LATITUDE AND LONGITUDE

Any location on earth is described by two no’s : 

LATITUDE AND LONGITUDE

# Latitude #

It is the angular distance of a point on the Earth’s surface. It is measured in Degree. It varies from 0⁰ N to 90⁰ N and 0⁰ S to 90⁰ S.

# Longitude #

It is an angular distance measured in degrees along the equator East or West of the Prime Meridian (0°).

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# Latitude #

► Needy and Relevant Key Points Regarding Latitude :

• The ‘Equator’ represents 0 latitude
• Tropic of cancer ☛ 23½⁰ N
• Tropic of Capricorn ☛ 23½° S
• Arctic Circle ☛ 66½° N
• Antarctic Circle ☛ 66½° S
• 1°=111 km

► Equator is the greatest circle that can be drawn on Earth’s surface.◄

☑ The latitudes are also known as Temperature Coordination because with the increase in latitudinal distance towards the poles, the temperature reduces.

• There are total 181 latitude including the Equator.
• Each parallel of latitude is a circle, but they are not equal. The circle reduces when we move towards the Poles

►The distance b/w any two parallels of latitude is always equal.◄

Key Points :-

► The middle sun is exactly overhead at least once a year on all latitudes in b/w the tropic of cancer and the tropic of Capricorn. This area, therefore receives the maximum heat and is called the Torrid Zone (Tropical Zone).

► The areas bounded by the tropic of cancer & the arctic circle in the Northern hemisphere, and the tropic of Capricorn & the Antarctic circle in the Southern hemisphere, have moderate temperatures, hence called Temperate Zones (Mild Zone).

► Area bounded by the Arctic circle & North pole, and the Antarctic circle & South pole are called Frigid Zones. These zones are very cold as the sun does not rise above the Horizon.

# Longitude #

It is an angular distance measured in degrees along the equator East or West of the Prime Meridian (0°).

► It varies from 0° E to 180° E and 0° W to 180° W.

► It is also called as Time Coordinates. 

► They are also called ‘Meridians’.

☑ Meridian :- ‘Meridians’ are a series of semi-circles that run from pole to pole passing through the equator.

► There are 360° meridians of longitude.

► The prime meridian is longitude of 0° and is known as the Greenwich line as it passes through Greenwich near London, where the British Royal Observatory is located.

GLOBE WITH DESCRIPTION

☑ 0° Meridian (Prime Meridian) ☛ Greenwich

☑ Both 0° & 180° are known as Antipodal Points.

► Longitudes have one very important function i.e. they determine local time in relation to Greenwich Mean Time (GMT).

► In India, the longitude of 82½° E is treated as the Standard Meridian.

☑ International Standard Time (IST) : The local time at which meridian is taken as the standard time for the whole country. It is known as the International Standard Time (IST).

► The Earth is divided into 24 longitudinal zones each being apart 15° or 1 hr apart in time.

► Russia has 11 time zones while USA and Canada have 5 time zones.

► India, whose longitudinal extent is approx. 30°, has adopt only 1 time zone; selecting the 82.5 / 82½° for the standard time, which is 5 hours & 30 minutes ahead of GMT. 

KEY POINTS :-

Places that are on the same meridian have the same local (Sun) time. Since the earth makes one complete revolution of 360° in 24 hours, it passes through 15° in 1 hr or 1° in 4 minutes.

► The Earth rotates from the West to East; hence places east of Greenwich see the Sun later and lost time.

►E.G.A. (East-Gain-Add)◄

►W.L.S. (West-Lose-Subtract). ◄ So, if it is noon in London (near 0°), 15° east will be 1 hour ahead of London. This means that here the time will be 1 p.m. and Chennai of 80° E will be 5 hours 20 minutes ahead. This means here the time will be 5:20 pm.