Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Social Science Guide Pdf Geography Chapter 7 Mapping Skills Text Book Back Questions and Answers, Important Questions, Notes.

Tamilnadu Samacheer Kalvi 9th Social Science Solutions Geography Chapter 7 Mapping Skills

Samacheer Kalvi 9th Social Science Mapping Skills Text Book Back Questions and Answers

I. Choose the best answer

Question 1.
The new phase in topographical surveying in the 20’h century is __________
(a) toposheets
(b) aerial photography
(c) maps
(d) satellite imagery
Answer:
(d) satellite imagery

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 2.
indicates the purpose or theme of the map.
(a) Title
(b) Scale
(c) Direction
(d) Legend
Answer:
(a) Title

Question 3.
Standard symbols that are used in maps to convey a definite meaning are called __________
(a) conventional signs and symbols
(b) coordinates
(c) grid references
(d) directions
Answer:
(a) conventional signs and symbols

Question 4.
Which one of the following maps show us a very large area with less details?
(a) Large scale
(b) Thematic
(c) Physical
(d) Small scale
Answer:
(d) Small scale

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 5.
GPS consists of a constellation of satellites.
(a) 7
(b) 24
(c) 32
(d) 64
Answer:
b) 24

II. Match the following

  1. The art and science of mapping – (a) USA
  2. Thematic mapping – (b) Geoid
  3. Actual shape of the earth – (c) Inmarsat
  4. A satellite – (d) Political map
  5. NAVSTAR – (e) Cartography

Answer:

  1. – (e)
  2. – (d)
  3. – (b)
  4. – (c)
  5. – (a)

III. Consider the given statements and choose the right option given below

Question 1.
Assertion (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.
(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 true
Answer:
(a) Both (A) and (R) are true ; (R) explains (A)

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 2.
Assertion (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.
(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) explains (A)
Answer:
(a) (A) is false ; (R) is true

IV. Answer in Brief

Question 1.
Name the different methods to represent the Earth.
Answer:

  1. A map is the basic tool of a geographer. It illustrates the earth’s surface clearly and effectively through a combination of drawings, words and symbols.
  2. A map projection is a way of, showing the spherical shaped earth on a flat piece of paper.
  3. A map projection is a systematic transformation of the latitudes and longitudes of location from the surface of a sphere or an ellipsoid into locations on a plane.
  4. A Globe is a spherical model of earth. Globe Serve similar purposes to maps but unlike maps do not disturb the surface that they portray except to scale it down. A globe of earth is called terrestrial globe.

Question 2.
What is a map?
Answer:

  1. A map is the basic tool of a geographer.
  2. It illustrates the earth’s surface clearly and effectively through a combination of drawings, words and symbols.
  3. Thus, maps form an integral part of teaching geography.
  4. A map is a location guide.

Question 3.
What are the three components of a map?
Answer:
A map should include the following components namely, the title, scale, direction, grid reference, projection, legend, conventional signs and symbols.

Question 4.
The 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.
Answer:
Representative Fraction (R.F.) = \(\frac { Distance on the map }{ Distance on the ground }\) = \(\frac { 5 Cm }{ 5 km }\) = 1:1,00,000

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 5.
Mention a few surveying instruments.
Answer:
Geographers mainly use Chain, Prismatic compass, Plane table, Dumpy level, Abney level, Clinometre, Theodolite, Total Station and GNSS to measure the distance, angle, altitude and position of the area of survey.

Question 6.
Define remote sensing.
Answer:

  1. Remote Sensing refers to the observation and measurement of earthly objects without touching them.
  2. ‘Remote’ means far away and ‘Sensing’ means observing or collecting information.

Question 7.
What are the components of remote sensing?
Answer:
Components of remote sensing are

  1. Energy source
  2. Transmission path
  3. Target
  4. Sensor

V. Give Reasons

Question 1.
Satellite imageries stimulate map making.
Answer:

  1. Cartographic object extraction from digital imagery is a fundamental operations for GIS update.
  2. Remote sensing is a multidisciplinary technique of electronic and analog image acquisition and exploitation which includes aerial photography.
  3. The images thus acquired by remote sensing are further processed to extract the different features.

