The reading, analysing and interpretation of topographical maps

SOCIAL SCIENCES: Geography

Grade 7

MAP WORK

Module 10

The reading, analysing and interpretation of topographic maps

The ability to use and interpret maps is an important part of a person’s geographical skills. When using a map you should remember that:

– the real picture on scale is reduced;

– the phenomena and patterns are seen as if shown from above, looking down on a landscape;

– symbols are used to show characteristics and phenomena.

Different kinds of maps are drawn for different functions.

Activity 1:

To identify a variety of maps as geographical and environmental resources

[LO 1.1]

See how many different kinds of maps you can identify in your atlas. Write down the names underneath one another, and indicate each one’s most important function.

Activity 2:

To interpret maps containing a variety of information

[LO 1.2]

1. Different scales and calculating distance

You already know that a map is a REDUCTION of reality, as seen from above. To reduce a map in this way, you have to use a certain SCALE.

The scale of a map MUST be indicated at the bottom of a map. Different kinds of scales can be used:

On a line scale you can measure the distance between two places directly.

Ratio scale, e.g. 1:50 000 which means that 1 centimetre (or whatever length unit is used) on the map is equal to 50 000 centimetres (the same length unit) in reality.

If two places on the map are 4 cm away from each other, you will first have to make a calculation to determine the real distance, i.e.4 cm × 50 000 = 200 000 cm

= 200 000 cm ÷ 100 000

= 2 km

Word scale, e.g. 1 cm represents 20 km. If the distance between two places on the map is 3 cm, you will also have to do a calculation first:3 cm × 20 = 60 km

One of or all the different kinds of scales can be indicated on a specific map.

Activity 3:

To learn how to use line scale

[LO 1.3]

1. Measure the length and width of your classroom and then draw a floor plan. Use a scale of 2 cm to represent 1 metre.

Draw another floor plan of your classroom, but now use a scale of 1 cm to represent 1 metre.

2. The two drawings of the same classroom differ in size because there is a difference in the SCALES used for drawing them.

3. Measure something else at school that is quite a bit bigger than your classroom, for example the hall or the rugby field. Draw it on the same size paper that you used to draw your classroom. To be able to do this, you need to have more metres represented in a centimetre for your plan/map than was the case when you drew the classroom. The scale will therefore differ now because you have to draw a larger area on paper of the same size.

Indicate the scale as a line scale on your map.

Activity 4:

To calculate distance on an atlas map and a globe

[LO 1.3]

Open your atlas at a map of Southern Africa. Determine the real distance between the following places. Measure along a straight line (as the crow flies).

a) Cape Town – East London ___________km

b) Durban – Johannesburg __________________km

c) Pretoria – Kimberley _________________ km

d) Kimberley – Cape Town _________________ km

2. Determine the distances between the following places on a globe:

a) Durban and Sydney _______________ km

b) Cape Town and Rio de Janeiro _____________ km

c) Paris and New York ____________ km

d) Tokyo and Moscow_______ km

2. Map symbols and map keys

Included in this module is a 1:50 000 topographic map of Ceres, as well as a complete list of map symbols. These map symbols should be studied to enable you to identify the different characteristics when you study the map of Ceres.

You need not necessarily do this exercise about Ceres. Ask your teacher to order a map of your own city or town and district in time to enable you to study your familiar surroundings as indicated on the map. You’ll also be surprised at how much information it contains. Study the way in which mountains with different forms, mountain ravines, valleys, etc. are indicated.

WRITE TO: THE STATE PRINTER

PRIVATE BAG X85

PRETORIA

and order an official 1:50 000 map of the area in which your town or city is situated. You’ll be surprised at how little it costs.

Assessment

Memorandum

Activity 1:

Activity 4:

1. a) ± 925 km

± 500 km

± 500 km

± 840 km

2. Determine the distances between the following places on a globe:

a) Durban and Sydney 8 250 km

b) Cape Town and Rio de Janeiro 4 750 km

c) Paris and New York 5 250 km

d) Tokyo and Moscow 7 250 km