Introduction to Maps, Class 11 Practical Work in Geography

What Introduction to Maps is about

Key concepts

Map, globe and sketch

NCERT section Introduction to Maps

• The shape of the earth is a geoid (three-dimensional); a globe represents it best.
• A map is a simplified depiction of the whole or part of the earth on paper: a 2-D form of the 3-D earth. So it needs a map projection (Chapter 4).
• Features cannot be shown in true size, so maps are drawn at a reduced scale (a plan of your school at actual size would be as big as the campus).
• Each point on the paper corresponds to the actual ground position through scale and projection.
• Features are simplified with symbols, colours and shades.

Definition: a map is a selective, symbolised and generalised representation of the whole or part of the earth's surface on a plane surface at a reduced scale.

Sketch: a simple network of lines and polygons without a scale is not a map but a sketch (glossary: a freehand map that does not preserve true scale or orientation; Figure 1.2 compares a sketch of Delhi's environs with a map of Delhi).

Worked example

A student draws the route from home to school freehand, showing shops and turns but no scale. Is it a map? Explain. (2 marks)

Try it first, then show the solutionSolution

1. NCERT says a network of lines and polygons without a scale is not a map.
2. A freehand drawing that does not preserve true scale or orientation is a sketch.

Answer: No; without a scale it is a sketch.

Essentials of map making

NCERT section Essentials of Map Making

Cartography is the art, science and technology of making maps. Five processes common to all maps:

Essential	What it involves
Scale	The first decision; all maps are reductions. Scale sets the limits of information and the degree of reality a map can show (Figure 1.3 compares sheets at different scales)
Map projection	Transforming the curved geoid onto a plane; this unavoidably changes directions, distances, areas and shapes; the choice, use and construction of projections is of prime importance
Generalisation	Every map has a purpose: general purpose maps (relief, drainage, vegetation, settlements, transport) or special purpose (thematic) maps (population density, soils, industries). The cartographer selects relevant information and simplifies it
Map design	Planning graphic characteristics: symbols (size and form), lettering, line widths, colours and shades, arrangement of elements, the legend; needs understanding of graphic communication
Construction and production	Drawing and reproducing maps: earlier by pen and ink and mechanical printing; now computer-assisted mapping and photo-printing

Worked example

Why is scale called the first decision of a map-maker? (2 marks)

Try it first, then show the solutionSolution

1. All maps are reductions, so the map-maker must decide how much to reduce.
2. The scale sets the limits of information and the degree of reality the map can show; everything else (detail, symbols, generalisation) depends on it.

Answer: It fixes how much detail and reality the map can contain.

History of map making

NCERT section History of Map Making

World:

• As old as humankind; the oldest map: a clay tablet from Mesopotamia, 2,500 BC.
• Ptolemy's Map of the World (Figure 1.4).
• Greek and Arab geographers laid the foundation of modern cartography: measuring the earth's circumference and using geographical coordinates.
• Early modern period: efforts to reduce errors of transforming the geoid; projections for true directions, correct distances and accurate areas.
• 19th and 20th centuries: aerial photography supplemented ground surveys.

India:

• Foundations in the Vedic period (astronomical truths and cosmology), crystallised into siddhantas (laws) in the works of Aryabhata, Varahamihira and Bhaskara.
• Ancient scholars divided the known world into seven dwipas (Figure 1.5); the Mahabharata conceived a round world surrounded by water (Figure 1.6).
• Medieval: Todarmal pioneered land surveying and map-making for revenue collection; Sher Shah Suri's revenue maps enriched techniques.
• Survey of India set up in 1767; intensive topographical surveys culminated in the map of Hindustan (1785); today it maps the whole country at different scales.

Worked example

Name two contributions of Greek and Arab geographers to cartography. (1 mark)

Try it first, then show the solutionSolution

1. NCERT credits them with laying the foundation of modern cartography.
2. They measured the earth's circumference and used geographical coordinates in map-making.

Answer: Measuring the earth's circumference and using geographical coordinates.

Types of maps based on scale

NCERT section Essentials of Map Making

Large-scale maps (small areas, more detail)	Small-scale maps (large areas, generalised)
Topographical maps at 1:250,000, 1:50,000, 1:25,000; village maps, city zonal plans and house plans at 1:4,000, 1:2,000, 1:500	Atlas maps, wall maps

Large-scale types:

• Cadastral maps: from French *cadastre*, 'register of territorial property'. Show ownership of land: field boundaries and house plans; prepared by government to realise revenue and taxes and record ownership; very large scale: villages 1:4,000, city plans 1:2,000 and larger (glossary: 1:500 to 1:4,000).
• Topographical maps: fairly large scale; based on precise surveys; produced as map series by national agencies; the Survey of India maps at 1:250,000, 1:50,000 and 1:25,000; uniform colours and symbols for relief, drainage, farmland, forest, settlements, communications, schools, post offices.

