic winds take pollution out of the valley.

Effects of katabatic winds on settlements

• Katabatic winds trap pollution in the valley.
• Katabatic winds bring cold temperatures to the valley.

Katabatic winds lead to the development of the thermal belt (zone of warmer temperature above the valley floor) and a frost pocket (an area of very cold temperatures at the bottom of a valley where frost occurs) in a valley at night. This is shown in Figure 1.4.1C.

Effects of warm thermal belt on settlement and farming

• People will build their houses halfway up the slope of a valley to be in the warmer thermal belt (point A on Figure 1.4.1C).
• Crops which need warm, frost-free conditions will be planted in the thermal belt, for example sugar cane (point A on Figure 1.4.1C).

Effects of frost pockets on settlement and farming

• Crops which can withstand cold conditions (such as frost) can be planted at the bottom of the valley, for example potatoes (point B on Figure 1.4.1C).
• Pollution is trapped in the cold air below the temperature inversion at night, as shown in Figure 1.4.1D.

1.4.2 Aspect
Aspect refers to the direction in which a slope faces. This determines whether the Sun’s rays will hit the side of the valley directly or indirectly (obliquely). We will focus on how aspect influences the temperatures of north- and south-facing slopes in the southern hemisphere.
In the exam, you may be asked to draw, label or describe how the thermal belt and a frost pocket form in valleys. Learn to redraw and label Figure 1.4.1C.
Let us look at how the Sun’s rays affect slope temperatures in the southern hemisphere:

• North-facing slopes receive the direct rays of the Sun, making them warmer.
• South-facing slopes receive the indirect rays of the Sun, making them cooler.

Figure 1.4.2A shows how aspect influences the temperatures of north- and south-facing slopes in the southern hemisphere.
Activity 2
Figure 1.4.2B (left) illustrates valley climates. Study the diagram and answer the questions that follow.

1. Name the valley winds depicted in A and B. (2 × 2 = 4)
2. State ONE advantage of the wind labelled A. (1 × 2 = 2)
3. Name the layer labelled C. (1 × 2 = 2)
4. Explain how the wind labelled B influences:
   1. Farming in the valley (2 × 2 = 4)
   2. Industry in the valley (2 × 2 = 4)
      [16]

In the exam, you may be asked to draw, label or describe how aspect affects the temperature on a north- or south-facing slope in the southern hemisphere.
Answers to activity 2 continued
1.4.3 City climates
Urban areas (cities) experience a different climate compared to the surrounding rural areas. This results in the formation of a heat island over the city. In this section, we will focus on the causes of a heat island. An urban heat island is when the city has warmer temperatures than the surrounding rural areas.
In the exam, you may be asked how the temperatures change as you move towards the centre of the city. Figure 1.4.3A shows how the temperatures increase the closer you get to the city centre (also called the Central Business District, or CBD). Note also the lower temperatures over the park.
In the exam, you may be asked to say what causes a city to be warmer.
Table 1.2 below lists the factors that cause higher temperatures in the city.

Table 1.2: Factors that cause a heat island
Sustainable ways to reduce the urban heat island effects

• Promote greenbelts (plan and have more parks or recreational areas with trees and plants).
• Plant more trees in the city.
• Increase vegetation cycles by planting rooftop gardens.
• The new buildings should not be built with material like glass or any reflecting material.
• The height of the buildings should have a limit.
• Have laws that force the factories to reduce the amount of pollution they produce.
• Improve and encourage people to use public transport.
• Promote lift clubs to work or to school.

On this page you will find ECONOMIC GEOGRAPHY OF SOUTH AFRICA GRADE 12 NOTES – GEOGRAPHY STUDY GUIDES This chapter covers South Africa’s economic activities,This chapter covers South Africa’s economic activities,as well as food security.
Key concepts

If you know and understand all the definitions of economic geography, you will be able to answer most of the questions in the economic geography section of the final exam. Use mobile notes to help you memorise these key concepts. Instructions for making them are on page x in this guide.
In an exam you may be asked to test your understanding of terms by matching the key concept with the definitions provided. An example of this kind of question is provided in activity 4.1 on page 80. Practise this by completing the activity.

Take care not to confuse the terms gross domestic product (GDP) and gross national product (GNP) with one another. GDP refers to the total value of goods and services produced in one year within the borders of South Africa. GNP refers to the total value of goods and services produced in one year by the permanent citizens of a country (even if they live and work in another country).

Activity 4.1
Choose a term from Column B that matches a statement in Column A. Write only the letter (A to F) next to the question number (1 to 5), for example 6 – G.

In the next section we focus on primary, secondary and tertiary economic activities. These economic activities are important to the economy and the country’s development, and are interdependent. Primary activities stimulate secondary activities which, in turn, stimulate job creation in the tertiary sector.

4.1 Primary economic activities

Primary activities involve extracting (removing) raw materials from the earth, for example farming, fishing, forestry and mining. We focus on farming and mining as they are the two primary activities that contribute the most to South Africa’s economy.
4.1.1 Farming in South Africa
In this section we focus on factors that favour and hinder farming. There are different types of farming: crop farming, stock farming and mixed farming (both crop and stock). The word ‘agriculture’ is used to refer to all types of farming. Firstly, pay attention to Table 4.1, where the differences between a large scale farmer and small scale farmer are explained.
Table 4.1 The differences between a large scale farmer and a small scale farmer

Factors favouring (promoting) farming
These factors make farming more productive and profitable:

• There is a high demand (market) for farming products so farmers sell their crops more easily. Farmers’ profits rise when they can sell for a higher price to overseas markets with a demand for their crops or stock.
• The fertile floodplains of rivers allow farmers to produce more crops or grazing land (pastures) in these areas. This supports farming and increases profits.
• The eastern half of the country gets more than 500 mm of rain a year. This makes it possible to produce more crops and ensures greener pastures for stock farming, therefore increasing profits.
• The relatively high summer temperatures help crops to grow and increase crop production. It also ensures greener pastures for stock farming.
• Availability of labour (workers)

Use the following word mnemonic to help you remember the factors that favour farming in South Africa:
F = Fertility → Farmer
D = Demand → Daniel
R = Rain → Reaps
T = Temperatures → Tomatoes

Factors hindering (restrict/limit) farming
These factors make farming difficult and therefore less productive and less profitable:

• Rainfall is low and unreliable on the plateau, which limits crop production and decreases available pastures for stock farming.
• Soil erosion due to incorrect farming methods increases farming costs and decreases profits.
• Natural hazards such as droughts, floods and hail storms damage crops and stock and decrease production and profits.
• HIV and AIDS have a negative impact on the health and productivity of farm workers.
• Price fluctuations (when prices go up and down) make it difficult for farmers to stay in business and make a profit.
• Pests which affect crops and stock are costly to control and cause a decrease in production and profits.

Use the following word mnemonic to help you remember the factors that hinder farming in South Africa:
H = Hazards → Hungry
P = Price → People
S = Soil →Seek
H = Health → Healthy
R = Rainfall v Round
P = Pests v Potatoes

Importance of farming in South Africa (role of farming in SA)
Farming benefits the economy and people in these ways:

Farming provides jobs to people and so decreases unemployment.

• Farming provides food to the country so less food needs to be imported. Food that is supplied locally is less expensive than imported food.
• Farming equipment is expensive because much of it is imported, but South Africa has reduced these costs by manufacturing some equipment locally, for example irrigation systems.
• Farming involves moving crops to the markets, which in turn leads to improving the country’s infrastructure (roads, railways and communication systems).
• South African farming products are exported to other countries earning us foreign exchange. This improves the country’s economy.

In an exam you may be asked to state the factors that favour or hinder farming. You may also be asked to explain the importance of farming to South Africa.

