Chapter 1 Class 6 Geography is about maps, globes, directions, symbols, scale, latitudes, longitudes, coordinates and time zones. This chapter is part of Class 6 NCERT textbook of Social Studies. Here, you can read notes of this.
Introduction
When we visit a new place, we often use a map to find our way. A map helps us locate places, understand directions and estimate distances.
According to the ancient Indian mathematician and astronomer Āryabhaṭa (about 500 CE), the Earth is spherical and exists in space surrounded by all living beings.
What is a Map?
A map is a representation or drawing of an area on a flat surface.
A Map May Show
- A Village
- A Town
- A District
- A State
- A Country
- The Whole World
A map shows the Earth’s surface as if we are looking at it from above.
Definition
Map: A drawing that shows the location of places and helps us find directions and distances.
Atlas
An atlas is a book or collection of maps.
Examples
- School Atlas
- World Atlas
- India Atlas
Types of Maps
A. Physical Maps
Physical maps show natural features such as:
- Mountains
- Rivers
- Oceans
- Plains
Example
A map showing the Himalayas, rivers and deserts of India.
B. Political Maps
Political maps show:
- Countries
- States
- Boundaries
- Capitals
- Cities
Example
A map showing all the States and Union Territories of India.
C. Thematic Maps
Thematic maps show a particular type of information.
Examples
- Population Map
- Rainfall Map
- Forest Map
- Crop Map
| Type of Map | Shows |
|---|---|
| Physical Map | Natural features such as mountains, rivers, oceans and plains. |
| Political Map | Countries, states, boundaries, capitals and cities. |
| Thematic Map | Specific information such as population, rainfall, forests and crops. |
Main Components of a Map
Every map has three important components:
- Distance
- Direction
- Symbols
Distance and Scale
A map is much smaller than the actual area it represents.
To show real distances on a small sheet of paper, maps use a scale.
Example
If 1 cm = 500 m, then every centimetre on the map represents 500 metres on the ground.
Importance of Scale
Scale helps us:
- Measure distances
- Compare locations
- Understand the size of an area
Remember
The actual distance between two places depends on the scale used in the map.
Directions
Maps help us know where places are located.
Cardinal Directions
There are four main directions:
| Direction | Symbol |
|---|---|
| North | N |
| East | E |
| South | S |
| West | W |
Intermediate Directions
Between the four main directions are:
| Direction | Short Form |
|---|---|
| Northeast | NE |
| Southeast | SE |
| Southwest | SW |
| Northwest | NW |
Important Fact
Most maps have an arrow marked N which points towards the north.
Symbols on Maps
Large maps cannot show every object with drawings.
Therefore, map makers use symbols.
Symbols Represent
- Railway Stations
- Schools
- Post Offices
- Roads
- Rivers
- Forests
- Temples
- Police Stations
Why are Symbols Important?
- Save space
- Make maps easy to read
- Are understood by many users
Survey of India
The Survey of India is a government organisation that prepares maps and has fixed standard symbols for maps of India.
Common Symbols
| Feature | Symbol Used For |
|---|---|
| Railway Line | Railway Routes |
| Roads | Metalled and Unmetalled Roads |
| River | Water Bodies |
| Temple | Religious Places |
| Police Station | Security Services |
| Trees | Vegetation |
Mapping the Earth
The Earth is not flat. It is nearly spherical in shape.
Because of this, representing the Earth accurately on a flat sheet of paper is difficult.
Example
An orange peel cannot be flattened completely without tearing it. Similarly, the Earth’s curved surface cannot be perfectly shown on a flat map.
Globe
A globe is a sphere on which a map is drawn.
Advantages of a Globe
- Has the same shape as the Earth.
- Represents the Earth more accurately than a flat map.
- Shows continents and oceans correctly.
Understanding Coordinates
To locate a place exactly, we use a system called coordinates.
Just as shops in a market or squares on a chessboard can be identified by rows and columns, locations on Earth can also be identified precisely.
Latitudes
What is Latitude?
