1. Chapter 3: Models of Earth

2. Chapter 3.1

3. Modeling the Planet
Globes are the best models. However, they are not convenient.

4. Maps Maps are flat 2-dimensional representation of earth’s surface.
All maps distort Earth’s features.
Cartographer – map maker

5. Map Projections – help reduce distortion
Mercator
Projects the planet as if a large cylinder had been wrapped around it
Distorts the areas near the poles
Gnomonic Projection
Is made as if a cone of paper had been wrapped around Earth
Useful for mapping large mid latitude areas

6. Latitude and Longitude
Earth is divided into 4 hemispheres
Equator divides the north and south hemisphere
Prime Meridian (0°) and the 180° meridian divide the East and West hemisphere

7. Latitude lines or parallels circle the world from east to west.
Measured in degrees north or south of the equator
Equator 0°, North Pole 90°N, South Pole 90°S
180° between the Poles

8. Longitude
Lines that run north to south that give position East or West of the Prime Meridian 0°
Longitude lines can be numbered from 0° to 180° East or West
One degree is divided into 60 minutes which is divided into 60 sec

9. Map Scale – how a maps feature compare in size to the actual earth
Fractional 1/24, : 24,000
Graphically I—1—2—3—4—I miles
Verbal “one inch equals one mile”

10. Chapter 3.2

11. Mapmaking and Technology

12. How Cartographers (map makers) traditionally worked
Plane-table survey – climb to the area’s highest vantage point and draw a map of whatever features he saw.

13. How Technology has changed mapmaking
Photography – pictures from above
Radar – Side looking radar

14. Satellite Technology Landsat Imaging Radar
EOS – Earth Observing System

15. Computers
Use Satellite information to decode and make images out of the data they collect
Global Positioning System (GPS)
Allows people to determine their position, speed and time anywhere in the world at anytime in any weather
24 satellites that follow circular orbits above Earth
Geographic Information Systems (GIS)
Combines satellite, statistical survey and traditional land surveys to make more useful maps.