Question 2.
Map is the basic tool of a geographer.
Answer:

  1. It illustrates the earth’s surface clearly and effectively through a combination of drawings, words and symbols.
  2. Thus, maps form an integral part of teaching geography. A map is a location guide.

Question 3.
Grid references are essential to find the exact location of places on a map.
Answer:

  1. The location of a place can be simply defined by its latitude and longitude.
  2. The points at which the vertical and horizontal lines of the grid intersect are called coordinates.
  3. Therefore grid references are essential to find the exact location of a place.

VI. Distinguish between the following

Question 1.
Globe and Map.
Answer:
Map:

  1. Gives a two dimensional presentation of a region.
  2. It is easy to use and portable.
  3. The region can be easily identified.
  4. It presents a distributed view as it is flat.

Globe:

  1. Gives a three dimensional presentation of the entire world.
  2. It is not that easy to carry.
  3. It is called a duplicate earth.
  4. It is more accurate.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 2.
Large scale map and small scale map.
Answer:
Large Scale Map

  1. It shows only small area.
  2. But it shows in great detail.

Small Scale Map

  1. It shows a large area.
  2. But it shows in less detail.

Question 3.
Aerial photographs and Satellite imageries
Aerial photographs:

  1. Surveying can be planned and executed in a shorter time economically.
  2. It covers a small area and needs permission from authorities.

Satellite imageries:

  1. High cost of satellite systems. Takes at least 10 years to plan, construct test and launch.
  2. It allows a global coverage and does not require permission.

Question 4.
GIS and GPS
Answer:
GIS:

  1. The Geographic Information System is a computer program that process data linked to certain places or locations.
  2. GIS finds its strongest use in resources management, telecommunications and urban and regional planning.

GPS:

  1. The Global Position System is a network that locates certain places here on earth.
  2. Weather forecasting, earthquake monitoring and environmental protection can be done effectively by using GPS.

VII. Answer in paragraph

Question 1.
What do you mean by the term ‘scale of the map’? Explain its classification.
Answer:

  1. Scale is one of the components of map.
  2. Scale makes it possible to reduce the size of the whole earth to show it on a piece of paper.
  3. A scale is a ratio between the actual distance on the map to the actual distance on the ground.
  4. Scales can be represented in three methods.
  5. They are :

(a) Statement
(b) Representative Fraction (R.F)
(c) Linear or Graphical scale methods.

(a) Statement Scale:

  1. The statement scale describes the relationship of map distance to ground distance in words, such as one centimetre to ten kilometres. It is expressed as 1cm = 10 km.

(b) The Representative Fraction (R.F):

  1. It describes the proportion or ratio of the map distance to ground distance. It is usually abbreviated as R.F. It is stated as 1/100000 or 1:100000
  2. This means that one unit on the map represents 100,000 of the same unit on the ground.
  3. This unit may be an inch or a centimetre or any other linear measurement unit.
    Representative Fraction (R.F.) = \(\frac { Distance on the map }{ Distance on the Ground }\)

(c) Linear (or) Graphical scale: In geography, a linear scale is represented by a straight line divided into equal parts (Primary and secondary) to show what these markings represent on the actual ground. This scale helps in the direct measurement of distance on the map.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 2.
Write a note on directions with a relevant diagram.
Answer:
Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

  1. Maps are drawn normally with north orientation.
  2. North direction in a map is always towards the North Pole of the earth.
  3. If you position yourself looking at the North Pole, on your right will be the east; your left will be the west; at your back will be south.
  4. These four main directions are called the cardinal directions.
  5. Direction is usually indicated on a map by a North-South line, with the North direction represented by an arrow head.

Question 3.
Explain the major uses of GPS? Explain about any one.
Answer:
GPS has made a considerable impact on almost all positioning, navigation, timing and monitoring applications. It provides particularly coded satellite signals that can be processed in a GPS receiver, allowing the receiver to estimate position, velocity and time.

