ENVIRONMENTS THROUGH MAPS ENVIRONMENTS THROUGH MAPS (PART 1)(PART 1)

What is an What is an Atlas?Atlas? What is an What is an Atlas?Atlas? • An atlas is a book of maps and usually contains small-scale maps of countries in the world

• The world map is a common map found in an atlas which shows the locations of oceans and continents

• The bodies of water of the Earth are divided into 5 oceans:• the Atlantic, Pacific, Indian, Arctic and Southern Oceans• The rest of the Earth’s surface is made up of large masses of land called continents (7 in total):• Asia, Australia, Europe, North America, South America, Africa and Antarctica

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66.5°

23.5°

23.5°

66.5°

66.5°

23.5°

23.5°

66.5°

NORTH AMERICA

AFRICA

SOUTH AMERICA

ANTARCTICA

AUSTRALIA

EUROPE ASIA

PACIFIC OCEAN

ATLANTICOCEAN

INDIANOCEAN

SOUTHERNOCEAN

ARCTICOCEAN

Oceans and continents

Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: LatitudesLatitudes Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: LatitudesLatitudes

• Latitudes are imaginary horizontal lines running in an east-west direction round the Earth• The Equator is longest line of latitude which divides the Earth into 2 equal halves

Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: LatitudesLatitudes

Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: LatitudesLatitudes

• The upper half from the Equator to the North Pole is called the Northern Hemisphere

• The lower half from the Equator to the South Pole is called the Southern Hemisphere

Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: LatitudesLatitudes Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: LatitudesLatitudes

• Latitudes are measured in degrees from the Equator• They increase in value as we move from the Equator to the North and South Poles• The important latitudes are: (a) Equator (0o) (b) Tropic of Cancer (23.5oN) (c) Tropic of Capricorn (23.5oS) (d) Arctic Circle (66.5oN) (e) Antarctic Circle (66.5oS) (f) North Pole (90oN) (g) South Pole (90oS)

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Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: Longitudes Longitudes Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: Longitudes Longitudes

• Longitudes are imaginary lines that run in a north-south direction from the North Pole to the South Pole on the Earth’s surface

Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: LongitudesLongitudes Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: LongitudesLongitudes

• Longitudes are measured in degrees east or west from the 0o longitude which is called the Prime Meridian or the Greenwich Meridian • Longitudes west of the Greenwich Meridian are measured from 0o at the Greenwich Meridian to 180oW• Longitudes east of the Greenwich Meridian are measured from 0o at the Greenwich Meridian to 180oE• Both 180oW and 180oE lie on the same longitude

Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: Using Latitudes and Using Latitudes and Longitudes to locate PlacesLongitudes to locate Places

Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: Using Latitudes and Using Latitudes and Longitudes to locate PlacesLongitudes to locate Places

• Latitudes and longitudes cross each other to form a network of lines or a grid• This grid makes it possible to state the exact location of any place on the Earth’s surface• To describe the location of a place on a map, we state the latitude first, followed by the longitude• eg Singapore (position 1.18oN 103.50oE): 1.18onorth of the Equator and 103.50o east of the Greenwich Meridian

Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: The International Date Line (IDL)The International Date Line (IDL)

Locating Places and Features in an Atlas: Locating Places and Features in an Atlas: The International Date Line (IDL)The International Date Line (IDL)

• The International Date Line (IDL) is the 180o longitude that lies directly opposite the Greenwich Meridian• our date moves back by one day when we travel east across the IDL• however our date moves forward by one day when we travel west across the IDL• IDL is not a straight line and bends at certain places to allow these land areas to have the same calendar date

Time Zone VariationsTime Zone VariationsTime Zone VariationsTime Zone Variations• Places on different parts of the Earth experience day and night at different times due to the rotation of the Earth• The world is divided into 24 standard time zones:• each time zone represents 15o longitude, or the distance the Earth rotates in 1 hour• the Greenwich Mean Time (GMT) at 0o longitude, is the base time zone

Time Zone VariationsTime Zone VariationsTime Zone VariationsTime Zone Variations

• The nearest time zone west of Greenwich experiences 1 hour earlier than Greenwich while the nearest time zone east of Greenwich experiences 1 hour later