NCERT Solutions for Class 11 Geography Practical Work in Geography I Chapter 5: Topographical Maps

Chapter at a glance

Exercise Questions

Question 1 (i)

What are topographical maps?

Answer

Topographical maps are large-scale maps that show in detail both natural features (relief, drainage, vegetation) and cultural features (settlements, roads, railways, canals) of an area, using contours and conventional signs. In India they are prepared by the Survey of India.

Large-scale maps showing detailed natural and cultural features of an area using contours and conventional signs.

Question 1 (ii)

Name the organisation which prepares the topographical maps of India.

Answer

The Survey of India, Dehradun.

Question 1 (iii)

Which are the commonly used scales for mapping our country used by the Survey of India?

Answer

1 : 1,000,000 (India and adjacent countries series), 1 : 250,000 (degree sheets), 1 : 50,000 and 1 : 25,000 (large-scale sheets).

1 : 1,000,000, 1 : 250,000, 1 : 50,000 and 1 : 25,000.

Question 1 (iv)

What are contours?

Answer

Contours are imaginary lines joining all the points of equal elevation above mean sea level. They are used on topographical maps to show the relief and slope of the land.

Imaginary lines joining places of equal height above mean sea level.

Question 1 (v)

What does the spacing of contours indicate?

Answer

Spacing of contours indicates the slope: closely spaced contours indicate a steep slope; widely spaced contours indicate a gentle slope; evenly spaced contours show a uniform slope.

The slope: close spacing means steep slope, wide spacing means gentle slope.

Question 1 (vi)

What are conventional signs?

Answer

Conventional signs are standardised symbols, signs and colours used on maps to represent features such as roads, railways, settlements, rivers, vegetation and boundaries. They are internationally or nationally accepted, so maps can be read easily by everyone.

Standard symbols and colours used on maps to represent features like roads, settlements, rivers and boundaries.

Question 2 (i)

Write short notes on Contours.

Answer

Contours are imaginary lines on a map joining places of equal height above mean sea level. They are drawn at a fixed vertical interval, the contour interval (usually 20 m on 1 : 50,000 sheets).

Features

1. They show the height and slope of land; closely spaced contours show steep slopes and widely spaced contours show gentle slopes.
2. Contours of different heights never cross each other (except in the case of an overhanging cliff) and never split.
3. They are generally drawn in brown on topographical sheets, with values written on them.
4. Patterns of contours show landforms: concentric closed contours with increasing values inward show a hill; a V-shape pointing towards higher ground shows a valley; a V pointing to lower ground shows a spur; contours merging indicate a cliff or waterfall.

Contours join places of equal height at a fixed interval; their spacing shows slope, they never cross, and their patterns reveal landforms like hills, valleys, spurs and cliffs.

Question 2 (ii)

Write short notes on ‘Marginal Information’ in Topographical sheets.

Answer

Marginal information is the information printed in the margins of a topographical sheet, which helps in reading and interpreting the map:

• Topographical sheet number (e.g. 63K/12), its location and extent in latitude and longitude;
• Grid references and the names of districts/states covered;
• Scale (R.F. and graphical) and contour interval;
• North direction, magnetic variation;
• Conventional signs and legends used;
• Year of survey and publication, and the agency (Survey of India).

Information in the sheet margins — sheet number, latitudes/longitudes, area covered, scale, contour interval, north direction, legend/conventional signs and survey year.

Question 2 (iii)

Write short notes on The Survey of India.

Answer

The Survey of India is the national survey and mapping organisation of India, established in 1767, with headquarters at Dehradun. It conducts topographical surveys and prepares topographical maps of the entire country at various scales (1 : 1,000,000 to 1 : 25,000), using a systematic numbering scheme. It also does geodetic surveys, aerial photography and digital mapping, and its maps are the basis for planning and development.

India’s national mapping agency, founded in 1767 and based at Dehradun, which surveys and publishes topographical maps of the country at various scales.

Answer

Map interpretation is the reading and analysis of a topographical map to understand the physical and cultural landscape of an area and the relationship between them.

Procedure

1. Study the marginal information — sheet number, location, scale, contour interval, north direction and the legend of conventional signs.
2. Divide the map into broad parts (e.g. by grid squares or quarters) for systematic study.
3. Relief and drainage: study contours to identify landforms (hills, plateaus, valleys) and slopes; study rivers, their direction of flow and drainage patterns.
4. Land use / vegetation: identify cultivated land (yellow), forests (green), scrub, wasteland.
5. Means of transport and communication: roads, railways, footpaths, telegraph lines, post offices.
6. Settlements: type (clustered, dispersed, linear) and distribution.
7. Occupations: infer from land use and features (agriculture, quarrying, fishing).
8. Relate the features to each other — e.g. settlements along rivers or roads, cultivation on plains.

Map interpretation is reading a topographical sheet to understand its physical and cultural landscape; study marginal information, then relief, drainage, land use, transport, settlements and occupations, and relate them.

Answer

Cultural features are man-made. While interpreting them, I would seek information on:

1. Settlements: their type (rural/urban), pattern (compact, scattered, linear) and distribution. Derived from red symbols for houses and village names; e.g. on sheet 63K/12, Kachhwa is a compact settlement with a market, police station and post and telegraph office, while villages on the right bank of the Ganga are small and scattered.
2. Transport and communication: metalled and unmetalled roads, cart tracks, footpaths, railways, ferries, telegraph lines and post offices. E.g. a metalled road runs through Kachhwa; people of Bhatauli cross the Ganga by ferry (6 boats).
3. Land use and occupations: yellow colour shows cultivated land (agriculture is the main occupation); brick kilns and stone quarries indicate other occupations.
4. Irrigation and water management: canals, dams (e.g. Lower Khajuri Dam), tanks and wells.
5. Public services: schools, dispensaries, police stations, rest houses, places of worship.

These are derived from conventional signs, colours and names printed on the sheet, and by relating them to relief and drainage (e.g. dense settlements on level plains near roads and rivers; sparse settlements in forested hills).

Seek settlement types and patterns, transport and communication, land use and occupations, irrigation, and public services — derived from conventional signs, colours and names, e.g. compact Kachhwa with market and PTO, scattered villages, ferry at Bhatauli, cultivated land in yellow.

Answer

See the drawn symbols: dash-dot line (international boundary), BM with height (bench mark), red blocks (villages), red double-line road (metalled road), dashed path with bridge, temple/mosque/church symbols, and a thick line with cross-ticks (railway).

Exercise A (contour map)

Question A1

Name the geographical feature formed by contours.

Answer

The closed contours enclose a large flat-topped area, with steep sides on some edges. This forms a plateau (a flat-topped highland).

A plateau (flat-topped high land).

Question A2

Find out the contour interval in the map.

Answer

The contour values are not printed on the diagram, so the actual contour interval cannot be read from it. On a real sheet, contour interval = difference between two successive contour values (e.g. 20 m on 1 : 50,000 sheets).

Contour values are not shown, so the interval cannot be determined from the figure (it is the difference between successive contour values).

Question A3

Find out the map distance between E and F and convert it into ground distance.

Answer

Given: scale 1 cm represents 2 km.

Measured on the printed figure, E to F is about 1.8 cm.

Ground distance km

(The measured value can differ slightly with the printed size of the book.)

About 1.8 cm on the map, i.e. about 3.6 km on the ground.

Question A4

Name the type of slope between A and B; C and D and E and F.

Answer

• A and B: contours are fairly widely and evenly spaced — a gentle (uniform) slope.
• C and D: contours are very close together — a steep slope.
• E and F: contours are moderately spaced — a gentle slope.

A–B: gentle uniform slope; C–D: steep slope; E–F: gentle slope.

Question A5

Find out the direction of E, D and F from G.

Answer

• E is to the west of G.
• D is to the north of G.
• F is to the south-west of G.

E: west; D: north; F: south-west of G.

Exercise B (sheet 63K/12, Kachhwa area)

Question B1

Convert 1:50,000 into a statement of scale.

Answer

1 cm represents 50,000 cm = 0.5 km.

1 cm represents 0.5 km (500 m).

Question B2

Name the major settlements of the area.

Answer

Kachhwa (the largest, with market, police station and post and telegraph office), Majhwan, Bajahan, Baraini, Bhatauli, Prem ka Pura, Sobesar, Kanak Sarai, Beropur.

Kachhwa (main), Majhwan, Bajahan, Baraini, Bhatauli, Prem ka Pura and Sobesar.

Question B3

What is the direction of flow of the river Ganga?

Answer

In this extract the Ganga flows from the north-west to the south-east.

From north-west to south-east.

Question B4

At which one of the banks of river Ganga, Bhatauli is located?

Answer

Bhatauli lies to the south-west of the river. For a river flowing towards the south-east, this is the right bank.

On the right bank of the Ganga.

Question B5

What is the pattern of rural settlements along the right bank of river Ganga?

Answer

The settlements on the right bank (Bhatauli, Jaunsara, Bedauli Khurd, Bedauli Kalan, Kakarha) are small and scattered (dispersed), located a little away from the river because of floods.

Small, scattered (dispersed) settlements.

Question B6

Name the villages/settlements where Post Office is located?

Answer

Kachhwa (Post and Telegraph Office — PTO), Baraini, Bhatauli, Majhwan, and a village in the north-west near Gobra.

Kachhwa (PTO), Baraini, Bhatauli, Majhwan and near Gobra.

Question B7

What does the yellow colour in the area refer to?

Answer

Cultivated (agricultural) land.

Question B8

What means of transportation is used to cross the river by the people of Bhatauli village?

Answer

The map shows a ferry (6 boats) at Bhatauli Ghat.

Boats — a ferry (6 boats) at Bhatauli Ghat.

Exercise C (sheet 63K/12, Dānti Reserved Forest area)

Question C1

Give the height of the highest point on the map.

Answer

The highest spot height shown is 297 m (near the telegraph line in the south-west).

297 metres.

Question C2

River Jamtihwa Nadi is flowing through which quarter of the map?

Answer

The south-eastern quarter.

Question C3

Which is the major settlement located in the east of the Kuardari Nala?

Answer

Kotwa, which has a post office and a forest chauki, lies just east of the Kuardari Nala along the main road.

Kotwa.

Question C4

What type of settlement does the area have?

Answer

The area is mostly forested and hilly, so the settlements are small, scattered (dispersed) rural settlements (hamlets), apart from a small compact settlement at Kotwa along the road.

Small, scattered (dispersed) rural settlements.

Question C5

Name the geographical feature represented by white patches in the middle of Sipu Nadi.

Answer

White patches in the river bed represent sand (sand bars/dry sandy river bed).

Sand bars (sandy patches in the river bed).

Question C6

Name the two types of vegetation shown on part of the topographical sheet.

Answer

Fairly dense mixed jungle and open scrub (also fairly dense bamboo).

Fairly dense mixed jungle and open scrub.

Question C7

What is the direction of the flow of the Kuardari?

Answer

The Kuardari Nala flows from the south to the north, towards the Lower Khajuri Dam (with a fall of 16 m on its way).

From south to north.

Question C8

In which part of the sheet area is Lower Khajuri Dam located?

Answer

In the northern (north-central) part of the sheet.

Topic checklist

• Topographical maps and the Survey of India
• Contours: properties, slopes and landforms
• Conventional signs
• Marginal information and map interpretation
• Reading extracts of sheet 63K/12

Total questions answered: 33 of 33