Page 67 - Geography_n_Environment

Then, move the folded paper to the left along the linear scale by
aligning point B with zero (the red mark will be on the left side of the
linear scale). Observe the number in the linear scale that is nearest

or aligned to the red mark and label it as shown in Figure 7(b). From
Figure 7(a), the number on the left side of point B is 2 and the unit
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is km, so it is 2 km. From Figure 7(b) the nearest number to the red
mark is 500 and the unit is m, so it is 500m. Therefore, the ground
distance from point A to B is 2 kilometres and 500 metres.
(1)
1000 (1)
Metre 500 0 1 2 3 Kilometre
Metre 1000 500 0 1 2 3 Kilometre

A Folded paper 2 B

A Folded paper 2 B

(a)

1000 (2)
Metre 1000 500 0 (2) 1 2 3 Kilometre

Metre 500 0 1 2 3 Kilometre
A Folded paper 2 B
500
A Folded paper (3) 2 B
500 (b)
(3)
Figure 7: Convert the map distance to ground distance when point B is
between two numbers on the right side of the linear scale

(d) Using a ratio scale, measure the map distance from points A
GSPublisherVersion 0.6.100.100
to B on the folded paper with a ruler. For example, if, the map
distance between points A and B is 5 centimetres and the ratio
scale is 1:50000, the real distance on the ground from point A
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to point B can be calculated as follows:

distance on the ground (Km) =
Distance on a map (cm) x Scale denominator

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GEOGRAPHY AND THE ENVIRONMENT-STD 4.indd 60 21/11/2024 16:58