Mapping Skills

Class 9 | Social Science — Geography | Unit 7

Class 9 Unit 7 Geography

UNIT 7 Mapping Skills

Learning objectives

To introduce maps

To read maps using its components

To learn the methods of surveying and other techniques of acquiring map data like aerial photography and satellite remote sensing

To gain knowledge of the latest techniques of mapping, namely GIS and GNSS

Introduction

With maps on hand, one can see the world in one sweep. A map is worth a thousand words. Mapping skills are the basics to understand a map and to interpret the area depicted. Maps are introduced with its components such as scale, signs and symbols. Surveying is the process of recording the measurement of a land area. Its outcomes are the data sources of maps. This lesson deals with the latest techniques of mapping - remote sensing, GPS, GIS, global navigation system and web maps of the twenty first century.

7.1 Map as a Tool

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. Thus, maps form an integral part of teaching geography. A map is a location guide.

Do You Know?

A cartographer is one who measures, analyzes and interprets geographical information to create maps and charts for political, cultural and educational purposes.

7.1.1 Maps and Cartography

Maps are drawings of an area as seen from above. A map is defined as the miniature image of the 3 dimensional earth's surface on a paper/cloth or any flat surface. Maps can show a whole or part of the world. Maps are drawn to a scale and direction. Maps have legends to explain the meaning of symbols and colours used on it. The art of map - making is called Cartography.

7.1.2 Components of a map

A map should include the following components namely, the title, scale, direction, grid system, projection, legend, conventional signs and symbols.

(A) Title

It indicates the purpose or theme of the map. Example: India – Physical, World – Political, Tamil Nadu – Transport.

(B) Scale

Scale makes it possible to reduce the size of the whole earth to show it on a piece of paper. A scale is a ratio between the actual distance on the map to the actual distance on the ground. Scales can be represented in three methods. They are the Statement, Representative Fraction (R.F) and Linear or Graphical scale methods.

Statement scale

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.

The Representative Fraction (R.F)

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. This means that one unit on the map represents 100,000 of the same unit on the ground. This unit may be an inch or a centimetre or any other linear measurement unit.

Thus, Representative Fraction (R.F.) = Distance on the map / Distance on the ground

For example: To find the RF when the scale is 1 cm to 1km.

Here, 1 cm =1 km

According to the formula, R.F= 1 cm by 1 k m

Convert the km to cm. Therefore, 1km =100000 cm.

So, RF. is 1:100000.

Exercise A. Practice Problem

1. Find the R.F. when the scale is 1 centimetre to 2 kilometre.

Linear (or) Graphical scale

In a map, 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.

(C) Direction

Maps are drawn normally with north orientation. North direction in a map is always towards the North Pole of the earth. 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. These four main directions are called the cardinal directions. Direction is usually indicated on a map by a North-South line, with the North direction represented by an arrow head.

Activity B. Direction Exercise

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

Saudi Arabia

Myanmar

China

Indian Ocean

Kazakhstan

Sumatra

Afghanistan

Mnemonic device or memory technique to recall cardinal directions is the sentence "Never Eat Soggy Wheaties." (North, East, South and West)

(D) Grid System

The location of a place can be simply defined by its latitude and longitude. In normal practice, latitude is stated first and then comes the longitude. The latitude and longitude of a place can be expressed in units of degree, minutes and seconds.

Do You Know?

The mainland of India extends from 8 degree 4 minutes North to 37 degree 6 minutes North latitude and from 68 degree 7 minutes East to 97 degree 25 minutes East longitude. Here, o is degree (')is minutes.

Activity C. Grid Exercise

Use grids to enlarge Australia.

(E) Projection

A map projection is a way of showing the spherical shaped earth on a flat piece of paper. Where does the word 'projection' come from? Imagine a clear globe with latitude and longitude lines and the outlines of the landmasses on it. Suppose there was a light bulb inside the globe. If you wrapped a piece of paper around the globe and turned on the light bulb, the outlines of the grid and landmasses would be projected onto the paper. Map projection is defined as the transformation of spherical network of latitudes and longitudes on a plane surface. Projections are drawn to maintain the shape, area and directions. The three methods in widest use are as follows:

• Projection on the surface of a cylinder
• Projection on to the surface of a cone
• Projection directly onto a flat plane, called planar or zenithal or azimuthal projection

(F) Legend

The legend of a map helps to understand the map details which are placed at the left or right corner at the bottom of the map.

