Class 9 Social Science · Chapter 7

Samacheer Class 9 Social Science - Mapping Skills

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Chapter-wise textbook exercise answers for Mapping Skills with validation-aware solutions.

Answers marked verified were checked during generation against the chapter context and source question text.
Sections in this chapter
I. Choose the correct answer 3II. Match the following 1III. Consider the given statements 1IV. Answer in brief 6V. Give Reasons 3VI. Distinguish Between The Following 3VII. Answer in Paragraph 4VIII. MAP EXERCISE 1IX. HOTS 2
Your Progress - Chapter 70% complete
1I. Choose the correct answer3 questions
Q.1___________ indicates the purpose or theme of the map.v
  1. a. Title
  2. b. Scale
  3. c. Direction
  4. d. Legend
Solution

The title states the purpose or theme of the map (what the map is about).

Answer:

a

Q.2Standard symbols that are used in maps to convey a definite meaning are called ___________.v
  1. a. conventional signs and symbols
  2. b. coordinates
  3. c. grid references
  4. d. directions
Solution

Conventional signs and symbols are standardised map symbols used to represent features (e.g., roads, railways, churches) so map-readers understand them universally.

Answer:

a

Q.3GPS consists of a constellation of _____________ satellites.v
  1. a. 7
  2. b. 24
  3. c. 32
  4. d. 64
Solution

The NAVSTAR GPS system operates with a nominal constellation of 24 operational satellites spread in six orbital planes to provide global coverage.

Answer:

b

2II. Match the following1 questions
Q.IIMatch the following: 1. The art and science of mapping 2. Actual shape of the earth 3. NAVSTAR — (options: a) USA; b) Geoid; c) Cartography)v
  1. 1. The art and science of mapping
  2. 2. Actual shape of the earth
  3. 3. NAVSTAR
  4. a. USA
  5. b. Geoid
  6. c. Cartography
Solution

Correct matches (from the chapter text):
- 1 (The art and science of mapping) → Cartography. The book defines cartography as the art and science of map‑making.
- 2 (Actual shape of the earth) → Geoid. The chapter explains the earth's real form is a geoid (an oblate spheroid approximated by the geoid concept).
- 3 (NAVSTAR) → USA. NAVSTAR is the U.S. Global Positioning System (GPS) network.
Confidence: high — items and options are clearly supported by the mapping skills chapter text (pages shown in the raw input).

#Correct match
1c
2b
3a
3III. Consider the given statements1 questions
Q.III.1Assertion (A): The points at which the vertical and horizontal lines of the grid intersect are called coordinates. Reason (R): The lines that run horizontally and vertically are called Northings and Eastings respectively. Choose the right option: (a) Both (A) and (R) are true; (R) explains (A) (b) Both (A) and (R) are true; (R) does not explain (A) (c) (A) is correct; (R) is false (d) (A) is false; (R) is truev
  1. a. Both (A) and (R) are true; (R) explains (A)
  2. b. Both (A) and (R) are true; (R) does not explain (A)
  3. c. (A) is correct; (R) is false
  4. d. (A) is false; (R) is true
Solution

A is true: intersections of vertical and horizontal grid lines are specified by coordinates. R is true: horizontal grid lines are called northings and vertical grid lines eastings. But R does not explain why intersection points are called coordinates, so option (b) is correct.

Answer:

b

4IV. Answer in brief6 questions
Q.IV.1What is a map?v
Solution

Concise definition: maps present spatial information about places and features in a reduced form on a flat surface so that distances, directions and relationships can be understood and analysed.

Answer:

A map is a scaled, simplified two-dimensional representation of the Earth's surface (or part of it) showing selected natural and human-made features using symbols.

Q.IV.2What are the components of a map?v
Solution

Each component helps interpretation: title shows theme, scale shows reduction, legend explains symbols, north arrow shows orientation, grid gives exact location, and marginal info gives context and source.

Answer:

Main components: Title, Scale (RF/verbal/graphic), Legend (conventional signs and symbols), Direction indicator (north arrow), Grid/coordinates, Insets or locator map, Marginal information (projection, date, source).

Q.IV.3The distance between two cities A and B is 5 km. It is represented by a line of 5 cm on the map. Calculate the distance and give the answer in RF.v
Solution

5 km = 500,000 cm. Map distance = 5 cm. RF = map distance / ground distance = 5 cm : 500,000 cm = 1 : 100,000.

Answer:

RF = 1 : 100,000

Q.IV.4Mention a few surveying instruments.v
Solution

Common surveying instruments include: chain or measuring tape for distances; prismatic compass for bearings; plane table for field plotting; theodolite for measuring horizontal and vertical angles; leveling instrument (dumpy or auto-level) for differences in elevation; total station (electronic theodolite + EDM) for precise angles and distances; and GPS receivers for positioning.