  1. The (GPS) Global Positioning System is a U.S. owned utility that provides users with positioning, control segment and the user segment.
  2. The GPS ground segment (also referred to as control segment or operational control system) is responsible for the proper operation of the GPS system.
  3. The GPS control segment is composed by network of monitor stations (MS), a Master Control Systems (MCS) a backup of the MCS and Ground Antenna (GA).
  4. The GPS space segment consists of a constellation of transmitting radio signal to users. The linked states is committed to maintaining the availability of atleast 24 operational GPS satellites, 95% of the times.
  5. The user segment is the practice of dividing all customers into segments based on characteristics they share. For example sorting users by region, language, or behaviour.

Question 4.
Bhuvan has tremendous uses for scientists, policy makers and the general public. Justify
Answer:

  1. Bhuvan (Sanskrit for Earth) is a free internet based computer application launched by the Indian Space Research Organization (ISRO) on August 12th 2009.
  2. It enables visualization of Indian Remote Sensing (IRS) images taken over a year ago, by ISRO’s seven satellites, including CartoSat-1 and CartoSat-2.
  3. Using Bhuvan connected to Internet, one can explore places of interest, scenes of events in the news or parts around the world they may never visit in person, by either entering the names of places or co-ordinates (latitudes and longitudes).
  4. Bhuvan has tremendous uses for scientists, academicians, policy makers or the general public.

VIII. Map Exercise

Question 1.
With 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 Kanyakumari and mark it.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

IX. HOTS

Question 1.
Can you imagine a world without satellites?
Answer:

  1. Today a growing number of satellites orbit around the Earth, making various earth observation, communication, navigation and science application possible.
  2. While we may not always realize or acknowledge their existence, the important role these systems play in our daily lives cannot be under estimated.
  3. As technology advances, the potential of satellites will undoubtedly continue to grow. New markets will merge along with now opportunities to push the boundaries of what space technology currently offers.
  4. Likely satellites reach just about everywhere today. In certain isolated parts of our planet. Satellites provide inhabitants with access to telephone service, 4G / 5G, broadband and work.
  5. GPS help us to travel from A to B without getting lost along the way.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 2.
Imagine you are a cartographer. Draw the map of your area.
Hints:

  1. Cartographers spend most of their times to collect and verily data used in creating maps.
  2. A Cartographer will also collect and analyze geographical data, such as population density, demographic characteristics and animal precipitation pattern.
  3. As a cartographer I will be involved with the scientific, technological and artistic aspects of developing and producing maps.
  4. It will present complex information as diagrams, charts and spreadsheets as well as in the form of conventional maps.
  5. Map of the area is to be drawn by the student.

Intext Activity

Question 1.
Imagine you are standing in India facing north, find in which direction are the following located using the map given below
Answer:

  1. Saudi Arabia West
  2. Myanmar East
  3. China North
  4. Indian ocean South
  5. Kazakhstan North
  6. Sumatra South East
  7. Afghanistan West

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Samacheer Kalvi 9th Social Science Mapping Skills Additional Important Questions and Answers

I. Choose the best answer

Question 1.
The foundation for map making in India war laid during the period ______
(a) Aryan
(b) Vedic
(c) Gupta
(d) Chola
Answer:
(b) Vedic

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 2.
International boundaries are marked in ______ colour codes.
(a) Brown
(b) Blue
(c) Red
(d) Pink
Answer:
(d) Pink

Question 3.
A synoptic chart means
(a) Weather map
(b) Travelogue
(c) Thematic map
(d) General maps
Answer:
(a) Weather map

Question 4.
Aerial photographs were taken by Felix Nadar in __________
(a) 1850
(b) 1852
(c) 1858
(d) 1860
Answer:
(c) 1858

Question 5.
GPS technology has tremendous applications in __________
(a) Mobile phones
(b) Watches
(c) ATMs
(d) All the these
Answer:
(d) All the these

II. Consider the given statements and choose the right option given below.

Question 1.
Assertion (A): GNSS promotes the safety and convenience of transport.
Reason (R): GNSS applications are used in tracking or mapping vehicles, ships and aircraft.
(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 true
Answer:
(a) Both (A) and (R) are true; (R) explains (A)