Latitude measures the distance of a place from the Equator.
Important Latitudes
| Latitude | Value |
|---|---|
| Equator | 0° |
| North Pole | 90°N |
| South Pole | 90°S |
Parallels of Latitude
Imaginary lines drawn parallel to the Equator are called parallels of latitude.
Features of Parallels of Latitude
- Run from east to west.
- Form complete circles.
- Become smaller towards the poles.
- The Equator is the largest parallel.
Latitude and Climate
Latitude affects climate because different parts of the Earth receive different amounts of sunlight.
Torrid Zone
- Located near the Equator.
- Has a hot climate.
- Receives more sunlight throughout the year.
Temperate Zone
- Located away from the Equator.
- Has a moderate climate.
Frigid Zone
- Located near the poles.
- Has a very cold climate.
Longitudes
What is Longitude?
Longitude measures the distance of a place from the Prime Meridian.
Meridians of Longitude
- Run from the North Pole to the South Pole.
- Are half circles.
- All are equal in length.
Prime Meridian
The Prime Meridian is the reference line used for measuring longitude.
Important Facts
- Longitude = 0°
- Passes through Greenwich in London, England.
- Also called the Greenwich Meridian.
Measuring Longitude
Longitude is measured:
- Eastward from 0° to 180°E
- Westward from 0° to 180°W
Examples
| City | Longitude |
|---|---|
| Delhi | 77°E |
| New York | 74°W |
| Tokyo | 140°E |
Coordinates of a Place
Latitude and longitude together form the coordinates of a place.
Example
Delhi:
Latitude = 29°N
Longitude = 77°E
Thus, Delhi can be located precisely on the Earth.
Grid Lines
The network formed by latitudes and longitudes on the globe is called a grid.
The lines that form this network are known as grid lines.
Importance of Grid Lines
- Help locate any place accurately.
- Provide a systematic way of finding locations.
- Make map reading easier and more precise.
Hemispheres
The Earth is divided into hemispheres.
Equator Divides the Earth Into
- Northern Hemisphere
- Southern Hemisphere
Prime Meridian Divides the Earth Into
- Eastern Hemisphere
- Western Hemisphere
Ancient Indian Prime Meridian
Long before Greenwich became the Prime Meridian, India used its own prime meridian called Madhya Rekhā (Middle Line).
Important Facts
- Passed through Ujjayinī (Ujjain).
- Used by Indian astronomers.
- Varāhamihira worked at Ujjain about 1,500 years ago.
India’s Location
Latitudinal Extent
India extends approximately from:
- 8°N to 37°N
Longitudinal Extent
India extends approximately from:
- 68°E to 97°E
Understanding Time Zones
The Earth rotates from west to east.
Important Facts
- The Earth rotates 360° in 24 hours.
- Therefore, the Earth rotates 15° in 1 hour.
Local Time
Different longitudes experience different times because the Earth rotates continuously.
Example
If it is:
- 12 noon at Greenwich
- 1 pm at 15°E
- 2 pm at 30°E
Thus, longitude helps determine local time.
Standard Time
Using different local times within a country would create confusion.
Therefore, countries adopt a common standard time.
Indian Standard Time (IST)
IST is:
IST = GMT + 5:30
Indian Standard Time is 5 hours 30 minutes ahead of Greenwich Mean Time (GMT).
Time Zones
The world is divided into different time zones.
Why Are Time Zones Needed?
Different places receive sunlight at different times because the Earth rotates.
Important Fact
Some large countries have many time zones.
| Country | Number of Time Zones |
|---|---|
| USA | 6 |
| Russia | 11 |
International Date Line (IDL)
The International Date Line lies approximately at 180° longitude.
Importance
Crossing the International Date Line changes the date.
Rule
| Direction of Travel | Change in Date |
|---|---|
| Travelling Eastward | Subtract One Day |
| Travelling Westward | Add One Day |
Important Note
The International Date Line is not perfectly straight. It bends in some places to avoid dividing countries and island groups into different dates.