(G) Conventional signs and symbols

Conventional signs and symbols are standard symbols used on a map and explained in the legend to convey a definite meaning. The topographic map contains a variety of information about physical and cultural features These are shown by using signs and symbols in various colours so that the clarity of the map is maintained. There are three types of map symbols:

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

Do You Know?

The actual shape of the Earth is termed Geoid, which is an oblate spheroid. The "azimuthal" polar projection is depicted on the United Nations flag. North America was prominent on the initial 1945 UN flag (which had the longitude line 90 degrees west pointing upwards). The following year, the map on the flag was reoriented to be more neutral by having the International Date Line (180 degrees east, lying in the middle of the Pacific Ocean) pointing upwards. The map ends at 60 degrees South latitude, meaning Antarctica does not appear.

Colour codes used with map symbols:

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, telephone lines, power lines, windpumps, boundaries

6. Red: construction features - national, arterial and main roads, lighthouses and marine lights

7. Pink: international boundaries

7.1.3. Survey

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. Surveying techniques are used to obtain the field data and to prepare maps. A knowledge of surveying helps one in map-making, particularly in the preparation of physical maps. 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.

Early History of Surveying: In Egypt, surveyors were called 'rope stretchers' because they used ropes to measure distances. The Egyptian 'Rope Stretchers'

7.2 Remote Sensing as a Source of Map Data

Remote Sensing refers to the observation and measurement of earthly objects without touching them. 'Remote' means far away and 'Sensing' means observing or collecting information. Remote sensing means acquiring information of things/places from a distance, using a variety of tools and methods.

Do You Know?

We operate three remote sensing organs in our body.

a) Eyes -sense of sight

b) Nose - sense of smell

c) Ear – Sense of hearing

Remote sensing has a long history, dating back from the use of cameras carried by balloons and pigeons in the 18th and 19th centuries. During the 20th century, airborne photographs and satellite remote sensing developed swiftly

7.2.1. Aerial photography

Aerial photography refers to the technique of obtaining information about places or objects or phenomena with the help of photographs taken using cameras mounted on low flying birds, balloons, helicopters, aeroplanes and drones. The aerial photographs are captured continuously with a time gap of 10-30 seconds at a fixed height. Each photo will have a slight overlap of the area in the preceding photo. By making a mosaic of all the photos excluding the overlapping areas, a stereoscopic (3D) image of the study area can be produced.

Do You Know?

Felix Nadar was a French photographer, journalist, novelist and balloonist. In 1858, he became the first person to take aerial photographs. He took his first photograph in 1853 and pioneered the use of artificial lighting in photography, working in the catacombs of Paris. Around 1863, Nadar built a huge (6000 m³) balloon named Le Géant ('The Giant').

7.2.2 Satellite Remote Sensing

Satellite remote sensing is the science of collecting data about an object or area from artificial satellites orbiting the Earth. The term 'satellite imagery' refers to digitally transmitted images of the satellites.

7.2.3 Global Navigation Satellite System (GNSS)

Have you ever booked a cab using a smart phone app? Did you see the map showing the route of your travel and movement of your vehicle on mobile phones? How is it possible to calculate the time duration of your travel?

Comparison: Satellite remote sensing vs Aerial Photography

Satellite remote sensing:

• High cost of satellite systems. Takes at least 10 years to plan, construct, test and launch.
• Satellites collect large amount of data of the entire area in a short span. It allows global coverage and does not require permission.
• Satellites circle the Earth; they can repeat and revisit easily.
• Weather does not affect the functioning of satellites.
• All information is digital; it can be easily integrated with software for image improvement

Aerial Photography:

• Surveying can be planned and executed in a shorter time economically.
• Takes more time to capture an area. Aircraft needs to fly back and forth.
• It covers a small area and needs permission from authorities.
• Revisits or repeatability involves extra cost.
• Adversely affected by bad weather
• It is an analogue record, so no further improvement is possible after obtaining photographs.

