Representation of Geographical Features ICSE Class 8: Contours and Toposheets

What Representation of Geographical Features is about

Weightage: CISCE publishes no question paper, marking scheme or chapter weightage for Class VIII Geography: your school sets and marks the exam. Representation of Geographical Features sits in the Representation of Geographical Features theme of the CISCE Curriculum for Upper Primary Classes (VI-VIII).Source: CISCE Curriculum for Upper Primary Classes (VI-VIII), RDCD 2016

Key concepts

Contours and contour interval

A contour is an imaginary line on a map joining all places that have the same height (elevation) above mean sea level. On toposheets contours are drawn in brown.
Key terms:

• Contour value: the height written on a contour line, in metres.
• Contour interval (vertical interval, VI): the difference in height between two successive contours. It is the same throughout one map. Example: contours labelled 100, 120, 140 show an interval of 20 m.
• Horizontal equivalent (HE): the horizontal distance on the ground between two points, measured on the map and converted using the scale.
• Spot height: a dot with a number showing the exact height of a point.
• Bench mark (BM): a height marked on a permanent object, found by survey.
• Triangulated height: a height point fixed by a triangulation survey, shown by a small triangle.

Rules about contours:
1. Contours never cross each other (except at an overhanging cliff, rarely shown).
2. Contours close on themselves, either on the map or beyond its edge.
3. Closely spaced contours mean a steep slope; widely spaced contours mean a gentle slope.
4. Where contours merge into one thick line, the slope is vertical, as at a cliff.

Worked example

(2 marks) Contours on a map are labelled 260, 280, 300 and 320 m. (a) What is the contour interval? (b) Estimate the height of a point exactly midway between the 280 and 300 m contours.

Try it first, then show the solutionSolution

1. (a) Contour interval = 280 - 260 = 20 m - 1 mark.
2. (b) Midway between 280 and 300 m: about (280 + 300) / 2 = 290 m - 1 mark.

Answer: (a) The contour interval is 20 m. (b) The point is about 290 m above sea level (an estimate, assuming an even slope between the contours).

Slopes: steep and gentle

Slope is the angle of the ground surface. On a map, slope is judged from the spacing of contours.

• Steep slope: contours are close together, because the height changes a lot over a short horizontal distance.
• Gentle slope: contours are far apart, because the height changes little over a long horizontal distance.
• Uniform (even) slope: contours are equally spaced.

Gradient expresses steepness as a ratio:
Gradient = vertical interval / horizontal equivalent, written as '1 in x', where x = HE / VI (both in the same units).
Example: a rise of 200 m over 2,000 m of horizontal distance gives a gradient of 1 in 10 (for every 10 m you move across, you rise 1 m).
Uses: steep slopes are difficult for farming and roads (roads zigzag up them); gentle slopes suit farming, settlements and transport.

Worked example

(3 marks) On a map of scale 1:50,000, point A is on the 100 m contour and point B on the 300 m contour. The distance between them on the map is 4 cm. Find the gradient from A to B.

Try it first, then show the solutionSolution

1. VI = 300 - 100 = 200 m - 1 mark.
2. HE: 1 cm = 50,000 cm = 500 m, so 4 cm = 2,000 m - 1 mark.
3. Gradient = VI / HE = 200 / 2,000 = 1 / 10, that is 1 in 10 - 1 mark.

Answer: The vertical interval is 200 m and the horizontal equivalent is 2,000 m, so the gradient is 200/2,000 = 1 in 10.

Hills and plateaus through contours

Hill (conical hill): a raised area with a summit. Shown by roughly circular contours, one inside another, with values increasing towards the centre. The innermost contour or a spot height marks the top. If contours are close, the hill is steep; if far apart, gentle.

Plateau (tableland): a large raised area with a fairly flat top and steep sides. Shown by contours that are close together at the edges (steep sides) and a wide space with few or no contours on top (flat surface). The top contour encloses a broad area.

How to tell them apart: a hill has many contours rising to a small summit; a plateau has its contours crowded at the edges and an empty, wide top.

Other features you may see: a valley is shown by V-shaped contours pointing towards higher ground (the opposite of a spur, where the V points towards lower ground).

Worked example

(2 marks) How would you recognise a plateau from its contours?

