GEOGRAPHIC GRID – LATITUDES AND LONGITUDES
The network of parallels of latitude and medians of longitude is called geographic grid
Parallels of latitude –
Latitude is an angular distance north or south of the equator measured from the centre of
the earth.
Equator is the longest latitude.
180 parallels of latitude.
Length of 600 latitude is half the length of the Equator
Length of the arc of one-degree latitude is approx. 111 km
Latitude can be calculated with reference to the zenith distance (the angle that the sun
makes with the zenith of a place at 12 noon) and the declination of the sun (the angle that
the sun makes north or south of the equator on a particular day)
Equator is an imaginary line that divides the earth into northern and southern hemisphere.
It is reference line for measuring distances north or south
Latitude and Heat Zones of the Earth –
Torrid (Hot) Zone - Between Tropic of Cancer and Tropic of Capricorn. Maximum amount of
heat. Called the area of low latitudes
Temperature Zone – Between Tropic of Cancer and Artic Circle in Northern Hemisphere
and the Tropic of Capricorn and Antarctic Circle in the Southern Hemisphere. Temperature
is less hot and moderate. Also called Temperate Zone.
1 1
Equator (00), Tropic of Cancer (23 0 N), Tropic of Capricorn (23 0 S), Arctic Circle
2 2
10 10
(66 N), Antarctic Circle (66 S)
2 2
Frigid Zone – Between the Arctic Circle and North Pole in Northern Hemisphere and
Antarctic Circle and South Pole in Southern Hemisphere, rays of Sun are very slanted and
temperature is very cold
Importance of Latitude –
Latitude has a direct impact on the climate of a place. Places away from Equator receive
less sunlight and have a cold climate. Places near the Equator receive more sunlight and
are hotter. Equator receives the most amount of sunlight and is very hot.
It enables us to find the exact location of a place.
Prime Meridian/Greenwich Meridian –
Prime Meridian is the reference line for measuring distances east or west.
It is an imaginary line passing through Greenwich near London
Joins the North Pole and South Pole
, There are 360 longitudes
India lies in Eastern Hemisphere. South Africa lies in Western Hemisphere.
Longitudes –
Longitude is an angular distance east or west of the Prime Meridian
The lines of longitude are called meridians because all places situated at a given meridian
experience midday at the same time
Longitude of Allahabad, Mirzapur is 820 30’ E
Basis Latitude Longitude
Meaning Latitude is an angular distance Longitude is an angular distance east
north or south of the equator or west of the Prime Meridian
measured from the centre of the
earth.
Name Lines of latitude are referred as Lines of longitude are called
parallels meridians
Reference Point Equator Prime Meridian
Division of Earth Divides the earth into Northern Divides the earth into Eastern and
and Southern Hemisphere Western Hemisphere
Number 180 360
Importance Divides the earth into 3 heat Helps to determine the time of a
zones, has a direct impact on place
climate, exact location of places
Equality Not equal Equal in length
Important lines Equator, Tropic of Cancer, Tropic Prime Meridian
of Capricorn, Arctic Circle and
Antarctic Circle
Longitude and Time –
Time is measured on the basis of the overhead sun. When the sun is overhead at a place, it
is 12 non and this time is called the local time
EAST ADD – WEST SUBTRACT
SAME HEMISPHERE SUBTRACT AND DIFFERENT HEMISPHERE ADD
Local Time and Standard Time –
A uniform time throughout the country is followed in most parts of the Earth. This time is
called the Standard Time. It is based on the central meridian of the country.
The central meridian is called a Standard Meridian.
Indian Standard Time –
, The central meridian for IST is 820 30’ E
Greenwich Meridian (GMT) passes through Great Britain, countries of West Europe and
West Africa
Time Zones
A time zone is a geographical region where clock records the same time
The longitudinal stretch of Russia is 1650. It has about 11 time zones
Canada and USA have 5 time zones – Atlantic, Eastern, Central, Mountain and Pacific zones.
International Date Line –
The longitude of 1800 is selected for counting the dates and is called the International Date
Line
The International Date Line is also adjusted so that it does not bisect any country and
each country has only one sate at a time
The Great Circle and The Small Circle –
A circle dividing the earth into two equal parts is called a Great Circle
Equator and all longitudes are Great Circle
A small circle in the Earth is one that does not divide it into two equal parts
All latitudes except Equator is a small circle
Travelers and navigators going to distant places try to follow the shortest route between
various places. They are the Great Circle routes. They are basically the shortest routes
between various places. Ships and aircrafts follow great circle routes as far as possible to
make the journeys economical.
Rotation and Revolution of The Earth -
“Rotation is the turning around of the Earth on its from west to east.”
“The movement of the Earth around the Sun is called the revolution.”
Tilt of the Earth’s Axis-
The tilting of the axis at 66 ½ ° with the plane of Earth’s orbit is called the Inclination of the
Earth’s Axis
Effects of Rotation-
East-West movement- the earth rotates from east to west hence we see the sun rising from
the east and sets in the west.
Day and Night- important effect of earthly rotation is diurnal alteration of light and darkness
as portions of Earth’s surface are turned first toward and then away from the Sun. This
variation in exposure to sunlight greatly influences local temperature, humidity and wind
movements.
