SESSION 5. REPRESENTING THE EARTH'S AREA

UNIT 1. PLANET EARTH

SESSION 5. REPRESENTING THE EARTH’S AREA

Geographic Network

You have to Know…

Geographers represent geographical space by using maps. The Earth’s shape is almost spherical. This is why it is represented by a globe or by projections onto a plane. Any point on the Earth’s surface can be located with a map. We use parallels and meridians to do this.

Latitude and longitude lines form an imaginary grid over the Earth's surface. By combining longitude and latitude measurements, any location on Earth can be determined.

The units of measurement for geographic coordinates are degrees (°), minutes ('), and seconds ("). Like a circle, the Earth has 360 degrees. Each degree is divided into 60 minutes. Each turn is divided into 60 seconds.

Latitude and longitude coordinates also include cardinal directions: north or south of the equator for latitude, and east or west of the prime meridian for longitude.

·        Aditional information

Parallels are imaginary circles perpendicular to the axis of the Earth. They are parallel to each other. They measure 360 degrees.

The Equator is the largest parallel and it divides the earth into two hemispheres: North and South.

Parallels

Features

- They are parallel to each other.
- Their number is infinite.
- They have E-W direction.
- Parallels and meridians cut each other at a right angle.
- They form a circumference of 360 º.

Main parallels

Main parallels Source: Factormonster.com

In the northern hemisphere: Tropic of Cancer: 23 degrees 27 'N. Arctic Circle: 66 ° 33 'N In the southern hemisphere: Tropic of Capricorn: 23 º 27 'S. Antarctic Circle: 66 ° 33 'S

The meridians are imaginary maximum semicircles from the north pole to south pole. They measure 180 degrees.

The meridian of reference (0 degrees) is Greenwich. Its name comes from the astronomical observatory located near London.

Meridians

Features

Meridian of Greenwich

There are infinite meridians. Their direction is N-S. They have their maximum separation in Ecuador and converge at the poles. They cut the parallels at right angles. The arc of a parallel has a value of 180 degrees.

·         Vocabulary

·          

-          Network: a system or group of connected parts

-          Grid: a structure made from horizontal and vertical lines crossing each other to form squares

-          Flat suface: the outer or top part or layer of something.

-          Scale: the set of numbers, amounts, etc used to measure or compare the level of something

-          Range: a group of different things of the same general type

-          Measurement: the act or process of measuring

-          Degree: an amount or level of something

-          Features: a typical quality, or important part of something

-          Right angle: an angle of 90°

-          Converge: When lines, roads, or paths converge, they move towards the same point where they join or meet

·         Exercises:

·          

1.    What are the latitude and longitude lines used for?

2.    Put in a table the main features of parallels and meridians.

·         Investigator’s corner

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-          Why the reference meridian is called Greenwich meridian?