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 2.
Statement (I): Surveying is done to measure the angle, direction, area, height and distance of an object.
Statement (II): A topographical map is the technique of meteorologists to display all the weather data.
(a) Statement (I) is true; (II) is false
(b) Statement (II) is true; (I) is false
(c) Statement (I) and (II) correct
(d) Statement (I) and (II) Wrong
Answer:
(a) Statement (I) is true; (II) is false

III. Match the following

  1. Azimuthal – (a) Water towers
  2. Light Blue – (b) Rope – stretchers
  3. Travelogue – (c) Journalist
  4. Egypt – (d) Polar projection
  5. Felix Nadar – (e) Tourist map

Answer:

  1. – (d)
  2. – (a)
  3. – (e)
  4. – (b)
  5. – (c)

IV. Answer in Brief.

Question 1.
Mention about the first map maker.
Answer:
Anaximander was the first ancient Greek to draw a map of the known world. It is for this reason that he is’considered by many to be the first map maker (the first cartographer).

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 2.
Who is a cartographer?
Answer:
A cartographer is one who measures, analyzes and interpret geographical information to create ‘ maps and charts for political, cultural and educational purposes.

Question 3.
Mention the three types of map symbols.
Answer:

  1. Point Symbols – Buildings, dipping tanks, trigonometrical beacons
  2. Line Symbols – Railways, roads, power lines, telephone lines
  3. Area Symbols – Cultivated lands, ponds, orchards and vineyards

Question 4.
What is a travelogue?
Answer:
A travelogue includes all the information required by a tourist like communication, transportation, hotels, tourist spots, health centres, ATM, petrol stations etc.

Question 5.
Remote sensing can be either passive or active – Explain.
Answer:

  1. Remote sensing can be either passive or active.
  2. Active systems emit their own source of light energy such as RADAR.
  3. Passive systems depend on sunlight as energy source.

Question 6.
Mention the disadvantages of Remote sensing.
Answer:

  1. It is difficult to prepare large scale maps from obtained satellite data.
  2. The technique is very expensive for small areas requiring one time analysis.

Question 7.
Mention the advantages of GIS.
Answer:
The advantages of GIS are

  1. Maps produced by GIS analysis can be used to pinpoint problem areas.
  2. GIS finds its strongest use in resources management, telecommunications and urban and regional planning.
  3. GIS helps in planning the land-use requirements. The local government uses GIS for taxation and planning.

Question 8.
Write about the hardware and software functions of a GIS.
Answer:
The hardware and software functions of a GIS are,

  1. Data input and verification
  2. Compilation
  3. Storage
  4. Updating and changing
  5. Management and exchange
  6. Manipulation
  7. Retrieval and presentation
  8. Analysis and combination

Question 9.
What is meant by cyber cartography?
Answer:
Cyber cartography is a term that is used to define all the aspects of current state of Web andvirtual mapping.

Question 10.
What are geo objects?
Answer:

  1. Geographical objects in the real world are matched to program objects known as geo objects.
  2. Geo objects include placemarks, circles, polylines, rectangles, polygons and their collections.
  3. Place markers indicate a place on a map.

Question 11.
What are the advantages of Bhuvan?
Answer:

  1. Bhuvan, due to 3D rendering, gives the impression of moving through real space through the entire globe.
  2. Students can use Bhuvan to understand subjects ranging from Sciences to History of places.
  3. It provides information on natural resources and timely information on disasters.
  4. Administrators use it for monitoring various developmental schemes.

V. Give Reasons

Question 1.
Conventional signs and symbols are standard symbols used on a map.
Answer:

  1. A map is a global language and it needs to be drawn according to the international standards
  2. Conventional signs and symbols are standard symbols used on a map and explained in the legend to convey a definite meaning.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 2.
Surveys help to prepare physical maps.
Answer:

  1. Surveying is done to measure the angle, direction, area, height and distance of an object or place on the surface of the earth using instruments.
  2. Surveying techniques are used to obtain the field data and to prepare maps.
  3. Hence knowledge of surveying helps to prepare physical maps.