Circulation of air and water- the earth’s rotation causes a consistent change in the direction
of the flow of winds and water of the oceans. Winds and Ocean currents are deflected
The network of parallels of latitude and medians of longitude is called geographic grid
Parallels of latitude –
Latitude is an angular distance north or south of the equator measured from the centre of
the earth.
Equator is the longest latitude.
180 parallels of latitude.
Length of 600 latitude is half the length of the Equator
Length of the arc of one-degree latitude is approx. 111 km
Latitude can be calculated with reference to the zenith distance (the angle that the sun
makes with the zenith of a place at 12 noon) and the declination of the sun (the angle that
the sun makes north or south of the equator on a particular day)
Equator is an imaginary line that divides the earth into northern and southern hemisphere.
It is reference line for measuring distances north or south
Latitude and Heat Zones of the Earth –
Torrid (Hot) Zone - Between Tropic of Cancer and Tropic of Capricorn. Maximum amount of
heat. Called the area of low latitudes
Temperature Zone – Between Tropic of Cancer and Artic Circle in Northern Hemisphere
and the Tropic of Capricorn and Antarctic Circle in the Southern Hemisphere. Temperature
is less hot and moderate. Also called Temperate Zone.
1 1
Equator (00), Tropic of Cancer (23 0 N), Tropic of Capricorn (23 0 S), Arctic Circle
2 2
10 10
(66 N), Antarctic Circle (66 S)
2 2
Frigid Zone – Between the Arctic Circle and North Pole in Northern Hemisphere and
Antarctic Circle and South Pole in Southern Hemisphere, rays of Sun are very slanted and
temperature is very cold
Importance of Latitude –
Latitude has a direct impact on the climate of a place. Places away from Equator receive
less sunlight and have a cold climate. Places near the Equator receive more sunlight and
are hotter. Equator receives the most amount of sunlight and is very hot.
It enables us to find the exact location of a place.
Prime Meridian/Greenwich Meridian –
Prime Meridian is the reference line for measuring distances east or west.
It is an imaginary line passing through Greenwich near London
Joins the North Pole and South Pole
, There are 360 longitudes
India lies in Eastern Hemisphere. South Africa lies in Western Hemisphere.
Longitudes –
Longitude is an angular distance east or west of the Prime Meridian
The lines of longitude are called meridians because all places situated at a given meridian
experience midday at the same time
Longitude of Allahabad, Mirzapur is 820 30’ E
Basis Latitude Longitude
Meaning Latitude is an angular distance Longitude is an angular distance east
north or south of the equator or west of the Prime Meridian
measured from the centre of the
earth.
Name Lines of latitude are referred as Lines of longitude are called
parallels meridians
Reference Point Equator Prime Meridian
Division of Earth Divides the earth into Northern Divides the earth into Eastern and
and Southern Hemisphere Western Hemisphere
Number 180 360
Importance Divides the earth into 3 heat Helps to determine the time of a
zones, has a direct impact on place
climate, exact location of places
Equality Not equal Equal in length
Important lines Equator, Tropic of Cancer, Tropic Prime Meridian
of Capricorn, Arctic Circle and
Antarctic Circle
Longitude and Time –
Time is measured on the basis of the overhead sun. When the sun is overhead at a place, it
is 12 non and this time is called the local time
EAST ADD – WEST SUBTRACT
SAME HEMISPHERE SUBTRACT AND DIFFERENT HEMISPHERE ADD
Local Time and Standard Time –
A uniform time throughout the country is followed in most parts of the Earth. This time is
called the Standard Time. It is based on the central meridian of the country.
The central meridian is called a Standard Meridian.
Indian Standard Time –
, The central meridian for IST is 820 30’ E
Greenwich Meridian (GMT) passes through Great Britain, countries of West Europe and
West Africa
Time Zones
A time zone is a geographical region where clock records the same time
The longitudinal stretch of Russia is 1650. It has about 11 time zones
Canada and USA have 5 time zones – Atlantic, Eastern, Central, Mountain and Pacific zones.
International Date Line –
The longitude of 1800 is selected for counting the dates and is called the International Date
Line
The International Date Line is also adjusted so that it does not bisect any country and
each country has only one sate at a time
The Great Circle and The Small Circle –
A circle dividing the earth into two equal parts is called a Great Circle
Equator and all longitudes are Great Circle
A small circle in the Earth is one that does not divide it into two equal parts
All latitudes except Equator is a small circle
Travelers and navigators going to distant places try to follow the shortest route between
various places. They are the Great Circle routes. They are basically the shortest routes
between various places. Ships and aircrafts follow great circle routes as far as possible to
make the journeys economical.
Rotation and Revolution of The Earth -
“Rotation is the turning around of the Earth on its from west to east.”
“The movement of the Earth around the Sun is called the revolution.”
Tilt of the Earth’s Axis-
The tilting of the axis at 66 ½ ° with the plane of Earth’s orbit is called the Inclination of the
Earth’s Axis
Effects of Rotation-
East-West movement- the earth rotates from east to west hence we see the sun rising from
the east and sets in the west.
Day and Night- important effect of earthly rotation is diurnal alteration of light and darkness
as portions of Earth’s surface are turned first toward and then away from the Sun. This
variation in exposure to sunlight greatly influences local temperature, humidity and wind
movements.
Circulation of air and water- the earth’s rotation causes a consistent change in the direction
of the flow of winds and water of the oceans. Winds and Ocean currents are deflected