Small-scale types:

• Wall maps: on large paper or plastic for classrooms; scale smaller than topographical but larger than atlas maps.
• Atlas maps: very small scale; highly generalised; a graphic encyclopaedia of location, relief, drainage, climate, vegetation, cities, population, industries, transport, tourism and heritage sites.

Worked example

A map shows each field boundary in a village with plot numbers at 1:4,000. Name its type and purpose. (2 marks)

Try it first, then show the solutionSolution

1. A very large-scale map (1:4,000) showing ownership of land parcels is a cadastral map.
2. Its purpose is to record ownership and help the government realise land revenue and taxes.

Answer: Cadastral map, for ownership records and revenue.

Types of maps based on function

NCERT section Essentials of Map Making

Physical maps (natural features):

Map	Shows
Relief	General topography: mountains, valleys, plains, plateaus, drainage (relief and slope map of Nagpur district, Figure 1.7)
Geological	Geological structures, rock types (rocks and minerals of Nagpur, Figure 1.8)
Climatic	Climatic regions; temperature, rainfall, cloudiness, humidity, wind direction and speed (Figure 1.9)
Soil	Distribution and properties of soils (Figure 1.10)

Cultural maps (human-made features): population, sex and age, social and religious composition, literacy, education, occupations, settlements, services, transport, production and flows of commodities.

Map	Shows
Political	Administrative divisions (country, state, district); help administration plan and manage
Population	Distribution, density, growth, age-sex composition, religious, linguistic and social groups, occupations; most significant role in planning (Figure 1.11)
Economic	Production and distribution of crops and minerals, industries, markets, trade routes, commodity flows (land use and cropping, industries of Nagpur)
Transportation	Roads, railway lines, stations, airports

Worked example

Classify these maps as physical or cultural: (a) a soil map, (b) a map of literacy rates, (c) a relief map, (d) a railway map. (2 marks)

Try it first, then show the solutionSolution

1. Soil and relief maps show natural features: physical.
2. Literacy (population characteristics) and railway (transportation) maps show human-made features: cultural.

Answer: (a) physical, (b) cultural, (c) physical, (d) cultural.

Uses of maps: distance, direction and area

NCERT section Uses of Maps

Geographers, planners and resource scientists use maps to measure distance, direction and area.

Distance:

• Straight-line features (roads, railways, canals): measure directly with a pair of dividers or a scale.
• Erratic or zigzag features (coastlines, rivers, streams): lay a thread along the line from start to end, stretch it and measure; or use a rotameter, whose wheel is run along the route.
• Then convert map distance to ground distance using the scale.

Direction:

• An imaginary straight line showing angular position relative to a base direction.
• North is the zero (base) direction; every map shows north.
• Cardinal points: North, South, East, West; intermediate directions lie between them (Figure 1.14).

Area:

• Squares method (simple but not very accurate): place graph paper under the map (on an illuminated tracing table) or trace the area onto squared paper; count whole squares and partial squares:

Area = (sum of whole squares + sum of partial squares ÷ 2) × area represented by one square (from the map scale).

• Polar planimeter (Box 1.1): a rod with one end fixed to a radial arc; trace the perimeter clockwise back to the starting point; the difference in dial readings × the instrument's constant gives the area in square inches or centimetres.

Worked example

On a map of scale 1:50,000, a winding river is traced with a thread that measures 7.4 cm. Find its ground length. (2 marks)

Try it first, then show the solutionSolution

1. 1 cm on the map = 50,000 cm = 0.5 km on the ground.
2. Length = 7.4 × 0.5 = 3.7 km.

Answer: 3.7 km.

Introduction to Maps in real life

Each concept, met in an everyday situation. Read the situation, answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Topics in this chapter

• Types of Maps by Scale and Function: Cadastral, Topographical, Wall, Atlas, Physical and Cultural Maps
• What is a Map? Map versus Sketch, the Five Essentials of Map Making and the History of Cartography

Introduction to Maps: key facts

Definition of a map

Selective + symbolised + generalised representation, on a plane surface, at a reduced scale

No scale = sketch.

Five essentials

1. 1.Scale
2. 2.projection
3. 3.generalisation
4. 4.design
5. 5.construction and production

Scale is the first decision.

Large-scale examples

Topographical 1:250,000, 1:50,000, 1:25,000; cadastral 1:4,000 (village), 1:2,000 and larger (city)

Glossary: cadastral 1:500 to 1:4,000.