Food security and insecurity
Food security is when all the people have enough food to meet their needs for a healthy and productive life. Some of the factors (reasons) why people have enough food (food security) are:

• Commercial farms are able to produce enough food due to favourable climatic factors.
• People can afford to buy the food. In other words, farmers have a market.
• The need to import food from other countries at high costs is reduced because food is grown locally.
• Genetically modified crops are more resistant to diseases, pests and viruses so more crops can be produced.

Food insecurity is when not all the people have enough food to meet their needs for a healthy and productive life. Food insecurity affects poor people, many of whom live in rural areas. These people try to survive by growing their own food. This is called subsistence farming. This type of farming provides only enough food for the farmer’s own family.
Some of the factors (reasons) why people do not have enough food (food insecurity) are:

• There is a lack of fertile (arable) land on which to grow food.
• Climate change increases natural disasters (droughts and floods) that damage crops.
• When you are poor it is more difficult to buy the things you need to farm, such as enough land, equipment, seeds and irrigation systems.
• Subsistence farmers are often uneducated about ways to improve crop production so land is often overused for crops or overgrazed by cattle.

Some of the measures (ways) to prevent food insecurity are:

• Prevent soil erosion by practising better farming methods, for example crop rotation or rotational grazing (putting cattle in different fields or camps).
• Use efficient ways of storing food, especially when more crops are produced in high-rainfall seasons.
• Improve ways of storing and using water supplies to reduce water wastage.

In an exam you may be asked to define the terms food security and food insecurity and state the factors that lead to food security and food insecurity. Learn this information to answer this question.
Apply what you have learnt about food security by completing activity 4.2 on page 83.

Activity 4.2
The cartoon in Figure 4.1.1 below shows how environmental problems can affect food security.

1. How has the use of fossil fuels and fertilisers caused climate change? (3 × 2 = 6)
2. How does climate change link to rising sea levels? (2 × 2 = 4)
3. How would rising sea levels affect food security? (1 × 2 = 2)
4. Explain your answer in question 3. (1 × 2 = 2)
5. Name another factor in the cartoon that would affect food security. (1 × 2 = 2)
   [16]

4.1.2 Mining in South Africa
In this section we focus on factors favouring and hindering mining. There are different types of mining: open cast and shaft mining.
Factors favouring (promoting) mining
These factors make mining more productive and profitable:

• South Africa has many different minerals which can be mined and used in factories or exported so the country earns foreign exchange.
• South African mines benefit from having lots of local unskilled labour. This results in lower labour costs and therefore higher profits.
• Foreign skilled miners come to work in South African mines and the mines benefit from their knowledge and skills.
• Many countries invested money in our mines, which assisted with further development of the mines and a lowering of costs.
• A well-developed infrastructure (roads and railway lines, water and electricity) assists mines to do business.

Use the following word mnemonic to help you remember the factors that favour mining in South Africa:
M = Minerals →Miners
L = Labour → Love
F = Foreign → Finding
I = Investment → Important
I = Infrastructure → Irons

Factors hindering (restrict/limit) mining
These factors make mining less productive and less profitable:

• The high temperatures in some underground mines create difficult working conditions and this decreases productivity.
• Large distances between the mines and the harbours or towns increase the cost of transporting the minerals to the markets.
• There are high costs involved in training and housing mine workers.
• Mine worker strikes decrease productivity and profits.
• Water shortages and underground flooding of mines are a serious problem. It is expensive to fix the problem and this decreases profits.
• Ensuring safety on the mines is costly, especially when tunnel roofs collapse.

Use the following word mnemonic to help you remember the factors that hinder mining in South Africa:
S = Safety → Sometimes
W = Water → Workers
C = Costs → Can
D = Distances → Dig
T = Temperatures → Too
S = Strikes → Slowly

The importance of mining to the South African economy (role of mining in SA)
Mining benefits the economy and people in these ways:

• The mining sector provides many jobs, which decreases unemployment.
• Mines supply raw materials to secondary activities such as factories and industries. This in turn stimulates industrial development.
• When mines start up, new towns and transport networks develop around the mines.
• Mining stimulates other sectors of the economy, such as farming, building and trade, to meet the needs of the growing number of people who live and work in mining towns.
• Harbours, like those at Saldanha Bay (Western Cape) and Richards Bay (KwaZulu-Natal), expand (grow bigger) to cope with increased mineral exports to other countries. This creates more jobs and also helps other sectors of the economy to grow.
• The export of mining products increases the profits of the mines because they earn foreign exchange.

Impact of mining on the environment
The processes involved in removing minerals from the earth create waste products and have a negative effect on the environment. Some of the negative effects of mining are:

• The natural vegetation is removed to clear the ground for mining activities. This leads to an increase in soil erosion in these areas.
• When vegetation is removed it destroys natural habitats and damages ecosystems, which can lead to the extinction of plants and animals in the area.
• The land is destroyed when mine dumps and slimes dams are built to store waste.
• Chemicals that leach (wash off) from the mine dumps when it rains cause water and land pollution.
• Sinkholes are a danger in areas where mining takes place.
• Coal is a major mining product in South Africa. Power stations burn coal to make electricity. The carbon dioxide that is released during this process contributes to global warming and climate change.

In an exam you may be asked to state the factors that favour or hinder mining. You may also be asked to explain the importance of mining to South Africa and the impact of mining on the environment.

4.2 Secondary economic activities

Secondary activities involve the processing of raw materials and manufacturing of goods. We use the word ‘industries’ for secondary activities. For example, sugar cane is turned into sugar at an industry called a sugar refinery; trees are turned into wood shavings and then paper at an industry called a sawmill; cowhides are turned into leather to make handbags and shoes at an industry called a tannery.
Secondary activities can be divided into heavy and light industries. Learn the information in Table 4.2 below to understand the differences between these two types of industries.

In an exam you may be asked to identify a heavy or light industry from a picture or on a topographic map. You may also be asked to state the characteristics of heavy or light industries. Learn the information in Table 4.2 to help you answer these questions.

Table 4.2: The differences between heavy and light industries

In the next sections we focus on factors that affect the location of industries and the factors that favour or hinder the development of secondary economic activity. We look at the development of the four main industrial regions in South Africa:

• Pretoria–Witwatersrand–Vereeniging complex (PWV) (Gauteng)
• Durban–Pinetown (Ethekwini)
• Port Elizabeth–Uitenhage (Nelson Mandela Bay)
• Southwestern Cape

4.2.1 Industrial development in South Africa
The availability of raw materials in South Africa has led to the development of large industries (factories) that process the raw materials or use semifinished products to manufacture final products.

Factors affecting the location of an industry
When deciding where to site an industry, the following two factors are the most important:

• Raw materials: How close are the natural resources or raw materials the industry needs to make its product?
• Markets: How close is the industry to the market where it sells its product? In other words, how close are the consumers (the people that buy the product)?

An industry will locate itself close to either the raw materials or the market. If the raw material is large and difficult to transport, the industry will locate close to the raw material. This industry would be called raw-material orientated.
If the raw material is smaller and easier to transport, the industry will locate close to the market. The industry would be called market orientated.
The following factors can also affect the location of an industry:

• Transport: Access to major transport routes between the industry, the raw material source and the market.
• Energy: A reliable supply of electricity is needed to be able to process raw materials or manufacture goods.
• Labour: A skilled and unskilled work force must live in the area where the industry is located.
• Link industries: These are industries that you sell your product to. How close the industry is to its link industries will affect its transport costs.
• Government policies: Government may offer subsidies or tax incentives to industries that locate in certain areas, which may help to decrease costs.

