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Map scale

Lessons 8 · 1 lessons · P. Gulyamov, R. Qurbonniyozov, M. Avezov, N. Saidova. Geography (Introductory Course of Physical Geography), Grade 5. Revised and expanded 5th edition. “Mitti yulduz”, Tashkent, 2020
8

Map scale

Textbook: §8, pp. 30–32
GoalKnow the kinds of scale and calculate distances using map scale.
New words
scale · masshtabnumerical scale · sonli masshtabnamed (verbal) scale · nomli masshtablinear (bar) scale · chiziqli masshtab
Explanation

Scale is a fraction showing how many times a distance on the ground is reduced on a drawing or map. For example, if 800 m is drawn as 4 cm, it is reduced 20 000 times and the scale is 1 : 20 000. Scale is written in three ways: numerical (1 : 100 000), named (1 cm to 1 km) and linear (a straight line divided into equal parts). To change a numerical scale into a named one, we remove the last five zeros: centimetres become kilometres, because 1 km = 100 000 cm. So at 1 : 15 000 000, 1 cm stands for 150 km, and at 1 : 120 000 000, 1 cm stands for 1200 km. We measure the map distance with a ruler or compasses and multiply by the scale; measuring with compasses against the linear scale is the most convenient.

Worked examples
At 1 : 500 000, 1 cm stands for 5 km (500 000 : 100 000 = 5). If the map shows 4 cm, the real distance is 4 × 5 = 20 km.
If two cities are 300 km apart and the map shows 6 cm, then 1 cm stands for 300 : 6 = 50 km, so the scale is 1 : 5 000 000.
Class activity

“Scale workshop”: draw a plan of the classroom or schoolyard on squared paper with a chosen scale (for example 1 square = 1 m), then find distances on your partner’s plan.

Practice
1
What is scale? What kinds are there?
2
At 1 : 200 000, how many km does 1 cm stand for?
3
The map scale is 1 : 1 000 000. Two cities are 5 cm apart on the map. How many km is the real distance?
4
Why do we need scale to draw the Earth’s surface on paper?