Scale order of small-scale maps

Topographical > wall > atlas (in scale)

Atlas maps are very small scale.

Ground distance

$Grounddistance=mapdistance\times scaledenominator(convertunits)$

1:50,000 → 1 cm = 0.5 km.

Area by squares

$Area=(wholesquares+partialsquares÷2)\times groundareaofonesquare$

Simple but not very accurate.

Polar planimeter

$Area=(finalreading-initialreading)\times instrumentconstant$

Trace the perimeter clockwise.

History dates

Mesopotamia clay tablet 2,500 BC; Survey of India 1767; map of Hindustan 1785

Todarmal and Sher Shah Suri: revenue maps.

Introduction to Maps: diagrams to practise

Practise each one on paper: draw it from the checklist, then tick off every label.

Tricks to remember Introduction to Maps

Short memory aids. Say each one aloud once, then use it on a question the same day.

• Five essentials

  'Smart People Generally Design Carefully': Scale, Projection, Generalisation, Design, Construction.

  Use it when: Essentials of map making.

• Map definition

  'S-S-G on a plane, reduced': Selective, Symbolised, Generalised.

  Use it when: Definition of a map.

• Physical maps

  'Real Geography Can't Stop': Relief, Geological, Climatic, Soil.

  Use it when: Physical map types.

• Cultural maps

  'People Pay Every Tax': Political, Population, Economic, Transportation.

  Use it when: Cultural map types.

Where students lose marks in Introduction to Maps

The slips examiners see most often, and what to write instead.

• ✗Mistake: Calling an unscaled drawing a map

  Students think any drawing of places is a map.

  Wrong working

  A freehand drawing of my locality is a map.

  Right working

  Without a scale it is a sketch; a map needs scale, projection and generalised symbols.

  ✓Do this: No scale, no map.

  Usually costs: Marks in an MCQ or viva.

• ✗Mistake: Thinking a small-scale map shows a small area

  The word 'small' misleads.

  Wrong working

  Small-scale maps show small areas in detail.

  Right working

  Small-scale maps (atlas, wall) show large areas with little detail; large-scale maps show small areas in detail.

  ✓Do this: Small scale = small detail, big area.

  Usually costs: Marks in type-of-map questions.

• ✗Mistake: Counting partial squares as whole

  Rushing the area exercise.

  Wrong working

  Area = (whole + partial squares) × square area.

  Right working

  Partial squares are counted as half: (whole + partial ÷ 2) × square area.

  ✓Do this: Halve the partials.

  Usually costs: Marks in the practical exercise.

• ✗Mistake: Listing 'history of maps' as an essential of map making

  It appears in the same chapter.

  Wrong working

  Essentials include the history of maps.

  Right working

  The five essentials are scale, projection, generalisation, design, and construction and production.

  ✓Do this: Learn the five processes.

  Usually costs: Marks in an MCQ.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1. 1.What is the shape of the earth called?Show answer

   A geoid.

2. 2.Where was the oldest map found and of what was it made?Show answer

   Mesopotamia; a clay tablet of 2,500 BC.

3. 3.When was the Survey of India set up?Show answer

   1767.

4. 4.What does 'cadastre' mean?Show answer

   Register of territorial property (French).

5. 5.Which instrument measures distance along a winding line?Show answer

   A rotameter (or a thread).

6. 6.Which direction is the base direction on a map?Show answer

   North (zero direction).

7. 7.Which instrument measures area by tracing a perimeter?Show answer

   The polar planimeter.

Quick revision checklist

The night before the exam: can you do each of these without looking?

• ☐Practical exam chapter: 3 marks in the 30-mark practical.
• ☐Map = selective, symbolised, generalised representation on a plane at a reduced scale; no scale = sketch.
• ☐Five essentials: scale, projection, generalisation, design, construction and production.
• ☐Oldest map: Mesopotamian clay tablet, 2,500 BC; Greeks and Arabs: circumference and coordinates.
• ☐India: siddhantas (Aryabhata, Varahamihira, Bhaskara), seven dwipas, Todarmal, Sher Shah Suri, Survey of India 1767, map of Hindustan 1785.
• ☐Large-scale: cadastral (1:4,000, 1:2,000) and topographical (1:250,000, 1:50,000, 1:25,000).
• ☐Small-scale: wall and atlas maps.
• ☐Physical: relief, geological, climatic, soil; cultural: political, population, economic, transportation.
• ☐Distance: dividers, thread, rotameter; direction: north base, cardinal and intermediate; area: squares, polar planimeter.

Introduction to Maps: frequently asked questions