Factors favouring (promoting) industrial development in South Africa
These factors make industries more productive and more profitable:

• South Africa has a wide range of industries because there is a wide range of raw materials to support production.
• A well-developed infrastructure (roads and railway lines, water and electricity) assists industries to do business.
• The availability of cheap, level (flat) land makes it cheaper to develop industries in South Africa.
• The availability of a large skilled and unskilled labour force in the areas where industries are located decreases the costs of training and worker accommodation and transport.

Factors hindering (restricting/limiting) industrial development in South Africa
These factors make industries less productive and less profitable:

• The large distances between South Africa and its foreign markets increase transport costs and make it more difficult to compete with industries in those countries.
• There is a shortage of skilled labour in South Africa. This increases labour costs because industries have to attract foreign skilled labour and pay high salaries to retain skilled workers.
• Labour strikes decrease the productivity of industries in South Africa and this increases costs and limits further industrial development.
• Water and electricity shortages and price increases limit further industrial development.

Importance of industrial development in South Africa

• When we export processed goods we earn more foreign exchange than if we exported the raw material.
• Industries provide more and higher paid employment to the population, this in turn leads to an increase in the standard of living of the population. This increases their buying power which further stimulates industrial development. It also increases the money made from rates and taxes, so the government has more money to spend on improving infrastructure and other facilities.
• The employment of people in industries leads to the development of more skills and experience; this in turn leads to the development of new technology.
• Industrial growth stimulates the development of all other services and facilities.

Main industrial regions in South Africa
Figure 4.2.1A on page 88 shows the four main industrial regions in SouthFigure 4.2.1A on page 88 shows the four main industrial regions in SouthAfrica.
Activity 4.3
Choose a term from the box that matches the descriptions that follow. heavy industries; footloose industries; market-orientated industries; centralisation; decentralisation; Durban–Pinetown; Gauteng/Pretoria–Witwatersrand–Vereeniging

1. Over-concentration of industries in a few core areas
2. The largest industrial core area in South Africa
3. Industries that can locate anywhere due to improved technology
4. Industries that must be close to the consumers
5. These industries are associated with high noise and air pollution
   (5 × 2 = 10)

Strategies for industrial development
As part of the development plan for underdeveloped regions, the South African Government (Department of Trade and industry in partnership with the Department of Transport) introduced TWO development plans:

• Spatial Development Initiative (SDI)
• Industrial Development Zones (IDZ)

4.3 Tertiary economic activities

Tertiary economic activities involve the selling of goods and provision of services. For example, the selling of goods would include any supermarket, car dealer or clothes shop. Examples of services are hairdressers, doctors, internet cafes, and repair and maintenance companies.
Tertiary economic activities are divided into the formal sector and informal sector. In this section we will focus on the informal sector in South Africa, its characteristics and the reasons for its development. We will also look at the challenges facing this sector and how the informal sector can be improved.
4.3.1 The informal sector in South Africa
Examples of people who work in the informal sector are hawkers, parking guards and casual labourers (painters, tilers, gardeners, cleaning staff).

• If not registered, then they don’t pay income tax.

Characteristics are the things that members of a group have in common.

Characteristics of the informal sector
The informal sector has the following characteristics:

• Workers are self-employed.
• Women and children are mainly involved in this sector.
• It is associated with casual labour.
• It employs unskilled or semi-skilled workers.

Importance of the informal sector
The informal sector benefits the economy and people in the following ways:

• It provides an income to many people and decreases unemployment.
• Informal traders are more accessible to working class consumers.
• Consumers can buy goods in smaller quantities and at a lower price.
• It provides opportunities for people to grow and apply their entrepreneurial skills.

Reasons for the development of the informal sector

• Large scale job losses in the formal sector increase the number of people who make work for themselves in the informal sector.
• Greater mechanisation (use of machinery) on farms and in industry results in more workers being unemployed and needing to make work for themselves in the informal sector.
• People who lack formal qualifications are less likely to be employed in the formal sector, causing them to make work for themselves in the informal sector.
• Immigrants who are not able to find legal employment in the formal sector turn to the informal sector to make an income.

Do not confuse the terms informal sector and informal settlement with one another:

• Informal sector is the economic term for people not employed in the formal sector.
• Informal settlement refers to ‘squatter’ areas, where people live.

Problems or challenges facing the informal sector
These factors make informal trading less productive and less profitable:

• Traders are frequently harassed by local authorities.
• Traders do not have access to proper trading facilities.
• Traders and their goods are exposed to the weather.
• Banks do not like to give loans to informal traders.
• The sector is unpredictable and the income unreliable.

Measures to improve the informal sector
These are some of the things that can be done to help informal traders:

• Local authorities can provide specific areas for informal trading.
• Local authorities can provide infrastructure, such as hawker stalls.
• Banks can make access to bank loans easier.
• Local authorities can provide training to teach people the necessary skills to develop their businesses.

4.4 Quaternary economic activities

Quaternary economic activities deal with communication, technology and research. Examples of quaternary activities are new product development, medical research, customer surveys and market research, call centres, facebook, Google and other information age businesses.

Activity 4.4
Choose a description from Column B that matches a term in Column A.
Write only the letter (A-L) next to the question number (1-10), e.g. 11.L

The economic geography section will appear in Section B of the theory paper in Questions 3 and 4. Note that you will be asked to answer questions based on information contained in texts, graphs and tables. The answers can be found in the information given, so read the information carefully to find the answer.

The next section will help you to understand graphs and tables in economic geography. Learn this information to prepare for this section of the exam.

4.5 Understanding graphs and tables

In the exam, economic concepts are often tested using tables or graphs. It is important that you understand how to get information from a graph or table to answer such questions.
When a question in the exam refers to a table or graph, it is important that you study the table or graph before you read the questions. This is similar to reading a comprehension text before answering the questions. You will need to UNDERSTAND the table or graph in order to answer the questions.
4.5.1 Understanding graphs
In this section we look at two types of graphs: bar graphs and pie charts.
Follow these steps when you read a graph:

Let us apply these steps by looking at specific examples in Figure 4.5.1A (right) and 4.5.1.B on page 95.
Here are some helpful guidelines that show you to how to read and understand graphs.

Example of a bar graph
Carefully study the bar graph in Figure 4.5.1A below which shows the contribution of different economic sectors to South Africa’s GDP (Gross Domestic Product).

Activity 4.5
The following questions refer to the graph in Figure 4.5.1A on page 94.

1. What do the letters GDP stand for? (1 × 2 = 2)
2. Which industry contributes the most to the GDP? (1 × 2 = 2)
3. To what economic activity does mining and agriculture belong to? (1 × 2 = 2)
4. Mining and agriculture contribute less to the GDP than manufacturing, which is a secondary activity. Explain the reason for this observation. (2 × 2 = 4)
5. The contribution of transport to the GDP increased from 1995 to 2002. Give a possible reason for this. (1 × 2 = 2)
   [12]

Example of a pie chart
Carefully study the pie chart or pie graph below (Figure 4.5.1B) illustratingCarefully study the pie chart or pie graph below (Figure 4.5.1B) illustratingthe contribution of different provinces to the national GDP.

Activity 4.6
The following questions refer to Figure 4.5.1B on page 95.

1. Rank the top three provinces in terms of their contribution to the GDP from largest to smallest contribution. (1 × 2 = 2)
2. Give two reasons why the province ranked first in your answer in question 1 holds that position. (2 × 2 = 4)
3. The following questions refer to the province which contributes the least to the national GDP.
   1. Name the province which contributes the least to the national GDP. (1 × 2 = 2)
   2. Name the ocean current that flows alongside this province. (1 × 2 = 2)
   3. What impact does this ocean current have on the rainfall in this province? (1 × 2 = 2)
   4. Explain how your answer in question c) affects the province’s contribution to the GDP. (2 × 2 = 4)
      [16]

4.5.2 Understanding tables
In this section we look at how to read and understand the information in a table. Follow these steps when you read a table:

Carefully study Table 4.4 below and then follow the steps to read the table.