In the 21st century, GNSS has become a part of our lives to promote the safety and convenience of transport. 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. It can also set up instant alerts when a driver of a vehicle speeds or deviates from a particular area. GNSS applications are used in tracking or mapping vehicles, ships and aircraft. A group of satellites (Space Segment) working with a network of ground stations (Control Segment) provide location data. The receiver (User Segment) converts satellite signals into location, speed and time data.

Examples of GNSS

Europe-Galileo

USA-NAVSTAR Global Positioning System (GPS)

Russia-Global'naya Navigatsionnaya Sputnikovaya Sistema (GLONASS)

China- BeiDou Navigation Satellite System

India's - IRNSS (NAVIC) system

a. Global Positioning System (GPS)

Without the Global Positioning System (GPS) on our vehicles and mobile phones, we would feel lost. GPS is the United State. implementation of the world's first and currently the most used Global Navigation Satellite System (GNSS) created by the United State. Department of Defense (DOD). It became fully operational in 1995. NAVSTAR (Navigation Satellite Timing and Ranging) is a network of 24 United State. satellites in six different orbits in space flying 20,350 km above the surface of the Earth; each one circles the planet twice a day to provide continuous, worldwide coverage. GPS receivers now come in all shapes and sizes, Most are the size of a cellular phone. Some are handheld, others are installed in ships, planes, trucks and cars.

Advantages of GPS

GPS technology has tremendous applications in everything from mobile phones, watches, bulldozers, shipping containers and ATMs

The main purpose of GPS is to help in providing accurate transport data (distance, route and direction).

It helps in military searches and rescue in wars.

It can work as a reliable tourist guide.

GPS helps during accident and rescue efforts, speeding the delivery of emergency services and disaster relief.

Weather forecasting, earthquake monitoring and environmental protection can be done effectively by using GPS.

b. Geographic Information System (GIS)

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. The Geographic Information System is a combination of computer hardware, software, geographic data and the personnel.

G - Geographic - A particular area

I - Information - facts in order

S - System - arrangement

GIS was first recognised in the late 1950s by Waldo Tobler and Roger Tomlinson (Canada). Prime examples of importing GIS for public welfare are Google Maps, Yahoo Maps and Google Earth. 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. Each type of data of an area is stored as a separate 'layer' of the map. In GIS, layers may be used some times and removed according to need. Examples are hospitals, schools, water bodies, parks and ATMs. The computers can create maps showing any combination of data.

7.3 Bhuvan

Bhuvan (Sanskrit for Earth) is a free internet based computer application launched by the Indian Space Research Organization (ISRO) on August 12th 2009. 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. 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). Bhuvan has tremendous uses for scientists, academicians, policy makers and the general public.

Recap

Surveying is the process of recording the measurements of a land area. Anaximander was the first ancient Greek to draw a map of the known world. Maps can show the whole or a part of the world. The art and science of map making is called Cartography. A map should include certain components namely, the title, scale, direction, grid reference, projection, legend, conventional signs and symbols. Grids are sets of lines for defining a location on a map. Remote sensing means acquiring information of things / places from a distance. Global Navigation Satellite System (GNSS) helps to locate, monitor and track a user's vehicle anywhere in the world. GIS is a combination of computer hardware, software, geographic data and the personnel.

EXERCISE

Exercise 1. Choose the correct answer

1. ______ indicates the purpose or theme of the map.

a) Title b) Scale c) Direction d) Legend

2. 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

3. GPS consists of a constellation of ______ satellites.

a) 7 b) 24 c) 32 d) 64 Exercise 2. Match the following

1. The art and science of mapping
2. Actual shape of the earth
3. NAVSTAR

Options: a) USA, b) Geoid, c) Cartography

Exercise 3. Consider the given statements and choose the right option given below

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

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) Exercise 4. Answer in brief

1. What is a map?

2. What are the components of a map?

3. 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.