Try it first, then show the solutionSolution

1. Contours crowded together at the edges, showing steep sides - 1 mark.
2. A wide area at the top with few or no contours, showing a flat surface - 1 mark.

Answer: A plateau is shown by contours that are close together around its edges, indicating steep sides, enclosing a broad area at the top with few or no contours, indicating a fairly flat surface.

Ridge, gap, saddle, col and pass

Ridge: a long, narrow stretch of high ground with steep sides. Shown by elongated (long, oval) contours, with values increasing towards the centre line, often with more than one summit.

Along a ridge there may be lower points between summits:

• Saddle: a broad, gentle depression between two summits on a ridge, shaped like a horse's saddle. On the map, the contours of the two summits are separate, with a wide gap between them at the same level.
• Col: a narrow, sharper depression between two summits, smaller and steeper than a saddle.
• Gap: a steep-sided break or opening through a ridge, often cut by a river, which may be used by roads or railways.
• Pass: a gap, col or saddle through a mountain range that provides a route across it. Passes have been important for trade and invasion; examples in India include the Khyber Pass (now in Pakistan) and the Nathu La in Sikkim.

On a toposheet, look for a lower area where the contours of two higher areas come close but do not join; a road or footpath often crosses at that point, showing a pass.

Worked example

(3 marks) Distinguish between a saddle and a col. Why are passes important?

Try it first, then show the solutionSolution

1. Saddle: a broad, gentle depression between two summits on a ridge - 1 mark.
2. Col: a narrow, sharper and steeper depression between two summits - 1 mark.
3. Passes provide routes across mountains for roads, trade and movement - 1 mark.

Answer: A saddle is a broad, gently curving low area between two summits on a ridge, while a col is a narrower, sharper and steeper depression. A pass, which may be a gap, col or saddle, is important because it gives a route across a mountain range for roads, railways, trade and travel.

Settlement patterns

A settlement is a place where people live, from a single hut to a large city.

By duration:

• Temporary settlements: occupied for a short time, such as by herders who move with their animals in different seasons or by people living in forests who shift with farming (shifting cultivation).
• Permanent settlements: occupied all the time, with lasting houses, such as farming villages, towns and cities.

By pattern (shape):
1. Nucleated (compact or clustered): houses are built close together around a centre such as a temple, well, market or crossroads. Found in fertile plains with good water supply, and where people group together for safety. On a toposheet, many house symbols are crowded in a small area.
2. Dispersed (scattered): houses are spread out, often separated by fields, forests or rough land. Found in hilly, forested or dry areas, or where farms are large. On a toposheet, single huts are scattered widely.
3. Linear: houses are arranged in a line along a road, railway, river, canal, coast or valley. On a toposheet, house symbols line up along a road or stream.
Factors that influence patterns: relief, water supply, soil fertility, transport routes, climate and security.

Worked example

(3 marks) Name three settlement patterns and state where each is likely to be found.

Try it first, then show the solutionSolution

1. Nucleated: fertile plains with water; around a centre - 1 mark.
2. Dispersed: hilly, forested or dry areas; large farms - 1 mark.
3. Linear: along roads, rivers, railways, canals or coasts - 1 mark.

Answer: Nucleated settlements, with houses clustered together, are found in fertile plains with good water supply. Dispersed settlements, with scattered houses, occur in hilly, forested or dry areas. Linear settlements, with houses in a line, develop along roads, rivers, railways, canals or coasts.

Reading a toposheet

Steps for interpreting a toposheet:
1. Read the marginal information: sheet number, scale, contour interval, and the legend of conventional signs and symbols.
2. Scale: on a 1:50,000 sheet, 1 cm = 0.5 km, so 2 cm = 1 km. The grid squares (eastings and northings) are usually 2 cm apart, so each square represents 1 km by 1 km = 1 square km.
3. Relief: study contours, spot heights and triangulated heights to identify hills, plateaus, ridges, valleys and slopes.
4. Drainage: rivers and streams in blue; note the direction of flow (from higher to lower contours), and whether streams are perennial (flowing all year) or seasonal/dry.
5. Vegetation and land use: green colour for forests or wooded areas, yellow wash for cultivated land, white for land not under cultivation.
6. Settlements and communication: settlement symbols (red for permanent huts and buildings), roads, railways, footpaths, and patterns of settlements.
7. Conventional signs and colours: brown for contours, blue for water, black for railways and boundaries, red for roads and settlements, green for vegetation, yellow for cultivation.
Relate features: for example, settlements on gentle slopes and near water; roads following valleys and passing through gaps.