Table 4.4

On this Page you will find MAPWORK GRADE 12 NOTES – GEOGRAPHY STUDY GUIDES

5.1 Introduction

Mapwork is a practical section of Geography where you are required to apply all the different skills, techniques and the theory that you have learnt. It consists of the following sections:

• Mapwork calculations
• Reading, interpretation and analysis of theory
• Geographical Information Systems (GIS)

Maps tell you a story about a place. Look at all the information given on the map to interpret it:

• What is the name on the top of the map?
• Look at the latitude and longitude. Get an idea where the map is. For example, 20°S would indicate it is in Limpopo.
• Look at all the information provided (magnetic declination information, scale of the map, contour interval, map projection used) in the ‘margins’ of the map.
• Look at the bottom of the map, for the diagram showing the map sheet reference. It may show additional information such as oceans or borders.
• Notice where roads or railways go off the map. The town they lead to may give you clues.
• Make use of the key/reference list to identify features. Remember, the first word in the reference list refers to the first picture and not both pictures.

Look for the following aspects on the map:

• Is this a high or low rainfall area? Is the rainfall seasonal?
• What kinds of rivers are visible and how many are there?
• Identify the urban and rural areas.
• Identify the different land uses in the mapped area, for example, agricultural/industrial/built-up areas.
• What factors may have affected the location of various land uses?
  For example, industry alongside a perennial river.
• Identify the type of farming – is it commercial or subsistence?
• Look at the relief – is it flat or hilly, are the slopes steep or gentle?
• Look at the contour lines to determine this.

Look at the information given in the orthophoto:

• Is the orthophoto labelled? If not, check the numbers or letters in the question, for example: ‘Identify land use labelled G on orthophoto’ – G will only be on one of the photos.
• Is a rectangle drawn around the area covered by the orthophoto? If not, orientate the photo to the map.
• Read the instructions carefully as you may need to use both the map and the photograph to answer a question.
• Make use of all the information on the orthophoto, for example, road names, heights, etc.

Remember your calculator, protractor, 30 cm ruler and a pencil.

A topographic map is a way to show mountains, valleys and aspects of a landscape by means of contour lines and intervals.
An orthophoto map is a corrected aerial photograph. Human-made and other features that are not clear are labelled on the orthophoto.

5.2 Some basic mapwork concepts

1. Direction is expressed using the points on a compass – North, South, East and West, and the points between them. These are known as the 16 cardinal points.
   
2. The three main lines of latitude that run across the surface of the Earth are the equator, the Tropic of Cancer and the Tropic of Capricorn. The equator is the longest line of latitude (where the Earth is widest in an East–West direction). It is located at 0 degrees latitude. The equator divides the planet into the northern and southern hemispheres. The Tropic of Cancer is located at 23¹/₃° north of the equator. The Tropic of Capricorn lies at 23¹/₃°  south of the equator. The Tropic of Capricorn runs through northern South Africa.
   
3. Reading a map is as easy as reading a book but, instead of using the alphabet, you have to know the conventional signs used in maps. These help you to see the landscape (relief, drainage, vegetation and huhuman-made features). Conventional signs are used to show particular features. They may be letters of the alphabet or symbols. Many symbols look like the features they represent.

Use the following mnemonic to remember the order of the compass points:
N – Never North
E – Eat East
S – Silk South
W – Worms West

The following table lists some of the symbols you may find on a map:

Table 5.1: Symbols found on maps

Colours are often used to make symbols clearer. There are six colour groups:

Table 5.2: Colours used on maps
4. Contour lines on a map show the area’s relief (the difference in elevation) or altitude (height in metres of the land above sea level).
The closer together the contour lines are, the steeper the slope is.

The lines are labelled so that you read up the slope.

5.3 Mapwork calculations

5.3.1 Introduction to mapwork calculations
In this section you will learn how to do various mapwork calculations on a topographic map and an orthophoto. These calculations will be explained by means of examples.
When doing calculations, you will be required to give an answer in kilometres or metres. Always take note of whether the calculation is to be done from a topographic map or an orthophoto, as this will change your scale. The orthophoto scale is larger and provides more detail. Use the conversion table below (Table 5.3).

Table 5.3: Converting a given scale to kilometres or metres

Calculations in mapwork need a good understanding of difference in height and straight line distance to calculate distance, gradient and area.
Look at the example and revise these calculations.
Learn the conversions given in Table 5.3 below.

Example
On a 1:50 000 map

Difference in height (vertical)
Simply subtract the smaller height from the greater height.
For example, to calculate the difference in height between spot height
1 260 and spot height 1 200:
1 260 − 1 200 = 60 m

Straight line distance (horizontal)
Measure the distance on the map in centimetres and multiply by the scale.
For example, to calculate the distance between spot height 1 200 and spot height 1 260 in kilometres:
Map distance = 2,4 cm
Scale: 1 cm represents 0,5 km
2,4 × 0,5 = 1,2 km

5.3.2 Mapwork calculations: distance, area and gradient
In the exam you may be asked to do distance, area and gradient calculations on a topographic map or an orthophoto. The following are examples of these calculations for both topographic maps and orthophotos. The method and formulae are the same for both kinds of maps, but remember to use the correct conversion calculation on page 103.

Distance
This is the straight line distance from one point to another or the actual distance, e.g distance along a road, railway, hiking trail, etc.
We calculate distance to find out how far one place is from another.

Method for calculating distance
Follow these steps:
Step 1: Measure the map distance in centimetres.
Step 2: To convert to kilometres, multiply the map distance by 0,5 if on a topographic map, or by 0,1 if on an orthophoto to get km. To convert to metres, multiply the map distance by 500 if on a topographic map or by 100 if on an orthophoto.

Always take note of the unit in which the answer must be given, for example km or m.
If the exam question asks for “the distance along a road” then you would measure the line as if you were walking on it.

Worked example 1 – straight line distance
Calculate the distance from point A to point B.

Worked example 2 – actual distance
Calculate the distance along the road from point A to point B.

Activity 5.1
Calculate the following distances which are shown on a topographic map.

1. Calculate the distance from trig. station 5 to spot height 120 in metres. (3)
2. Calculate the distance along the powerline in kilometres. (3)
   [6]

Activity 5.2
Calculate the following distances which are shown on an orthophoto.

1. Calculate the distance from the post office to the dipping tank in metres. (3)
2. Calculate the distance along the track in kilometres. (3)
   [6]

Area
Area is the amount of surface a two-dimensional shape covers. (A twodimensional shape has length and breadth.)
We calculate area to find out how much land is covered (e.g. by a maize field) or how much space we have to build on.

Method for calculating area
Follow these steps:
Step 1: Measure the length in cm and convert to km or m.
Step 2: Measure the breadth in cm and convert to km or m.
Step 3: Apply the formula A = L × B.
Step 4: Write the answer in kilometres squared (km²) or metres squared (m²).

Worked example

Topographic map calculation:	Orthophoto calculation:
Answer in km² A = L × B L: 4,4 cm × 0,5 = 2,2 km B: 3,6 cm × 0,5 = 1,8 km A: 2,2 × 1,8 = 3,96 km² Answer in m² A = L × B L: 4,4 cm × 500 = 2 200 m B: 3,6 cm × 500 = 1 800 m A: 2 200 × 1 800 = 39 600 m²	Answer in km2 A = L × B L: 4,4 cm × 0,1 = 0,44 km B: 3,6 cm × 0,1 = 0,36 km A: 0,44 × 0,36 = 0,1584 km² Answer in m2 A = L × B L: 4,4 cm × 100 = 440 m B: 3,6 cm × 100 = 360 m A: 440 × 360 = 158 400 m²

Activity 5.3

1. The block below is shown on a topographic map. Calculate the area of the block in metres squared.
   (5)
2. The block below is shown on a topographic map. Calculate the area of the block in kilometres squared.
   (5)
   [10]

Always write the formula A = L × B. It’s an easy mark.