Answer:

Chain/tape, prismatic compass, plane table, theodolite, leveling instrument (auto-level), total station, GPS.

Q.IV.5Define remote sensing.v
Solution

Remote sensing uses sensors (passive, e.g., optical, or active, e.g., radar) to detect electromagnetic energy from Earth's surface. The recorded data are processed and interpreted to map features, monitor changes and extract information for applications like land use, vegetation, and disaster assessment.

Answer:

Remote sensing is the technique of obtaining information about objects or areas from a distance, typically by recording reflected or emitted electromagnetic radiation from sensors mounted on aircraft or satellites, without direct contact.

Q.IV.6What are the components of remote sensing?v
Solution

Remote sensing involves an energy source (sun for passive or man-made for active), the path of radiation through the atmosphere, the target that reflects/emits energy, sensors that record the signal, platforms that carry sensors, transmission/storage of data, and subsequent processing, analysis and validation (ground truth) to produce usable information.

Answer:

Main components: (1) Energy source or illumination, (2) Radiation and atmosphere, (3) Target (object/area), (4) Sensor (detector), (5) Platform (satellite/aircraft), (6) Transmission, (7) Data processing and interpretation (including ground truth).

5V. Give Reasons3 questions
Q.V.1Satellite imageries stimulate map making.v
Solution

Because satellites supply detailed remote-sensing data quickly and repeatedly over large areas, they improve accuracy and timeliness of maps and support creation of thematic maps and GIS layers.

Answer:

Satellite imagery provides up-to-date, wide-area and accurate spatial data, helping cartographers detect land use, vegetation, water bodies and changes over time, thus stimulating map making.

Q.V.2Map is the basic tool of a geographer.v
Solution

Maps allow geographers to visualise location, extent, relationships, perform spatial analysis (e.g., distribution of resources, population), and support fieldwork, planning and GIS applications.

Answer:

Maps are the basic tool because they represent spatial relationships, distribution and patterns of physical and human phenomena, enabling analysis, comparison, planning and decision-making in geography.

Q.V.3Grid references are essential to find the exact location of places on a map.v
Solution

Because grids provide a standardized coordinate system, they allow users to communicate exact positions, measure distances/directions precisely, and locate features quickly on the map.

Answer:

Grid references give precise coordinates (eastings and northings or latitude/longitude) that locate any place on the map accurately, facilitating navigation, referencing and rescue operations.

6VI. Distinguish Between The Following3 questions
Q.VI.1Distinguish between: Globe and Mapv
Solution

Key differences — form (3D vs 2D), distortion (globes virtually none; maps may have projection distortions), scale/usability (globes show overall Earth; maps show detailed local information), portability (maps are easy to carry), and use (maps for navigation, planning; globe for overall Earth view).

Answer:

Globe: a three-dimensional scale model of Earth showing true shape and relative positions with no projection distortion. Map: a two-dimensional, scaled and often projected representation of all or part of Earth that may have distortions but is more portable and detailed for large-scale study.

Q.VI.2Distinguish between: Aerial photographs and satellite imageriesv
Solution

Differences include platform (aircraft vs satellite), coverage (small vs large), resolution (aerial generally higher spatial detail), cost and frequency (satellites provide frequent, wide coverage), and typical uses (aerial for detailed surveys; satellite for broad monitoring and thematic mapping).

Answer:

Aerial photographs: taken from aircraft at relatively low altitudes; high spatial resolution for small areas; often oblique or vertical; used for local mapping and detail. Satellite imageries: taken from space (satellites) covering large areas; varying spatial, spectral and temporal resolution; suitable for regional to global studies and repeated monitoring.

Q.VI.3Distinguish between: GIS and GPSv
Solution

Key differences — GPS provides positional data (latitude/longitude/elevation); GIS stores and analyses spatial data and uses positional inputs (e.g., from GPS) to create thematic maps, run queries and model spatial relationships.

Answer:

GPS (Global Positioning System) is a satellite-based system that provides precise location (coordinates) and time information to a receiver. GIS (Geographic Information System) is a computer system for storing, analysing, visualising and managing spatial and attribute data (layers) to make maps and perform spatial analysis.

7VII. Answer in Paragraph4 questions
Q.VII.1What do you mean by the term 'scale of the map'? Explain its classification.v
Solution

Define RF and give examples of expression forms. Explain that large-scale maps have larger representative fractions (smaller denominator) and show more detail, while small-scale maps have smaller detail and cover larger areas.

Answer:

Scale of a map is the ratio between a distance on the map and the corresponding distance on the ground. Classification: (1) Types of expression — Representative Fraction (RF) (e.g., 1:50,000), Verbal scale (e.g., '1 cm = 1 km'), and Graphic (linear) scale (a scale bar). (2) By extent/detail — Large-scale maps (show small area in more detail, e.g., 1:5,000–1:50,000), Medium-scale maps (e.g., 1:50,000–1:250,000), Small-scale maps (show large area with less detail, e.g., 1:250,000 and smaller like 1:1,000,000).

