Topographical Maps: Colours, Symbols, Scale, Distance and Direction, Part 2: Distance, area and direction: visual lesson, ICSE Class 10 Geography (H.C.G. Paper 2)

Lesson

Measuring on the sheet

With the scale you can turn map measurements into ground measurements. In the ICSE paper you only measure straight-line (direct) distance, you find area only from complete grid squares, and you give direction with the eight points of the compass. We practise all three on the imagined practice sheet.

In this lesson you will

Calculate the straight-line distance between two places using the scale
Calculate the area of a region from full grid squares only
State the direction of one place from another using the eight points of the compass

Imagined practice sheet, not a real place and not a Survey of India sheet
Measure	How	Unit
Distance	Straight line, then use the scale	km
Area	Count full 1 km squares	sq km
Direction	Eight compass points	N, NE, E, SE, S, SW, W, NW

Concept

Straight-line distance

To find the direct (straight-line) distance between two places: join them with a straight line; measure it in cm with a ruler (or on a strip of paper against the linear scale); multiply by the scale (here 0.5 km per cm). On the extract the police station A and the temple B are about 1.8 cm apart on a printed sheet, so the ground distance is about 0.9 km. Roads and rivers are not measured here, only straight lines.

Imagined practice sheet, not a real place and not a Survey of India sheet

Worked example

Worked example: Sonakhedi to the temple

Problem. On a printed sheet the centre of Sonakhedi (S) and the temple (T) are about 7.9 cm apart. Find the ground distance.

Step 1. Scale: 1 cm to 0.5 km.

Step 2. Distance = 7.9 × 0.5 = 3.95 km, about 4 km.

Check with the grid. S and T differ by 3.25 km east-west and 2.25 km north-south, so the distance is √(3.25² + 2.25²) = 3.95 km.

Imagined practice sheet, not a real place and not a Survey of India sheet

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