VI. Answer in paragraph

Question 1.
Write a note on Grid reference.
Answer:

  1. The location of a place can be simply defined by its latitude and longitude.
  2. In normal practice, latitude is stated first and then comes the longitude.
  3. The latitude and longitude of a place can be expressed in units of degree, minutes and seconds.
  4. A grid is a set of lines with alphanumeric codes for defining a location on a map in many topographical sheets.
  5. The lines that run horizontally from left to right of the map are known as northings.
  6. The lines that run vertically from the top to the bottom of the map are called eastings.
  7. The points at which the vertical and horizontal lines of the grid intersect are called coordinates which are identified by numbers or letters.

Question 2.
What are the colour codes used with map symbols.
Answer:

  1. Brown: land or earth features – contour lines, eroded areas, prominent rock outcrops, sand areas and dunes, secondary or gravel roads
  2. Light Blue: water features – canals, coastlines, dams, lakes, marshes, swamps and levees, ponds, rivers and water towers.
  3. Dark Blue: national waterways
  4. Green: vegetation features – cultivated fields, golf courses, nature and game reserve boundaries, orchards and vineyards, recreation grounds, woodland
  5. Black: construction features – roads, tracks, railways, buildings, bridges, cemeteries, communication towers, dam walls, excavations and mine dumps, telelphone lines, power lines, windpumps, boundaries
  6. Red: construction features – national, arterial and main roads, lighthouses and marine lights
  7. Pink: international boundaries

Question 3.
Explain the types of maps.
Answer:
(a) On the basis of scale, maps can be classified into:

  1. Large scale maps: Large amount of detail; can only show a small area.
  2. Small scale map: Small amount of detail; can show a large area,

(b) On the basis of utility and purpose, they are classified as:

  1. General maps / Topographic Maps (physical and political maps)
  2. Thematic map (spatial variations of single phenomena)
  3. Special purpose maps (Braille maps for blind people, maps for neo literates, military maps, navigational charts, etc).

Question 4.
Write a short note on
(a) Topographical Maps and
(b) Weather Maps
Answer:
(a) Topographical Maps

  1. Topographical maps show main features like landforms, water features, forests, settlements, agricultural fields, other land use, transportation and communication networks.
  2. These maps are general purpose maps and are drawn at quite large scales.
  3. The Survey of India prepares the topographical maps in India for the entire country.

(b) Weather Maps

  1. A weather map is the technique of meteorologists to display all the weather data recorded at various stations of a country at a particular point of time into a compact outline map using symbols and isolines.
  2. A weather map, otherwise called a synoptic chart, helps in weather analysis and weather forecast of the country/region for the next two to three days.

Question 5.
Explain the process of remote sensing.
Answer:
Remote Sensing

  1. The EMR (Electro Magnetic Radiation) or solar radiation is the primary source of energy for remote sensing.
  2. Sunlight travels from the sun through the atmosphere, before it reaches the earth surface. In the atmosphere, the sun’s rays are not obstructed by any object.
  3. When solar radiation falls on the earth’s surface, some of its energy is absorbed. While some is transmitted through the surface, the rest is reflected. Surfaces naturally emit radiation in the form of heat.
  4. Sensors in the satellite record the reflected and emitted radiation. Each surface/object possesses a characteristic spectral signature, a unique pattern of reflecting sunlight.
  5. The energy recorded by the sensor has to be transmitted to a ground station where the data are processed into an image.
  6. The processed image is interpreted either visually by human interpreters or by computer aided techniques called digital image processing to identify and distinguish between the different spectral signatures to get information about objects/places.
  7. Finally, we understand and apply the extracted information in mapping the area or assist in solving the particular problem.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 6.
What are the advantages and disadvantages of Remote Sensing?
Answer:
(a) Advantages of Remote sensing:

  1. It is the only practical way to obtain data from inaccessible regions, e.g. Antarctica, Amazon forest.
  2. It helps in constructing cheap base maps in the absence of detailed land surveys.
  3. It detects the spread of natural calamities such as flood, forest fire and volcanic eruption, so that immediate rescue operations and planning can be carried out.