4. Mention a few surveying instruments.

5. Define remote sensing.

6. What are the components of remote sensing?

Exercise 5. Give Reasons

1. Satellite imageries stimulate mapmaking.

2. Map is the basic tool of a geographer.

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

Exercise 6. Distinguish Between The Following

1. Globe and Map

2. Aerial photographs and satellite imageries

3. GIS and GPS

Exercise 7. Answer in Paragraph

1. What do you mean by the term 'scale of the map'? Explain its classification.

2. Write a note on directions with relevant diagram.

3. Explain the major uses of GPS? Explain about any one.

Exercise 8. Map Exercise

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 degree North, 78 degree East

c. Locate the city approximately on 11 degree North and 76 degree East.

d. Find the latitude and longitude of Kanyakumari and mark it.

Exercise 9. HOTS

1. Can you imagine a world without satellites?

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

REFERENCE BOOKS

1. R.L. Singh, (1992) Elements of Practical Geography, Kalyani Publishers, New Delhi.

2. Pijushkanti Saha and the Partha Basu (2013), 'Advanced Practical Geography – a Laboratory Manual', Books and Allied (P) Ltd., Kolkatta.

3. Anji Reddy, M, (2015) Fourth Edition, Text Book of Remote Sensing and Geographical information systems, BSP Books Pvt. Ltd., Hyderabad.

4. Panda, B.C, (2009), 'Remote sensing principles and Applications', Viva books, New Delhi.

5. Misra, R.P and Ramesh, A, (1969) 'Fundamentals of cartography' Prasaranga University of Mysore, Mysore

6. LO, C.P and Albert, K.W, Young (2002) 'Concepts and Techniques of Geographic Information Systems' Prentice – Hall of India Pvt. Ltd., New Delhi.

INTERNET RESOURCES

www.usgs.gov.in

www.nasa.gov.in

www.surveyofindia.gov.in

https://bhuvan.nrsc.gov.in

https://www.isro.gov.in

ICT CORNER MAPPING SKILL

Procedure

Step 1: Use the URL or scan the QR code to open the activity page.

Step 2: Click 'Polyline' button. Draw a poly line between any two favourable places.

Step 3: After finishing, the Poly line shows the measurement of distance as miles and kilometres.

Step 4: Click '+' and '-'button to zoom in and zoom out.

URL: https://mapmaker.nationalgeographic.org/ (or) scan the QR Code

*Pictures are indicatives only

UNIT 8 Disaster Management: Responding to Disasters

Book-back Exercises — Questions & Answers

Answers generated strictly from the Samacheer Kalvi textbook content. Attempt each question first, then click "Show Answer" to check.

1. Choose the correct answer

1. _______ indicates the purpose or theme of the map.

a) Title b) Scale c) Direction d) Legend

Answer: a) Title

Explanation: Title indicates the purpose or theme of the map. Examples include India – Physical, World – Political, Tamil Nadu – Transport.

2. 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

Explanation: Conventional signs and symbols are standard symbols used on a map and explained in the legend to convey a definite meaning.

3. GPS consists of a constellation of _______ satellites.

a) 7 b) 24 c) 32 d) 64

Answer: b) 24

Explanation: NAVSTAR is a network of 24 United States satellites in six different orbits in space flying 20,350 km above the surface of the Earth.

(2). Match the following

Match the following:

1. The art and science of mapping	a) USA
2. Actual shape of the earth	b) Geoid
3. NAVSTAR	c) Cartography

Answers: 1-c, 2-b, 3-a

(3). Consider the given statements and choose the right option given below

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: (b) Both (A) and (R) are true; (R) does not explain (A)

Explanation: Grid systems help locate places through coordinates formed by intersecting lines, while Northings and Eastings refer to the directional lines themselves.

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

Explanation: The legend of a map helps to understand the map details which are placed at the left or right corner at the bottom of the map.

4. Answer in brief

1. What is a map?

Answer: A map is defined as the miniature image of the 3 dimensional earth's surface on a paper/cloth or any flat surface. Maps are drawings of an area as seen from above and are drawn to a scale and direction.

2. What are the components of a map?

Answer: A map should include the following components: title, scale, direction, grid system, projection, legend, and conventional signs and symbols.

