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Directorate: Curriculum FET

SUBJECT and GRADE GEOGRAPHY – GRADE 11

TERM 1 Week 6: Lesson 6

TOPIC Oblique and vertical aerial photographs; orthophoto maps;

AIMS OF LESSON • To strengthen your knowledge, understanding and interpretation of the role of oblique and vertical aerial

photographs in the development of orthophoto maps and topographic maps.

RESOURCES

Paper based resources Digital resources

•Lesson on pages 2 - 5

•Learner tasks on page 6

•Textbook: Aerial photographs

and orthophoto maps

Video: Aerial photographs and orthophoto maps - Mindset Learn https://www.youtube.com/watch?v=XZMwrMLjjF0&list=PLOaNAKtW5HLRPOxnhJTRAHtCK3Evnqy

sB&index=13

Video: YouTube

https://www.youtube.com/watch?v=CVl79ojfzCA

INTRODUCTION You should know from previous lessons:

Grade 10: Types of aerial photographs; Characteristics, advantages and disadvantages of orthophoto maps.

CONCEPTS AND SKILLS You must know:

• Characteristics, advantages and disadvantages

of oblique aerial photographs.

• Characteristics, advantages and disadvantages

of vertical aerial photographs.

• Characteristics, advantages and disadvantages

of orthophoto maps.

You must be able to:

• apply knowledge and concepts on various

geographic sources.

• read and interpret sources such as oblique and

vertical aerial photographs as well as orthophoto

maps.

ACTIVITIES/

ASSESSMENT

Complete the:

• activity for this lesson on page 6.

• additional activities in your textbook.

CONSOLIDATION You must study this topic by asking key Geographic questions such as: What is it? Why is it there? What does it

look like? What is the effect? How can the effect be managed e.g. pollution?

VALUES It is important to understand that photographs and maps can provide rich sources of information about places

and/or geographic phenomena in different parts of the world.

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Study this topic with the following questions in mind!

TOPIC: Oblique and vertical aerial photographs; orthophoto maps; (LESSON 6)

What are the three

types photographs

according to the angle

at which they were

captured?

• Horizontal (terrestrial) photographs

• Oblique photographs (these include high oblique and low oblique)

• Vertical aerial photographs

What are the

advantages of each

type of photograph?

• Horizontal photographs

show the shape and

vertical dimensions of

geographical features.

• Oblique photographs

show the landscape from

above but they

show familiar side views

and make features easier

to identify than vertical

aerial photographs.

• Vertical photographs

show all features in the

correct spatial

relationship to each

other. Because only the

top view can be seen,

features may

not be so easy to identify.

How do you identify

landforms and features

on an oblique or

vertical photograph?

We can use the following

elements to help us identify

landforms and features on

aerial photographs:

• Shape and pattern

• Tone

• Texture

• Shadow

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Shape and pattern

We can identify human-

made structures such as

buildings and roads have

geometric shapes and

distinct boundaries while

natural features like

mountains, rivers, lakes, etc.

have irregular and uneven

shapes.

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Tone The tone of features can be

light or dark.

The reflectivity of the object,

the weather, the angle of the

sunlight on an object, and on

moisture content of the

surface all play a role in

determining the tone of the

feature.

Smooth surfaces, bare

ground, winter vegetation,

muddy water and new crops

all have a light tone.

Irregular surfaces, vegetation,

clear water, mature crops

and ploughed fields all have

a dark tone.

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Texture Texture is the description of

the smoothness or coarseness

of a feature in a photograph.

Terms used to describe

texture include:

• coarse or fine

• smooth or rough

• even or uneven

• speckled

• granular

• linear

• woolly

Texture also describes the

terrain surface

roughness.

Crops have a speckled

appearance while ploughed

fields are striped and

darker.

Orchards have coarse and

grid- like texture while

vineyards have a finer and

striped texture.

Plantations appear mottled

and coarse.

Pine plantations look stippled

and finer.

Blue gum plantations look

granular, coarser.

Younger plantations appear

striped.

.

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Shadow Objects can be recognised

by the shadows they cast.

Shadows that objects cast

can help you to determine

the time of day and position

of the sun.

Inward cast shadows show

depth while outward cast

shadows show height.

How to identify features

on orthophoto maps

An orthophoto map is a

black and white

photographic image to

which cartographers

have added helpful

information such as contours,

spot heights and street

names. This makes them

easier to identify.

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LEARNER TASK:

Question 1

(Adapted from Platinum Geography Grade 11)

The questions are based on the photograph and map below.

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1.1 List FOUR commercial functions of aerial photography.

1.2 Identify the features labelled A to E.

1.3 State TWO advantages of vertical aerial photographs.

1.4 State TWO disadvantages of vertical aerial photographs

Question 2

(Adapted from Spot on Geography Grade 11)

Study the photographs and answer the questions that follow:

2.1 Explain the difference oblique aerial photographs and vertical aerial photographs.

2.2 State ONE disadvantage of oblique aerial photographs.

2.3 State THREE disadvantage of oblique aerial photographs.

2.4 State the type of oblique aerial photograph at C and D and identify the major feature found on the oblique

aerial photographs.

Question 3

(Adapted from Focus Geography Grade 11)

Study the photograph and map and answer the questions below:

3.1 What is the land use for in these areas?

3.1.1 L11 and 12

3.1.2 P13 and 14

3.1.3 O11 and P11

3.1.4 E8

3.1.5 A10

3.1.6 T3 and U3

3.2 How does the texture of the area in P13 and P14 indicate that this is not a wheat field or an orchard?

3.3 Arrange these buildings in order of height, starting with the tallest. J15; I5; L11

3.4 Find the two rows (letters of the alphabet) that show the N2 national road.

3.5 What is the very dark area in parts of T7-10 and U7-10?

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3.6 Squares H to M6-14 are the core of Knysna’s central business district (CBD). Find two ways in which the CBD

core looks different from a residential area

3.7 What is the transport function at R3 and R4?

3.8 Sport in Knysna. In which squares is there evidence of the following sport and recreation?

3.8.1 Tennis

3.8.2 Rugby or soccer

3.8.3 Cricket

3.8.4 Sailing

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Question 4

The questions are based on maps of Rustenburg West and the orthophotos below.

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4.1 Identify the following features on the orthophoto map: • 7 • 9 • 12

4.2 Locate the area marked 3 on the orthophoto map.

4.3 This area is an informal settlement. Give ONE piece of evidence from the orthophoto map to support this

statement.