Q.VII.2Assertion (A) The legend of a map does not help us to understand the information in a map. Reason (R) It is usually placed at the left or right corner at the bottom of the map. Choose the right option: (a) (A) is false; (R) is true (b) Both (A) and (R) are true ; (R) does not explain (A) (c) (A) is correct; (R) is false (d) Both (A) and (R) are true ; (R) explainsv
  1. a. (A) is false; (R) is true
  2. b. Both (A) and (R) are true ; (R) does not explain (A)
  3. c. (A) is correct; (R) is false
  4. d. Both (A) and (R) are true ; (R) explains
Solution

A is false — the legend helps interpret symbols and understand the map. R is true — legends are usually placed in a corner (left/right bottom). Thus option (a) is correct.

Answer:

a

Q.VII.3Write a note on directions with relevant diagram.v
Solution

Explain usage: use compass or bearings to navigate; on maps always note the north arrow and projection; bearings give precise directional measurement; intercardinal points help give more specific directions. (Diagram: draw a circle with N at top, E at right, S bottom, W left and intermediate NE, SE, SW, NW.)

Answer:

Directions: Cardinal directions are North (N), South (S), East (E) and West (W). Intercardinal (ordinal) directions are NE, SE, SW, NW. Bearings measure direction as degrees clockwise from North (0° or 360°) — e.g., East = 90°. On maps a north arrow shows orientation; remember magnetic north differs slightly from true (geographic) north and maps usually indicate which is used.

Q.VII.4Explain the major uses of GPS. Explain any one in detail.v
Solution

List the principal application areas of GPS. For navigation, GPS satellites transmit precise time and orbital data; a receiver measures signal travel times from multiple satellites, computes distances and uses trilateration to determine its 3D position and velocity. This enables route guidance, location services and safe navigation in road, sea and air transport.

Answer:

Major uses: navigation (road, maritime, aviation), mapping and surveying, land and resource management, vehicle and asset tracking, disaster management and emergency response, precision agriculture, scientific research (geodesy, tectonics), and timing synchronization. Detailed—Navigation: GPS provides real‑time position, speed and time by trilateration from satellites; a receiver calculates latitude, longitude and altitude and can give turn‑by‑turn directions, estimated arrival times, and track routes for vehicles, ships and aircraft.

8VIII. MAP EXERCISE1 questions
Q.VIII.1With the help of an atlas, mark the following on the outline map of Tamil Nadu. a) The latitude and longitude of Chennai. b) Mark the city located at 10° N, 78° E. c) Locate the city approximately on 11° N and 76° E. d) Find the latitude and longitude of Kanniyakumari and mark it.v
Solution

Provide these commonly used approximate coordinates for marking on the outline map: (a) Chennai — approximately 13°05′N, 80°16′E. (b) City at 10°N, 78°E — close to Madurai (Madurai is ≈ 9°56′N, 78°07′E), so mark Madurai near 10°N,78°E. (c) Approximately 11°N,76°E — near the Nilgiris/Ooty region (Udhagamandalam/Ooty ≈ 11°24′N, 76°41′E); mark the highland town in the western part. (d) Kanniyakumari — approximately 8°04′N, 77°32′E. Use your atlas to place precise points and then transfer them to the outline map using the latitude/longitude grid.

Answer:

See instructions and approximate coordinates below.

9IX. HOTS2 questions
Q.IX.1Can you imagine a world without satellites?v
Solution

Brief explanation: satellites provide positioning (GPS), communication, TV, internet backbone links, meteorological data, Earth observation for maps and agriculture, and defence/intelligence. Without them, transportation, forecasting, global commerce, emergency response and scientific data collection would be greatly impaired.

Answer:

A world without satellites would lack GPS navigation, reliable weather forecasting, satellite TV and global communications, many scientific observations and satellite-based remote sensing for mapping, disaster management and environmental monitoring; global connectivity and many modern services would be severely disrupted.

Q.IX.2Imagine you are a cartographer. Draw the map of your area.v
Solution

Guidance for students: include clear title, scale (RF or scale bar), north arrow, legend, labels for important features (roads, rivers, settlements), and neat, proportionate drawing. Use grid or graph paper for accuracy.

Answer:

Steps to draw a map: 1) Survey the area and collect data (field measurements, GPS points, photos). 2) Decide map purpose and scale. 3) Choose projection and prepare base layout. 4) Plot features to scale using measured distances and coordinates. 5) Use conventional symbols; prepare legend. 6) Add title, north arrow, scale bar and marginal information. 7) Finalise neatness, accuracy and labeling.