3. 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: Given: Map distance = 5 cm, Ground distance = 5 km = 500,000 cm. RF = Distance on map / Distance on ground = 5 cm / 500,000 cm = 1:100,000

4. Mention a few surveying instruments.

Answer: Geographers mainly use Chain, Prismatic compass, Plane table, Dumpy level, Abney level, Clinometre, Theodolite, Total Station and GNSS for surveying.

5. Define remote sensing.

Answer: Remote Sensing refers to the observation and measurement of earthly objects without touching them. It means acquiring information of things/places from a distance, using a variety of tools and methods.

6. What are the components of remote sensing?

Answer: The components include aerial photography using cameras mounted on balloons, helicopters, aeroplanes and drones, and satellite remote sensing using artificial satellites orbiting the Earth.

(5). Give Reasons

1. Satellite imageries stimulate mapmaking.

Answer: Satellites collect large amount of data of the entire area in a short span, allow global coverage, can repeat and revisit easily, and all information is digital which can be easily integrated with software for image improvement.

2. Map is the basic tool of a geographer.

Answer: A map illustrates the earth's surface clearly and effectively through a combination of drawings, words and symbols. Maps form an integral part of teaching geography and serve as a location guide.

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

Answer: The location of a place can be simply defined by its latitude and longitude. The grid system helps in locating places precisely using coordinates where vertical and horizontal lines intersect.

(6). Distinguish Between The Following

1. Globe and Map

Answer: A globe shows the spherical shape of Earth while a map is the miniature image of the 3 dimensional earth's surface on a flat surface like paper or cloth. Maps require projection to show the spherical earth on a flat surface.

2. Aerial photographs and satellite imageries

Answer: Aerial photography uses cameras mounted on low flying birds, balloons, helicopters and aeroplanes, covers small areas, and is affected by weather. Satellite remote sensing uses artificial satellites orbiting Earth, provides global coverage, and is not affected by weather.

3. GIS and GPS

Answer: GIS is a computer-based tool for managing large amounts of geographic data through software and hardware. GPS is a navigation system using 24 satellites to provide location, tracking and timing information anywhere in the world.

(7). Answer in Paragraph

1. What do you mean by the term 'scale of the map'? Explain its classification.

Answer: Scale makes it possible to reduce the size of the whole earth to show it on a piece of paper. A scale is a ratio between the actual distance on the map to the actual distance on the ground. Scales can be represented in three methods: Statement scale describes the relationship in words like 1cm = 10 km, Representative Fraction (R.F.) describes the proportion as 1:100000, and Linear or Graphical scale is represented by a straight line divided into equal parts for direct measurement.

2. Write a note on directions with relevant diagram.

Answer: Maps are drawn normally with north orientation. North direction points towards the North Pole. If you face north, on your right will be east, left will be west, and back will be south. These four main directions are called cardinal directions. Direction is indicated by a North-South line with an arrow head pointing north. A memory technique is "Never Eat Soggy Wheaties" for North, East, South and West.

3. Explain the major uses of GPS? Explain about any one.

Answer: GPS has applications in mobile phones, watches, vehicles and ATMs. It provides accurate transport data including distance, route and direction. It helps in military searches and rescue operations, works as a tourist guide, assists during accidents and emergency services, and aids in weather forecasting and earthquake monitoring. GPS uses 24 NAVSTAR satellites orbiting 20,350 km above Earth, circling twice daily to provide continuous worldwide coverage.

📝 Summary

1. A map is the basic tool of a geographer that illustrates the earth's surface through drawings, words and symbols, serving as a location guide and miniature 3-dimensional representation of earth on a flat surface.
2. Essential map components include title, scale, direction, grid system, projection, legend, and conventional signs and symbols, each serving specific purposes for map interpretation.
3. Map scales can be represented in three methods: Statement scale (1cm = 10 km), Representative Fraction or R.F. (1:100000), and Linear or Graphical scale showing equal divisions for direct distance measurement.
4. Direction on maps is indicated by cardinal directions (North, South, East, West) with North typically oriented towards the North Pole and represented by an arrow head on a North-South line.
5. Modern mapping incorporates advanced techniques including surveying, aerial photography, satellite remote sensing, GIS, GNSS, and GPS for acquiring accurate geographical data and creating comprehensive maps.