(b) Disadvantages of Remote sensing:

  1. It is difficult to prepare large scale maps from obtained satellite data.
  2. The technique is very expensive for small areas requiring one time analysis.

Question 7.
How is remote sensing useful in disaster management?
Answer:

  1. Remote sensing technology is highly used in disaster management to study the effects of earthquakes, tsunamis, cyclones, volcanic eruption, floods and wildfires.
  2. The preliminary data is retrieved from satellites like LANDSAT, CARTOSAT, OCEANSAT, etc.
  3. Fire and flood details can be extracted and delivered to relevant authorities within two hours of satellite image capture.
  4. E.g. major earthquakes in China and New Zealand, bushfire in Victoria and floods in Kerala.
  5. Dynamic phenomena such as flood, movement of wild animals, shoreline changes, finding lost ships and planes.
  6. Researchers use satellite imageries for these.

Question 8.
Explain the Global Navigation Satellite System (GNSS).
Answer:

  1. In the 21st century, GNSS has become a part of our lives to promote the safety and convenience of transport.
  2. Global Navigation Satellite System (GNSS) is a satellite system connected with a small electronic receiver or tracker to locate, monitor and track a user’s vehicle wherever in the world.
  3. It can also set up instant alerts when a driver of a vehicle speeds or deviates from a particular area.
  4. GNSS applications are used in tracking or mapping vehicles, ships and aircraft.
  5. group of satellites (Space Segment) working with a network of ground stations (Control Segment) provide location data
  6. The receiver (User Segment) converts satellite signals into location, speed and time data
  7. Examples of GNSS:
    • Europe’s Galileo
    • USA’s NAVSTAR Global Positioning System (GPS)
    • Russia’s Global’naya Navigatsionnaya Sputnikovaya Sistema (GLONASS)
    • China’s BeiDou Navigation Satellite System
    • India’s NAVIC satellite system

Question 9.
Explain the Geographical Information System (GIS).
Answer:

  1. Geographic Information System is a computer-based tool for managing a large amount of data collected for a given geographic region through remote sensing, GPS and other sources.
  2. The Geographic Information’System is a combination of computer hardware, software, geographic data and the personnel.
  3. G – Geographic – A particular area; I – Information – facts in order; S – System – arrangement
  4. GIS was first recognised in the late 1950s by Waldo Tobler and Roger Tomlinson (Canada).
  5. Prime examples of importing GIS for public welfare are Google Maps, Yahoo Maps and Google Earth.
  6. The key ingredient is location. We must have a coordinate, an address or a distance from a known point that helps us to link the information to a location on a map.
  7. Each type of data of an area is stored as a separate ‘layer’ of the map.
  8. In GIS, layers may be used some times and removed according to need.
  9. Examples are hospitals, schools, water bodies, parks and ATMs.
  10. The computers can create maps showing any combination of data.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 10.
Write a note on Google Earth.
Answer:

  1. Google Earth is a web based computer application.
  2. Google Earth is a virtual globe that renders a 3D representation of the Earth.
  3. It combines the power of Google Search with maps, satellite imageries, aerial photographs, GIS data and 3D buildings to visualize the world.
  4. Google Earth allows users to see cities and buildings looking perpendicularly down or at a tilted angle.
  5. Google Earth allows users to search for addresses of some countries, enter coordinates or simply use the mouse to browse a location.
  6. Google Earth also has Digital Elevation Model (DEM) data for many major cities.
  7. This means one can view Mount Everest or buildings in three dimensions, instead of 2D.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 7 Mapping Skills

Question 11.
Distinguish between Airborne remote sensing and spaceborne remote sensing.
Answer:
Airborne remote sensing:

  1. In airborne remote sensing, downward or sideward looking sensors are mounted on an aircraft to obtain images of the earths surface.
  2. An advantages of airborne remote sensing is the capability of offering very high spatial resolution images (20 cm or less)

Spaceborne remote sensing:

  1. In spaceborne remote sensing, sensors are mounted on board a spacecraft (space shuttle or satellite) orbiting the earth.
  2. At present their one several remote sensing satellites proving imagery for research and operational applications.

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