Activity 5.4

1. The block below is shown on an orthophoto. Calculate the area of the block in metres squared.
   (5)
2. The block below is shown on an orthophoto. Calculate the area of the block in kilometres squared.
   (5)
   [10]

Gradient
Gradient is the relationship between height and distance. The gradient tells us how steep a straight line is.
We calculate gradient to find out how steep or gentle a slope is.
Formula for gradient

Method for calculating gradient
Follow these steps:
Step 1: Calculate the difference in height by subtracting the lowest height from the highest height. The answer must be in metres.
Step 2: Measure the distance in cm.
Step 3: Convert to metres by multiplying by 500 (if you are working with a topographic map) or by 100 (if you are working with an orthophoto).
Step 4: Write the two answers as a ratio.
Step 5: Divide both sides of the ratio by the height. This is so we can get a ratio of 1 to a relative number, in other words, distance.
Step 6: Your answer is the gradient written as a ratio.

Worked example

Topographic map calculation:	Orthophoto calculation:
Calculate the gradient between 5400 and ·5000 G = H D H: 5 400 – 5000 = 400 m D: 2,2 cm × 500 = 1 100 m G: 400:1 100 400:400 = 1:2,75	Calculate the gradient between ·5400 and ·5000 G = H D 5 400 – 5 000 =  400 11 cm × 100     1 100 400: 1 100 400 = 1:2,75

Always write the formula G = H  in your answer. This will give you a mark.
D
Activity 5.5
Calculate the gradient from trig. station 8 to spot height 1120, which are shown on a topographic map.

Note that 8 is the number of the trig. station. The height is written below the triangle, i.e. it is 980.

Activity 5.6
Calculate the gradient from trig. station 8 to spot height 213, which are shown on an orthophoto. [5]

5.3.3 Mapwork calculations: True bearing, magnetic declination, magnetic bearing, position, map sheet reference, vertical exaggeration
Note that true bearing, magnetic declination, magnetic bearing and position, and map sheet reference calculations can only be done on a topographic map. Vertical exaggeration calculations can be done on both a topographic map and an orthophoto.

True bearing
True bearing is the angle measured clockwise from true north (0°).
We calculate true bearing, magnetic declination and magnetic bearing to help us determine in which direction we are going or to help us find our way.

The true bearing from A to B is 138°. (In the exam, a degree either way will be accepted, i.e. the answer can be 137° to 139°.)

Always remember to move to the right (clockwise).

Activity 5.7

1. Calculate the true bearing from trig. station 8 to spot height 110. (2)
2. Calculate the true bearing of trig. station 8 from spot height 110. (2)
   [4]

Magnetic declination
Magnetic declination is the angle between true north and magnetic north. This angle is calculated when the map is drawn, but the position of magnetic north changes, so the angle between true north and magnetic north (the magnetic declination) will also change. You will need to calculate what the magnetic declination is for the current year.
You will find the magnetic declination for the year the map was drawn on the map. This information appears on a map on the left-hand side or at the bottom of the map. You need this information to do the magnetic declination calculation. Look at the following example:

Example
Mean magnetic declination (MD) 20º 10’ west of true north (1990.01)
Mean annual change (AC) 2’ westwards (1985–1995)

Note the following:

TN is true north. This is found at the North Pole.

• MN is magnetic north. This is the direction in which a compass would point.
• MD is the magnetic declination. It is the angle you are calculating.
• 1990.01 refers to the year and the month that the declination was recorded.
• 1985–1995 refers to the years the mapmaker used to get the mean (average) magnetic declination. You will not need these years.
• Mean annual change refers to how much the magnetic declination changes by each year. The change is in minutes (this is shown by the symbol ‘).
• The declination can change in a westerly (angle increases) or easterly (angle decreases) direction.

Worked example 1: If the annual change is westwards
Mean magnetic declination (MD) 20º 10’ west of true north (1990.01)
Mean annual change (AC) 2’ westwards (1985–1995)

Calculating magnetic declination for 2012
MD = 20° 10’ W of TN
AC = 2’ W
2012 – 1990 = 22 years
22 × 2’ W = 44’ W
MD = 20° 10’ W + 44’ W = 20° 54’ W of TN

Worked example 1: If the annual change is eastwards
Mean magnetic declination (MD) 18º 50’ west of true north (1985.01)
Mean annual change (AC) 1’ eastwards (1980–1990)

Calculating magnetic declination for 2012
MD = 18° 50’ W of TN
AC = 1’ E
2012 − 1985 = 27 years
27 × 1’ E = 27’ E
MD = 18° 50’ W – 27’ E = 18° 23’ W of TN

Worked example 3: If the magnetic declination is given with a decimal place instead of minutes
If the MD given on the map is recorded as a decimal, for example 23°,5 W, you must multiply the number after the comma by 6 to convert it to minutes. For example:
5 × 6 = 30’. So, the MD is now 23°30’ W. The decimal comma has been removed and you have a MD in degrees and minutes.
Now look at the following worked example:
Mean magnetic declination (MD) 18º,3 west of true north (1985.01)
Mean annual change (AC) 1’ westwards (1980–1990)

Calculating magnetic declination for 2012
MD = 18°,3 W of TN = 18° 18’ W of TN
AC = 1’ W
2012 – 1985 = 27 years
27 × 1’ W = 27’ W

Worked example 4: If the magnetic declination answer has the minutes greater than 59’
Once you have done your calculation, if the magnetic declination for the current year has minutes greater than 59’ you need to convert the minutes to degrees.
For example: MD = 23° 76’
76’ – 60’ leaves 16’. The 60 minutes you subtracted equal 1 degree, which you add to the 23° to get 24° 16’.
Now look at the following worked example:
Mean magnetic declination (MD) 31º 33’ west of true north (1990.08)
Mean annual change (AC) 2’ westwards (1987–1993)

Calculating magnetic declination for the current year
MD = 31° 33’ W of TN
AC = 2’ W
2012 – 1990 = 22 years
22 × 2’ W = 44’ W
MD = 31° 33’ W + 44’ W
= 31° 77’ W of TN
= 32° 17’ W of TN

Worked example 5: When the change is eastwards and the change is greater than the minutes in the MD
If the mean annual change has minutes greater than the minutes in the magnetic declination, you need to borrow a degree in the magnetic declination and convert it into minutes. Look at the following example:
MD = 20° 10’ W – 44’ E
Before you can subtract the mean annual change of 44’ E from the given magnetic declination, you need to borrow 1° from 20° and convert it to minutes. This leaves you with 19°. Now take the 1° and convert it to 60’ (remember that 1° = 60’). Now add the 60’ to the 10’. This gives you 70’. Now you can continue with the calculation:
19° 70’ – 44’ E = 19° 26’ W
Now look at the following worked example:
Mean magnetic declination (MD) 25º 32’ west of true north (1986.04)
Mean annual change (AC) 2’ eastwards (1983–1992)

Calculating magnetic declination for 2012
MD = 25° 32’ W of TN
AC = 2’ E
2012 – 1986 = 26 years
26 × 2’ E = 52’ E
MD = 25° 32’ W – 52’ E
= 24° 92’ – 52’
= 24° 40’ W of TN

Remember that 1° = 60’ (1 degree = 60 minutes)

• Always add degrees to degrees and minutes to minutes. Never add degrees to minutes.
• Always subtract degrees from degrees and minutes from minutes. Never subtract minutes from degrees!

Magnetic bearing
Magnetic bearing is the angle measured clockwise from magnetic north.
Here the magnetic north line is taken as 0º whereas in true bearing, true north is taken as 0°.