Worked example

(3 marks) On a toposheet of scale 1:50,000, (a) what distance on the ground is shown by 6.4 cm? (b) What area is covered by one 2 cm by 2 cm grid square?

Try it first, then show the solutionSolution

1. Scale: 1 cm = 50,000 cm = 0.5 km - 1 mark.
2. (a) 6.4 cm x 0.5 km = 3.2 km - 1 mark.
3. (b) 2 cm = 1 km, so the square is 1 km x 1 km = 1 square km - 1 mark.

Answer: (a) 6.4 cm represents 6.4 x 0.5 = 3.2 km on the ground. (b) Each grid square is 1 km by 1 km, that is 1 square km.

Representation of Geographical Features in real life

Each concept, met in an everyday situation. Read the situation, answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Topics in this chapter

• Contours, Contour Interval, Slopes and Gradient
• Hills, Plateaus, Ridges, Passes and Settlement Patterns

Representation of Geographical Features: key facts

Scale 1:50,000

$1cmonmap=50,000cm=0.5km;2cm=1km$

Ground distance = map distance x 0.5 km.

Contour interval

$Contourinterval=differenceinheightbetweentwosuccessivecontours$

Same throughout one map.

Gradient

$Gradient=VI/HE=1in(HE/VI)$

VI and HE in the same units (metres).

Grid square area

$2cmx2cmsquareon1:50,000=1kmx1km=1sqkm$

Contour spacing

$Closecontours=steepslope;widecontours=gentleslope;mergedcontours=cliff$

Representation of Geographical Features: map work

The places on the official CISCE map list for this chapter. Find each one on an outline map of India and practise marking it.

How the school exam asks Representation of Geographical Features

The question patterns to expect, and the method that works for each.

Tricks to remember Representation of Geographical Features

Short memory aids. Say each one aloud once, then use it on a question the same day.

• Spacing rule

  'Close lines climb, far lines flat.'

  Use it when: Steep versus gentle slopes.

• Saddle vs col

  A saddle is broad like a horse's back; a col is narrow like a coat collar.

  Use it when: Telling the two apart.

• Toposheet colours

  'Brown Brings height, Blue Brings water, Green Grows trees, Yellow Yields crops, Red Roads and homes.'

  Use it when: Conventional colours.

Representation of Geographical Features: exam-level solved questions

Ordered from exam level to HOTS. Cover the solution, write your own, then compare step by step.

Case-study practice (Section B style)

Read the situation, then answer every part. In a school exam set on the board pattern this is a 7-mark question split into 2 + 2 + 3 marks.

Where the marks are

How a typical answer is split into step marks. Show every step: a right final answer alone rarely earns full marks.

Where students lose marks in Representation of Geographical Features

The slips examiners see most often, and what to write instead.

• ✗Mistake: Mixing up units in gradient calculations

  VI in metres, HE in km or cm.

  ✓Do this: Convert both to metres before dividing.

  Usually costs: 1-2 marks.

• ✗Mistake: Reading close contours as gentle

  Thinking 'close' means small.

  ✓Do this: Close contours = big change in height over a short distance = steep.

  Usually costs: 1 mark.

• ✗Mistake: Writing the answer without units

  Hurry.

  ✓Do this: Always write m, km or sq km, and express gradient as '1 in x'.

  Usually costs: Half to 1 mark.

• ✗Mistake: Calling every low point on a ridge a pass

  Not checking for a route.

  ✓Do this: A pass is a low crossing used as a route; name a saddle or col by its shape.

  Usually costs: 1 mark.

Practice questions on Representation of Geographical Features

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

1. Q1 · 1 mark · MCQExam level

   On a 1:50,000 map, 2 cm represents:
   (a) 500 m
   (b) 1 km
   (c) 2 km
   (d) 5 km

   Hint

   1 cm = 0.5 km.

   Answer

   (b) 1 km.

2. Q2 · 1 mark · MCQHarder exam level

   A narrow, sharp depression between two summits on a ridge is called a:
   (a) saddle
   (b) col
   (c) plateau
   (d) spur

   Hint

   Narrower than a saddle.

