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Social sciences

Geography

Grade 8

Mapwork

Module 15

Conventional signs used on 1:50000 maps

Conventional signs used on 1:50 000 maps

These signs form part of the “language” of topographic maps. They are provided in the key / reference below the map and are used the world over. You should get to know and understand them thoroughly.

Map symbols for cultural phenomena (phenomena created by people)

The signs used on maps are selected to be immediately recognisable for what they represent. Cultural phenomena that are shown are buildings, towns, power lines (in black) dams, canals (in blue) trees, plantations and fields (in green). These symbols are exaggerated on the map, because they would be too small to be represented if their actual sizes were represented.

Map symbols for natural phenomena

The most important natural phenomena are mountains, hills, valleys and plains. These phenomena, however, have to be deduced from contour lines and are not represented by specific symbols. We’ll be studying contour lines shortly.

Another important natural phenomenon shown on topographic maps is the drainage of any particular area. This is observed by examining the rivers and their tributaries, which are indicated in blue on a topographic map.

On topographic maps, perennial rivers are indicated by means of continuous blue lines, while the (seasonal) rivers of areas with low or seasonal rains are indicated with dotted lines).

The direction of the flow of a river also provides important information about the higher and lower parts of an area:

Water ALWAYS flows from high to lower places.

Tributaries flow into the main stream in the direction of the flow.

Example:

Observe the way in which dam walls are constructed across a river bed. The dam wall is always downstream.

Example:

Height prediction on a topographical map

Height can be indicated on a map in several ways.

The trigonometric beacon is shown by means of a triangle with the beacon’s number to the right of the triangle, as well as its exact height above sea level, in metres, below the triangle. On a map, these beacons are usually shown to be on the highest parts.

Example:

SPOT HEIGHTS on a map are shown by means of black dots and the height value is printed alongside it.

● 1419

Example

The vertical difference in height between two high points is obtained by subtracting the lower measurement from the higher one,e.g.: A = 800 m; B = 200 m; Difference in height = 600 m.

Contour lines are unbroken brown lines marked in number values.

Contour lines connect all places that have the same height above sea level. The figure printed on the line indicates the actual height in metres.

The difference in height between two consecutive contour lines is known as the contour interval or vertical interval and is always 20 m. Each 100 m is indicated with a thicker contour line.

The further apart the contour lines are, the more level (flat) the landscape.

The closer to one another the contour lines are, the steeper and more mountainous the landscape.

Where there are perpendicular cliffs, contour lines touch. Remember, however, that contour lines never cross one another.

By examining the contours, you will be able to determine the direction in which a river is flowing and to identify certain forms of the landscape.

ACTIVITY 1:

[LO 1.4]

1. Explain what is represented by the following map symbols:

a)

b)

c)

d)

e)

2. Carefully study the area between the N1 and the R81 (SE corner of the map). Name at least six map symbols that occur in this area.

3. Are there any indications that the railway is electrified?

4. What type of communication lines join Beaufort West with the outside world?

5. What map symbols will you find at the following coordinates?

a) 32º17’06”S ; 22 37’15”E

b) 32º19’11”S ; 22 34’04”E

c) 32º20’49”S ; 22 34’09”E

d) 32º19’26”S ; 22 37’28”E

6. What is the average height above sea level in the vicinity of the rifle range(32º19’06”S ; 22º35’37”E)?

7. What is the height of the highest trig. beacon on the topographic map?

8. What is the contour interval on this map?

9. Determine the vertical difference in length between Lammertjiesleegte (32º20’52”S; 22º33’37”E) and trig. beacon 148.

10. Is there any relation between the route of the railway and the relief of the area?

11. What is the name of the perennial river in this area?

12. In which direction does this river in no. 11 flow?

13. Do you think there is a flood danger in this area? Explain.

14. What indications are there on this map that stock farming occurs in this area?

15. What do you think is the purpose of the furrows indicated on the map?

16. What can you derive from the rainfall in this area?

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:
  • identifies and selects a variety of
geographical and environmental sourcesthat are relevant to the research;
  • interprets information from maps and
atlases, as well as graphic and statisticalsources;
  • calculates distance from maps and
compares it to real distance;
  • identifies physical features and features
created by people and aerial photographsand maps.

Memorandum

ACTIVITY:

  1. Graves.
  1. Excavations.
  2. Provincial border.
  3. Power lines.
  4. Trigonometrical beacon
  1. Faint roads, rivers, buildings, railway lines, power lines, dams, windmill, forested area, cultivated lands, trigonometrical beacons, spot height, rows of trees.
  2. None.
  3. Roads, railway line.
  1. Railway line.
  1. Faint footpaths.
  1. Cultivated lands.

Built-up area. (Mgquba).

  • ±550 – 600 m.
  • ρ 318 (32°45'50"S, 26°52'0"E) is 653,6 m high.
  • 20 metres.
  • Hillcrest = 540 m.

ρ 84 = 624,2.

624,2 – 540 = 84,2 metres.

  • In general the railway lines follow the contour lines more than roads do.
  • Tyume.
  • Comes from the north and leaves the map in the south-west.
  • Yes, when it rains a lot the areas where the 2 main streams converge, can be flooded.
  • Irrigation dams and cultivated lands close to rivers.
  • Trees and bushes.
  • Moderate to reasonably high rainfall.

Questions & Answers

How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
Devang Reply
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
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Source:  OpenStax, Geography grade 8. OpenStax CNX. Sep 11, 2009 Download for free at http://cnx.org/content/col11036/1.1
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