Method for calculating magnetic bearing
To get the true bearing and the magnetic declination we use the same methods applied in 5.3.3A (on page 111) and 5.3.3B (on page 112).
These methods are provided again below. Follow these steps:
Step 1: Measure the true bearing from A to B (as described in 5.1.3A)
Step 1a: Draw a straight line joining A and B.
Step 1b: Draw a north line through A (the point of measurement).
Step 1c: Place the 0 of your protractor at the top of the north line.
Step 1d: Moving in a clockwise direction from 0, read off where the line joining A and B touches the protractor.
Step 2: Calculate the magnetic declination (as described in 5.1.3B)
Step 2a: Work out the difference in years between the current year and year given on the map. Your answer must be in years. (Use the year that is printed straight after the words ‘true north’. You can ignore the month that is shown.)
Step 2b: Multiply the number of years with the mean annual change (this is given on the map) to get the change since the declination was recorded.
Step 2c: If the mean annual change is eastwards, then you have to subtract the change from the magnetic declination given. If the mean annual change is westwards, then you must add it to the given magnetic declination.
Step 2d: Your answer is the magnetic declination for the current year.
Magnetic declination is always west of true north.
Step 3: Now add the true bearing to the magnetic declination. Your answer must not have a direction (north, south, east or west) because it is an angle measured only in degrees and minutes.

Example
MD = 18°,8 W = 17° 48’ W
Change in years = 2012 – 1988 = 24 years
Change since 1989 = 24 × 4’ = 96’ W = 1° 36’ W
MD = 17° 48’ + 1° 36’
= 18° 84’ W = 19° 24’ W
TB = between 299° and 303°
MB = TB + MD
= 301° + 19° 24’
MB = 320° 24’

Always write the formula MB = TB + MD in your calculations as this will earn you a mark.

Worked example 1

Mean magnetic declination (MD) 20º, 2’ west of true north (2001.09)
Mean annual change (AC) 1’ westwards (1998–2004)

Calculate the magnetic bearing of the post office from the dipping tank for 2012.
MB = TB + MD
TB = 272° (271°– 273°)
MD = 20°, 2 W of TN = 20°12’ W of TN
AC = 1’ W
2012 – 2001 = 11 years
11 × 1’ W = 11’ W
MD = 20° 12’ W + 11’ W = 20° 23’ W of TN
MB = 20° 23’ + 272°
= 291° 23’– 293° 23’

Worked example 2

Mean magnetic declination (MD) 20º 31’ west of true north (1998.10)
Mean annual change (AC) 4’ westwards (1995–2001)

Calculate the magnetic bearing from trig. beacon 8 to spot height 120 for 2012.
MB = TB + MD
TB = 57° (56°– 58°)
MD = 20°31’ W of TN
AC = 4’ W
2012 – 1998 = 14 years
14 × 4’ W = 56’ W
MD = 20° 31’ W + 56’ W
= 20° 87’ W of TN
= 21° 27’ W of TN
MB = 21° 27’ + 57°
= 77° 27’ – 79° 27’

Position/co-ordinates
Co-ordinates are a set of two numbers that indicate the exact position of any point on Earth. Latitude is the co-ordinate that specifies the north– south position of a point on the Earth’s surface. Longitude is the coordinate that specifies the east–west position of a point on the Earth’s surface.
Co-ordinates are useful as they tell us exactly where a place or landform is.

Example of position/co-ordinates
If you wanted to locate a house and only had the co-ordinates 35°S 29°E, you would have to search an area of 6 084 km2. You would need to be more specific when giving the location of a place.
Note the following about position/co-ordinates:

• On a 1:50 000 map the numbers in the top left corner indicate latitude and longitude. Latitude and longitude are measured in degrees and minutes.
  
• Each line drawn on a map is 1’ of latitude or longitude (‘ is the sign for a minute).
• Each fifth minute on a map is labelled. This helps you to count accurately.
• Latitude minutes increase as you move south (down the map). Longitude minutes increase as you move east (to your right along
• the map).
• The correct format for writing position is as follows:
  _____° ____,___’ S
  _____° ____,___’ E

Method for finding the position of an object
You can calculate the position of spot height 501 using the diagram in Figure 5.3.1.

Learn the format for writing position. Note that you always write latitude N or S first.

Use the following steps
Step 1: Write the format for position like this (leaving the blanks for you to fill your answer in later).
_____° ____,___’ S
_____° ____,___’ E
Step 2: Work out the degrees for latitude and longitude for the map.
They are written in the top left-hand corner of the map. Write the degrees down on your format.
24° ____,___’ S
31° ____,___’ E
Step 3: Work out the minutes for latitude and longitude. The spot height is in the 10′ block for latitude (not the 11′ block for latitude) and the 28′ block for longitude (not the 29′ block for longitude). Write the minutes down in the blank spaces of your position format.
24° 10′,___’ S
31° 28′,___’ E
Step 4: Measure the distance between 10′ and 11′ and divide it by 2. Then make a mark on the line between 10′ and 11′ where 3 cm is.

Step 5: Measure the distance between 28′ and 29′ and divide it by 2.
Make a mark on the line between 28′ and 29′ where 4,7 cm is. Step 6: The space between 10′ and 11′ is divided into 10 decimal places, in other words, 10,1′; 10,2′; 10,3′; 10,4′; 10,5′; 10,6′; 10,7′; 10,8′ and 10,9′.

As the spot height is in the bottom half of the block, we are only concerned with the 10,5’ to 10,9’ part of the block.
Once you have divided the block in half, divide the half you are interested in equally with 4 lines. This can be done freehand (without a ruler), but judge carefully so that the spaces are equal.
Step 7: The space between 28′ and 29′ is divided into 10 decimal places, in other words, 28,1′; 28,2′; 28,3′; 28,4′; 28,5′; 28,6′; 28,7′; 28,8′ and 28,9′.
As the spot height is in the right-hand half of the block, we are only concerned with the 28,5′ to 28,9′ part of the block.
Once you have divided the block in half, divide the half you are interested in equally with 4 lines. This can be done freehand (without a ruler), but judge carefully so that the spaces are equal.
Steps 6 and 7 are shown below:

Step 8: Line up your ruler with the spot height and the line for latitude (on the left of the map). Make a mark. Read off the decimal place for latitude and write it down on your position format. 24° 10,8′ S or 24° 10,9′ S (both answers are acceptable)
Step 9: Line up your ruler with the spot height and the line for longitude (at the top of the map). Make a mark. Read off the decimal place for longitude and write it down on your format.
Your answer is now complete:
24° 10,8′ S or 24° 10,9′ S (both answers would be accepted)
31° 28,8′ E

-After 10,9’ it becomes 11’, so you can never have 10,10’.
After 28,9’ it becomes 29’, so you can never have 28,10’
-Make sure your ruler is straight by lining up the markings on the ruler with any of the lines on the map.
Example
The position of spot height
501 in Figure 5.1 is…
A. 31° 28,8’ S; 24°10,8’ E
B. 31° 28,8’ E; 24° 10,8’ S
C. 24° 10,8’ S; 31° 28,8’ E
D. 24°11,8’ S ; 31° 29,8’ E
(The correct answer is C.)
-In the exam, position is often asked in the multiple-choice section of the paper. Be careful, as an answer may look correct – but longitude is written first! You should know this is wrong because latitude is always written first!

Map sheet references/map code
The map sheet reference is the title of the map and refers to the area that the map covers. The sheet reference links one South African map to all the maps of South Africa.
An example of a map sheet reference is 3318CD. The digits (numbers) and letters have specific meaning:
The numbers in the map sheet reference refer to the intersection of the lines of latitude and longitude (3318CD). The first two numbers refer to latitude (33) and the last two numbers refer to longitude (18). The letters CD refer to the blocks.
The area within these lines of latitude and longitude is divided into four squares, labelled A, B, C and D (big blocks).
Each of the big blocks is then subdivided into four smaller squares, also labelled A, B, C and D (small blocks).