   Answer

   (b) col.

3. Q3 · 1 mark · Very short answerExam level

   Find the ground distance represented by 9 cm on a 1:50,000 toposheet.

   Hint

   Multiply by 0.5 km.

   Answer

   9 x 0.5 = 4.5 km.

4. Q4 · 2 marks · Very short answerHarder exam level

   A road rises 60 m over a horizontal distance of 1.2 km. Find its gradient.

   Hint

   Convert km to m.

   Answer

   HE = 1,200 m; gradient = 60/1,200 = 1 in 20.

5. Q5 · 2 marks · Very short answerHarder exam level

   A road has a gradient of 1 in 25. How many metres does it rise over 1 km of horizontal distance?

   Hint

   1,000 / 25.

   Answer

   1,000 / 25 = 40 m.

6. Q6 · 2 marks · Very short answerHarder exam level

   Why do contours never cross each other?

   Hint

   One place, one height.

   Answer

   Because each point on the ground has only one height; if two contours crossed, the crossing point would have two different heights, which is impossible (except at a rare overhanging cliff).

7. Q7 · 2 marks · Very short answerExam level

   Distinguish between temporary and permanent settlements with one example each.

   Hint

   Duration.

   Answer

   Temporary settlements are occupied for short periods, such as herders' seasonal camps; permanent settlements are lived in all the time, such as farming villages and towns.

8. Q8 · 2 marks · Very short answerHarder exam level

   What is the difference between a spot height and a bench mark?

   Hint

   Where is it marked?

   Answer

   A spot height is a dot on the map with a number showing the height of that point; a bench mark is a height that is also engraved on a permanent object on the ground, such as a building or pillar, fixed by survey.

9. Q9 · 3 marks · Short answerExam level

   State three factors that lead to a nucleated settlement.

   Hint

   Land, water, safety.

   Answer

   Flat, fertile land suitable for farming; a reliable water source such as a well, tank or river; and the need for security or a common centre such as a temple or market.

10. Q10 · 3 marks · Short answerHOTS / competency

    A student says a hill and a plateau look the same on a map because both have closed contours. Explain how to tell them apart.

    Hint

    Look at the top.

    Answer

    Both have closed contours, but a hill has contours continuing inwards to a small summit, often with a spot height, while a plateau has contours crowded only at its edges and a wide area on top with few or no contours, showing a flat surface.

11. Q11 · 4 marks · Long answerHOTS / competency

    Suppose you must choose a site for a new village on a toposheet. List three things you would look for, giving a reason for each.

    Hint

    Slope, water, transport, safety.

    Answer

    (1) Gentle slopes (widely spaced contours), so building and farming are easy. (2) A perennial water source nearby, such as a river or tank, for drinking and irrigation. (3) Access to a road or railway for transport. Also, a site above the flood level of the river (not on the lowest contours next to it) to stay safe in floods.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1. 1.What colour are contours on a toposheet?Show answer

   Brown.

2. 2.On a 1:50,000 sheet, what does 1 cm represent?Show answer

   0.5 km (500 m).

3. 3.What does widely spaced contours show?Show answer

   A gentle slope.

4. 4.What is a ridge?Show answer

   A long, narrow stretch of high ground with steep sides.

5. 5.What pattern do houses along a road form?Show answer

   A linear settlement.

6. 6.Find the gradient: VI 50 m, HE 1 km.Show answer

   50/1,000 = 1 in 20.

Quick revision checklist

The night before the exam: can you do each of these without looking?

• ☐Contour: line joining places of equal height; brown; never cross; close = steep, far = gentle, merged = cliff.
• ☐Contour interval: height difference between successive contours; same on one map.
• ☐Scale 1:50,000: 1 cm = 0.5 km; 2 cm = 1 km; grid square 2 cm = 1 sq km.
• ☐Gradient = VI / HE = 1 in (HE/VI), same units.
• ☐Hill: concentric rings to a summit; plateau: crowded edges, flat top; ridge: long contours; saddle broad, col narrow, gap a break, pass a route.
• ☐Settlements: temporary or permanent; nucleated (clustered), dispersed (scattered), linear (along roads, rivers, coasts).

Representation of Geographical Features: frequently asked questions