Chapter 3 Section 1Modeling the Planet

Objectives:-Explain how maps are models of Earth-Compare and contrast three types of map projections-Use latitude and longitude to describe a location on Earth

Maps

• A flat two-dimensional representation of Earth’s surface

• Those who make maps are called cartographers

Mercator Projection

• Depicts Earth as if a large cylinder of paper had been wrapped around the planet

Gnomonic (planar) Projection

• A gnomonic map projection displays all great circles as straight lines. Thus the shortest route between two locations in reality corresponds to that on the map.

Polyconic Projection

• A conic projection of a map having distances between meridians equal to those distances on a globe

• Good for representing large land masses

Hemispheres

• Earth divided into halvesNorthern and Southern hemispheres are

separated by the equator

Eastern and Western are divided by the prime meridian

Latitude

• These lines circle the world from east to west parallel to the equator. All measurements are in relation to the equator

– Arctic Circle (600 North) – Tropic of Cancer (23.50 North)– Equator (00)– Tropic of Capricorn (23.50 South)– Antarctic Circle (600 South)

Longitude

• These lines circle the world from north to south. Measured east or west of the prime meridian

• Prime Meridian (00)• International Date Line (180 0)– United States lies between 650 and 1250 west

longitude.

Map Scales

• A ratio relating map size to earth size– For example: 1inch:1mile• In this case 1 inch on a map equals 1 mile on earth

Map Scale: