CHAPTER 5 : Topographical Maps NCERT SOLUTION CLASS 11TH PRACTICAL WORK IN GEOGRAPHY | EDUGROWN NOTES

Short Answer Type Questions:

Q1.What are the features of contours?
Answer:
Some basic features of contour lines are:

• A contour line is drawn to show places of equal heights.
• Contour lines and their shapes represent the height and slope or gradient of the landform.
• Space between contour lines represents slope. Closely spaced contours represent steep slopes while widely spaced contours represent gentle slope.
• When two or more contour lines merge with each other, they represent features of vertical slopes such as cliffs or waterfalls.
• Two contours of different elevation usually do not cross each other.

Q2.Explain how do we interpret a topographical sheet?
Answer:
It is essential to have knowledge of map language and sense of direction are essential in reading and interpreting topo-sheets. We must first look for the northline and the scale of the map and orient ourselves accordingly. We must have a thorough knowledge of the legends / key given in the map depicting various features. All topo-sheets contain a table showing conventional signs and symbols used in the map. We must be acquainted with conventional symbols, signs and colours.

Q3.Under which heads is a topographical sheet interpreted? Explain each in short.
Answer:
A topographic sheet is usually interpreted under the following way:

• Marginal Information: It includes the topographical sheet number, its location, grid references, its extent in degrees and minutes, scale, the districts covered, etc.
• Relief of the Area: The general topography of the area is studied to identify different landforms along with peaks, ridges, spur and the general direction of the slope.
• Drainage of the Area: We also need to interpret the important rivers and their tributaries and the type and extent of valleys formed by them, the types of drainage pattern, i.e. dendritic, radial, ring, trellis, internal, etc.
• Land Use: It includes the use of land under different categories like Natural vegetation and forest which part of the area is forested, whether it is dense forest or thin, and the categories of the forest found there like Reserved, Protected, Classified / Unclassified.
• Transport and Communication: The means of transportation include national or state highways, districts roads, cart tracks, camel tracks, footpaths, railways, waterways, major communication lines, post offices, etc. topographical sheet presents each of these.
• Settlement: Settlements are studied under rural settlements and urban settlements.
• Occupation: The general occupation of the people of the area may be identified with the help of land use and the type of settlement.

Q4.What factors determine the site of settlements?
Answer:
Various factors determine the site of settlements like

• Source of water
• Provision of food
• Nature of relief
• Nature and character of occupation
• Defence.

Q5.Write a short note on map interpretation.
Answer:
Map interpretation involves the study of factors that explain the causal relationship among several features shown on the map. For example, the distribution of natural vegetation and cultivated land can be better understood against the background of landform and drainage. Likewise, the distribution of settlements can be examined in association with the levels of transport network system and the nature of topography.

Long Answer Type Questions:

Q1.Explain the steps involved in drawing, a Cross-section from their contours in different topographical landforms.
Answer:
The following steps may be followed to draw cross-sections of various relief features from their contours:

• Draw a straight line cutting across the contours on the map and mark it as XY.
• Take a strip of white paper or graph and place its edge along the XY line.
• Mark the position and value of every contour that cuts the line XY.
• Choose a suitable vertical scale, e.g. V2 cm =100 metres, to draw horizontal lines parallel to each other and equal to the length of XY. The number of such lines should be equal or more than the total contour lines.
• Label the appropriate values corresponding to the contour values along the vertical of the cross-section. The numbering may be started with the lowest value represented by the contours.
• Place the edge of the marked paper along the horizontal line at the bottom line of the cross-section in such a way that XY of the paper corresponds to the XY of the map and mark the contour points.
• Draw perpendiculars from XY line, intersecting contour lines, to the corresponding line at the cross-section base.
• Smoothly join all the points marked on different lines at the cross-section base.

Q2.Under which heads are topographical maps explained?
Answer:
A topographic sheet is usually interpreted in the following way:

• Marginal Information: It includes the topographical sheet number, its location, grid references, its extent in degrees and minutes, scale, the districts covered, etc.
• Relief of the Area: The general topography of the area is studied to identify different landforms along with peaks, ridges, spur and the general direction of the slope. These features are studied under the following heads:
  • Hill: With concave, convex, steep or gentle slope and shape.
  • Plateau: Whether it is broad, narrow, flat, undulating or dissected.
  • Plain: Its types, i.e. alluvial, glacial, karst, poastal, marshy, etc.
  • Mountain: General elevation, peak, passes, etc.
• Drainage of the Area: We also need to interpret the important rivers and their tributaries and the type and extent of valleys formed by them, the types of drainage pattern, i.e. dendritic, radial, ring, trellis, internal, etc.
• Land Use: It includes the use of land under different categories like Natural vegetation and forest, which part of the area is forested, whether it is dense forest or thin, and the categories of forest found there like Reserved, Protected, Classified / Unclassified.
• Transport and Communication: The means of transportation include national or state highways, district roads, cart tracks, camel tracks, footpaths, railways, waterways, major communication lines, post offices, etc. topographical sheet presents each of these.
• Settlement: Settlements are studied under the following heads:
  • Rural Settlements: The types and patterns of rural settlements, i.e. compact, semi-compact, dispersed, linear, etc.
  • Urban Settlements: Type of urban settlements and their functions, i.e. capital cities, administrative towns, religious towns, port towns, hill stations, etc.
• Occupation: The general occupation of the people of the area may be identified with the help of land use and the type of settlement. For example, in rural areas the main occupation of majority of the people is agriculture; in tribal regions, lumbering and primitive agriculture dominates and in coastal areas, fishing is practised. Similarly, in cities and towns, services and business appear to be the major occupations of the people.

Q3.Explain about identification of cultural features from topographical sheets
Answer:
Settlements, buildings, roads and railways are important cultural features shown on topographical sheets through conventional signs, symbols and colours. The location and pattern of distribution of different features help in understanding the area shown on the map.
Types of Settlements: Four types of rural settlements may be identified on the map:

1. Compact
2. Scattered
3. Linear
4. Circular

Urban centres are distinguished as:

• Cross-road town
• Nodal point
• Market centre
• Hill station
• Coastal resort centre
• Port
• Manufacturing centre with suburban villages or satellite towns
• Capital town
• Religious centre

Site of settlements:
It should be closely examined with reference to the contour and drainage map. Density of settlement is directly related to food supply. Sometimes, village settlements form alignments, i.e. they are spread along a river valley, road, embankment, coastline – these are called linear settlements. In the case of an urban settlement, a cross-road town assumes a fan-shaped pattern, the houses being arranged along the roadside and the crossing being at the heart of the town and the main market place. In a nodal town, the roads radiate in all directions.

Transport and Communication Pattern:
Relief, population, size and resource development pattern of an area directly influence the means of transport and communication and their density. These are depicted through conventional signs and symbols. Means of transport and communication provide useful information about the area shown on the map.