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Social sciences

Geography

Map work

Grade 9

Module 12

Recognizing topographic features on vertical aerial photographs and orthophoto maps

It requires a great deal of practice to be able to recognize features on vertical photographs. You have had some experience of this in Grade 8. If you are unable to recognize something at first glance, you need to ask particular questions to obtain background information from a topographic map:

In which part of the country is the area?

What type of climate and vegetation occur in this area?

What farming activity is practiced in the area? – etc.

Answers to such questions can be obtained from various sources, such as an atlas, for instance.

The most important indicators on photographic images are the following:

Form

Geometric forms indicate objects made by people. Railway lines are shown as fine lines with gradual curves and junctions; roads are broader and have right angle junctions. Cultural features are even and follow a definite pattern. Natural features, like rivers, which have meandering confluences, are irregular.

Size

Different buildings may have the same shape, but size will indicate the difference between a hut, a house and a factory. Road widths usually are quite clearly identifiable.

Shadows

High, relatively thin features like church spires, telephone poles, lighthouses and factory chimneys may be too small to observe from above. Their shadows will give an indication of their location and shape.

Long shadows, however, hide certain other features. For this reason, photographs should not be taken too early or too late in the day. The best time for taking aerial photographs is between 10 o’clock in the morning and 2 o’clock in the afternoon.

Shadows also indicate direction and this helps the reader with the orientation of the map. In the Southern Hemisphere, shadows usually lie southward .

Activity 1: [lo 1.4]

The sun rises in the east and sets in the west. Vertical aerial photographs should be taken between two hours before and two hours after 12 o’clock. In which direction will the shadows fall during this time?

In the morning:

In the afternoon:

Social Sciences

GEOGRAPHY

MAP WORK

Grade 9

Module 11

Shading

The shading of a photograph depends on the height of the sun and the amount of light that is reflected by the photographed object. The following examples are useful guidelines for testing information involving shading:

Dark Dark Explanation
Uneven surfaces. Uneven surfaces. Smooth surfaces reflect light, while uneven surfaces absorb light.
Clear water. Murky water. Light penetrates clear water, but is reflected by clouded or murky water.
Stagnant water. Rippling waters. Waves/ripples cause dispersed reflection of light..
Wet soil. Dry soil. Wet soil absorbs more light.
Plant cover. Bare ground. Vegetation absorbs light (sand appears white.)
Ploughed lands. Fallow lands. Ploughing breaks up the reflective surface into smaller areas.
Established crops. Newly-sown crops. Larger crops absorb more light.
Rivers. Roads. Tarred roads seem white because they reflect light (in spite of seeming dark when we look at them).

Texture

Texture indicates land use and ground cover patterns. Citrus orchards, for instance, show a rougher texture than fields of maize. Sand looks smooth and shrubby ground seems woolly.

Some examples of land use are:

Land use Features
Cultivated fields crops have a variegated appearanceharvested wheat fields or fields of feed crops are light and smoothFields on which threshing machines are used show clearly visible lines of dotsploughed fields appear striped and are darker
Orchards and vineyards they usually have a chequered appearanceorchards are roughly texturedvineyards show a finer texture and sometimes appear striped
Forests and plantations seem dotted or variegatedhave a recognisable linear pattern
Pasturage seems to have small spots or is dottedanimal paths appear as fine white lines that converge at a drinking place

Easily identifiable features:

Schools usually have sports fields.

A golf course has fairways and greens.

Urban settlements reveal residential differentiation:

buildings situated in close proximity indicate the city centre or low-income housing;

buildings on large plots indicate high-income housing.

Airports have easily recognisable runways.

Mining areas are revealed by conspicuous mine dumps and excavations.

Telephone lines and power lines are recognized by the regularity of their shadows.

Assessment

Learning Outcomes(LOs)
LO 1
Geographical EnquiryThe learner will be able to use enquiry skills to investigate geographical and environmental concepts and processes.
Assessment Standards(ASs)
We know this when the learner:
1.2 asks questions that are relevant for identifying sources;
1.3 draws conclusions and makes analyses to obtain information from sources such as photographs, maps, atlases, graphs and statistics;
1.4 correlates information from different sources;
1.7 reports on knowledge that they have obtained through research, making use of different sources of information.
LO 2
Geographical Knowledge and UnderstandingThe learner will be able to demonstrate geographical and environmental knowledge and understanding.
We know this when the learner:
2.2 identifies ways in which Science and Technology have contributed a positively and negatively influence to development (people and resources.)

Memorandum

ACTIVITY1:

Mornings - slightly south-west

Afternoons - slightly south-east

Questions & Answers

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are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
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CYNTHIA
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s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
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s. Reply
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Ebrahim
in general
s.
Graphene has a hexagonal structure
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Cied
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In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
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Source:  OpenStax, Geography grade 9. OpenStax CNX. Sep 14, 2009 Download for free at http://cnx.org/content/col11057/1.1
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