Remember, latitude (N or S) is always written first.
In the exam, you may be asked two types of questions based on the map sheet reference:

• Typical question 1: What is the map sheet reference of the map? (You will find the answer at the top of the map in front of the name of the place shown on the map.)
• Typical question 2: Name the map sheet reference in any direction from the given map sheet reference. (This is explained in Examples 1 and 2 below.)

Example 1
For the map title 3318CD Cape Town:

Give the map sheet reference to the east of 3318CD.

• The block to the east of 3318CD (light shading) is block C (darker shading).
• This block is still within the 33° latitude and 18° longitude area, so the numbers (3318) stay the same.
• But it is now in big block D, so the letters change to DC.
• The map sheet to the east of 3318CD is 3318DC.

Example 2
For the map title 3318CD Cape Town.

Give the map sheet reference to the south of 3318CD.

• The block to the south of 3318CD (light shading) is the block B (darker shading).
• This block is out of the 33° latitude area and in the 34° latitude area. However, the block is still within the 18° longitude area. The latitude changes but the longitude stays the same (3418).
• It is now in big block A, so the letters change to AB.
• The map sheet to the south of 3318CD is 3418AB.

Always look for a grid showing the map sheet reference at the bottom of a map sheet. It may also provide you with information to help you answer other questions.

When answering this type of question, take note of the following:

• If you are asked for the grid reference north and you go north (up) out of the big block, the latitude must decrease by 1°.
• If you are asked for the grid reference south and you go south (down) out of the big block, the latitude must increase by 1°.
• If you are asked for the grid reference east and you go east (right) out of the big block, the longitude must increase by 1°.
• If you are asked for the grid reference west and you go west (left) out of the big block, the longitude must decrease by 1°.

Vertical exaggeration
In mapwork, we draw a cross section (view from the side) of an area or landform to better understand what the area or landform looks like.
A cross section is when we ‘cut’ through a landform, to see what it looks like from the side. Figure 5.3.2 below shows a cross section through a tap.

To draw a cross section of a landform, we need to look at the contour lines.
These are the brown lines we see all over a topographic map. Contour lines show the height of the area. Along one contour line, the height is the same.
Study Figure 5.3.2 to understand what is meant by the term cross section.

Figure 5.3.3 below is a contour map of a landform. If we had to draw a cross section from A to B on Figure 5.3.3 we would first imagine we were walking from A to B:

• Looking at the heights on the contours we see we are walking uphill;
• Then we go downhill a little bit;
• Then uphill again; and
• Then downhill to B.

A cross section is drawn on a graph. We use the vertical axis to show the height and horizontal axis to show the distance.
If the vertical and horizontal scales are the same, it is not easy to see the differences in slope.
Figure 5.3.4 below shows the cross section from A to B (in Figure 5.3.3).
Because the vertical and horizontal scales are the same (1:10 000), we do not really get a good idea of the differences in slope.

To overcome this problem, we exaggerate (make it more obvious or clear) the profile vertically by using a different vertical scale from the horizontal scale. This is shown in Figure 5.3.5.
Figure 5.3.5 uses a vertical scale where 1 cm represents 20 m for the same map. It is much easier to see the changes in slope along the profile.

We therefore say the cross-section has been exaggerated, and we need to calculate how many times it has been made steeper or exaggerated. This is called the vertical exaggeration.

Remember the horizontal scale lies the same way as the horizon.

Method for calculating vertical exaggeration
Follow these steps:
Step 1: Change the vertical scale from a word scale to a number scale. The vertical scale will be given to you in the question, e.g. 1 cm = 40 m.
You must have the same units on both sides of the vertical scale in order to write it as a number scale. We need to convert 40 m into cm. To do this you multiply the 40 m by 100 (1 m = 100 cm).
Our scale becomes 1 cm = 4 000 cm or   1
4 000
Step 2: The horizontal scale is already written as a number scale. On a topographic map the scale is 1:50 000 and on an orthophoto the scale is 1:10 000.
Step 3: Write both scales as fractions and divide the vertical scale by the horizontal scale:
VE =    1     ÷     1
4000     50 000
Step 4: Now ‘tip and times’ the two fractions. You do this by swopping the top and bottom numbers of the horizontal scale fraction and then multiplying the top of each fraction together and the bottom of each fraction together.
VE =    1      × 50 000
4000           1
Step 5: You are now left with one fraction. Divide the top by the bottom.
(Use your calculator to divide 50 000 by 4 000.)
VE = 50 000
4 000
An easy way to remember that the horizontal scale goes on top is that ‘H’ comes before ‘V’ in the alphabet.
Step 6: Write the answer as follows: VE = 12,5 times
This means the cross section has been exaggerated 12,5 times in order to see the changes in the landscape more easily.

Worked example 1
Calculate the vertical exaggeration for a cross section drawn on a topographical map with a vertical scale of 1 cm = 50 m.
Answer
VE = VS ÷ HS
VS: 1 cm = 50 m
1 cm = 50 × 100 cm = 5000 cm
VS 1:5 000
VS   1
5 000
HS 1:50 000
HS     1
50 000
VE =   1      ÷    1
5 000   50 000
VE =    1      × 50 000
5 000         1
VE = 50 000
5 000
VE = 10 times

Always write the formula VE = VS ÷ HS as this will earn you a mark.

Worked example 2
Calculate the vertical exaggeration for a cross section drawn on an orthophoto map with a vertical scale of 1 cm = 25 m.
Answer
VE = VS ÷ HS
VS: 1 cm = 25 m
1 cm = 25 × 100 cm = 2 500 cm
VS 1:2 500
VS    1
2 500
HS 1:10 000
HS     1
10 000
VE =   1     ÷    1
2 500    10 000
VE =    1      × 10 000
2 500          1
VE = 10 000
2 500
VE = 4 times

Intervisibility
Intervisibility is used to determine whether one place is visible from another place, in other words, whether you can see one place from another place.
Method to determine intervisibility
To work out whether two places are intervisible, follow these steps:
Step 1: Draw a line joining the points between the two places.
Step 2: Look to see if the line you have drawn cuts through any part of the cross section. If it does cut through, then there is no intervisibility between the two points. If it does not cut through, then there is intervisibility between the two points.

In the exam, you may be given a cross section and asked to determine if two places are intervisible.

Example 1
In Figure 5.3.6 below, is point Q intervisible from point P?

The answer is that there is no intervisibility between P and Q, as the line cuts through the cross-section (goes through the mountain). This means you cannot see point Q from point P, and you cannot see point P from point Q.

Example 2
In Figure 5.3.7 below, is point X intervisible from point Q?

The answer is there is intervisibility between X and Q, as the line does not cut through the cross-section. This means you can see point X from point Q, and you can see point Q from point X.

Activity 5.8
Refer to the topographical map and orthophoto of Nelspruit at the back of this study guide to answer the following questions:

1. Calculate the area covered by block B3 on the Nelspruit topographical map in kilometres squared. (5)
2. Calculate the magnetic bearing for 2012 from trig. beacon 101 (C3) to spot height 676 (C4) on the topographical map. Show all steps followed (calculations). Marks will be allocated for calculations. (10)
3. Calculate the gradient between trig. beacon 101 in block C3 and spot height 676 in block C4. (5)
   [20]

Check how well you can do mapwork calculations by completingactivity 5.8.

Answers to activity 5.8

1. Area = length × breadth
   = (3,7 cm × 0,5) km × (3,3 cm × 0,5) km
   = 1,85 km × 1,65 km
   = 3,05 km²(5)
2. Magnetic declination: 15°02′ west of true north
   Annual change: 03′ E
   Number of years: 2012 – 1986 = 26 years
   26 × 3′ = 78′ E = 1° 18′ E
   Magnetic declination: =15°02′ W – 1°18′ E
   = 14° 62′ W – 1° 18′ E
   = 13°44′ W
   Magnetic bearing = True bearing + Magnetic declination
   = 102° + 13° 44′ W
   = 115° 44′ (10)
3. Gradient =   Height   = H
   Distance    D
   H = 754,4 – 676 = 78,4 m
   D = 5,6 cm × 500 = 2 800 m
   G = 78,4 : 2 800
   78,4 78,4
   G = 1:35,73 (5)
   [20]

5.4 Application of theory to a topographic map and an orthophoto

In this section we look at how the theory that you have learnt in previous chapters can be applied to a topographic map or an orthophoto.
5.4.1 Climatology
In the exam, you may be asked questions such as:

1. Which slopes are the warmest?
   Determine which slope faces north. North-facing slopes are the warmest.
2. Which slopes are the coldest?
   Determine which slope faces south. South-facing slopes are the coldest.
3. Why are there more houses and plantations on a slope in a valley?
   Determine which slope faces north. North-facing slopes are the warmest and people choose to live there. Plants also grow better there.
4. Where will the thermal belt occur?
   Determine where the valley is and where halfway up the valley would be.
   This is where you will find the thermal belt (temperature inversion).
5. Where will frost occur?
   Determine where the bottom of the valley is. Frost pockets occur at the bottom of a valley.
6. Does the area experience high rainfall?
   Determine the amount of cultivated land, the number of perennial rivers (flow all year round) and the total number of rivers in an area (drainage density). High-rainfall areas have lots of cultivated land, many perennial rivers indicate high drainage density.
7. Does the area experience low rainfall?
   Determine the amount of cultivated land, the number of perennial rivers (flow all year round) and non-perennial rivers (only flow in the rainy season), and the total number of rivers in an area (drainage density). Low-rainfall areas have very little cultivated land; few, if any, perennial rivers and many nonperennial rivers; and few rivers, indicating low drainage density.
8. Does the area experience seasonal rainfall?
   Determine the number of non-perennial streams, dams, furrows and whether the cultivated land is next to a river. Seasonal rainfall areas have mostly non-perennial rivers, many dams, furrows and the cultivated land is next to the perennial rivers.

Questions 6, 7 and 8 also test some geomorphology knowledge.
5.4.2 Geomorphology
In the exam, you may be asked questions such as:

1. In which direction does the river flow?
   Determine the height of the river at each point where it starts and ends on the map. A river flows downhill, so it flows from the highest point to the lowest point.
   Look at the tributaries that join the main river. The direction in which tributaries join the main river follows the same direction in which the river is flowing.
2. Identify the drainage pattern of the river.
   Determine the pattern of the river system. Is it a dendritic, radial or trellis pattern? Refer to Figure 2.2.3 C to E on page 31 showing drainage patterns in Chapter 2: Geomorphology.
3. Determine the underlying rock structure of an area.
   Determine the drainage pattern in the area. The causes of a drainage pattern tell you the kind of rock in the area. For example, if there is a dendritic drainage then the underlying rocks are either horizontal sedimentary rock, igneous or metamorphic rock. Refer to Figure 2.2.3 C to E showing drainage patterns in Chapter 2: Geomorphology.
4. In which stage (course) is the river?
   Determine the steepness of the sides of the valley and the steepness of the river course. A very steep valley is V-shaped and has a steep gradient.
   This is where the upper course of a river is found. In contrast, if you find a wide floodplain (flat area alongside a river), meanders, marshes or vleis, and oxbow lakes, this is where the lower course of a river is found.

5.5 Geographical information systems – GIS

GIS is an organised collection of computers, computer programmes, geographic data and people. This definition gives you the components that make up GIS: People who know how to use computers (hardware) and programmes (software) to provide information (from geographic data) are able to solve a problem or answer a specific question.

Key concepts

Concept	Definition
Components of GIS	Hardware (computers), software (computer programmes), data (information), people, procedures (how to solve a problem or answer a question), network (where to get the information from).
Spatial data	Spatial data refers to the position of an object, in other words, its co-ordinates. For example, the spatial data for a tree could be: 29°30,3′ S; 19°10,8′ E
Attribute data	Attribute data is information that describes or gives the characteristics of an object. For example, the attribute data for a tree could be: It is an acacia tree, which is 5 m tall.
Vector data	Spatial data stored in the form of co-ordinates, shown as point, line or polygon features.
a) Point features	Point features on a map include spot height, buildings and trig stations.
b) Line features	Line features on a map include rivers, roads and walls.
c) Polygon features	Polygon features on a map include cultivated land, built-up areas and dams.

In a mapwork exam, you may be asked to identify a point, line or polygon feature on a map. Look at the conventional signs shown in the block (referred to in the question).

• Point features are indicated by a circle (e.g. spot height), triangle (e.g. trig. station), square (e.g. building, post office), rectangle (e.g. factory) or a single object (wind pump, dipping tank).
• Line features are indicated by a straight line (e.g. farm boundary, wall) or a curved line (e.g. rivers, roads and railways).
• A polygon feature is any sign that takes up more space than a single feature, for example, a dam, cultivated land, built-up area or golf course.

If you know and understand this definition of geographic information systems (GIS), then you will be able to answer the relevant questions in the mapwork section of the final exam. Use mobile notes to help you learn these key concepts.

Buffering	To demarcate (mark off) an area around an object. The marked-off area is the buffer zone. Buffer zones often protect people from living in a dangerous area. For example, along a river people should live above the 50-year flood line. The 50-year flood line is the height below which the river floods. The area below the 50-year flood line is the buffer zone for this area. If you live in the buffer zone your home is likely to be affected when the river floods. If you take notice of the buffer zone and live above the 50-year flood line, your home is likely to be safe when the river floods. Figure 5.5.1 below shows how point, line and polygon features have buffer zones placed around them.
Raster data	Spatial data stored in the form of pixels. Pixels are similar to the blocks found on a topographic map (e.g. block A3). The size of the pixel (block) will determine in how much detail an area will be shown. Smaller pixels show more detail. Larger pixels show less detail.
Remote sensing	Taking a picture of something from far away, for example from a satellite.
Spatial resolution	How clear and easy the detail is to see.
Data or thematic layering	When different kinds of information are placed one on top of the other to see the overall picture. For example, on the Nelspruit map, the layers of data needed to draw block D1 are: Vegetation Contour lines Roads Power lines Built-up areas Water
Data sharing	Data sharing is the practice of making data used for scholarly research available to other investigators.
Data standardisation	It is the process of achieving agreement on common data definitions, representation and structures to which all data layers must conform.
Data security	This means protecting a database from destructive forces and the unwanted actions of unauthorised users. This may be done by encryption, firewall or password.
Data querying	This is a process used to retrieve or get data from the data base.
Statistical analysis	The collection of methods used to process large amounts of data and report overall trends.

Activity 5.9
Refer to the topographic map 2530BD Nelspruit and the orthophoto map extract at the back of this study guide to answer the following questions.

1. Underline the correct term that matches the description below:
   1. Data that refers to the actual position of an object is vector/raster data. (1 × 2 = 2)
   2. Data that is stored in pixels is vector/raster data. (1 × 2 = 2)
2. Refer to block B1 on the 2530BD Nelspruit topographic map. Give an example from this block of the following:
   1. Point feature (1 × 2 = 2)
   2. Line feature (1 × 2 = 2)
   3. Polygon feature (1 × 2 = 2)
3. List any four layers that were used to draw this topographic map. (4 × 2 = 8)
   [18]