Mapping the Earth

1
Mapping the Earths Surface
2
Who Makes Maps?

• Cartographers! (mapmakers)
• Cartography
• Science of mapmaking
• Use imaginary grid (parallel lines and vertical
  lines) to map exact locations
• Equator is exactly halfway between N and S poles
• Separates the Earth into Northern and Southern
  hemispheres

3
Latitude

• Lines parallel to equator Latitude lines
• Latitude distance (in degrees) north or south of
  equator
• Equator is 0 latitude
• Poles are 90 latitude
• North of equator North
• South of equator South
• Each degree is 111 km on Earths surface

4
Longitude

• Lines are meridians
• Run north to south measures distances East and
  West
• Prime Meridian is 0 longitude
• Runs through Greenwich, England
• 0 to 180 East 0 to 180 West

5
Longitude, cont.

• Longitude lines are NOT parallel
• Large semicircles extending from North Pole to
  South Pole
• Meridian opposite of the prime meridian is the
  180 meridian
• AKA International Date Line

6

• Both Latitude and Longitude must be used to
  locate a place with coordinates

7
Time Zones/Calendar Dates

• 24 Time Zones on EarthWHY?
• 24 Hours in a day (24 hours to rotate on axis)
• Each zone represents a different hour
• When you travel through a time zone you gain or
  lose time
• Eventually you gain or lose a day!
• International Date Line (180 meridian) is
  transition line for calendar days

8
Time Zones
9
Time Zones

• There are six different time zones in the United
  States

10
Mercator Projections

• Map with parallel lines of latitude and longitude
• Causes areas of landmasses to be distorted
• Ex Greenland appears larger than it really is
• Shapes of landmasses are correct
• Used for navigation of ships

11
Conic Projections

• Made by projecting points and lines from a globe
  onto a cone
• Cone touches the globe at a particular line of
  latitude
• Little distortion along this line
• A lot of distortion near top/bottom
• Good for mapping small areas
• Road maps
• Weather maps

12
Gnomonic Projection

• Created by projecting points and lines from a
  globe onto a paper that touches the globe in one
  location
• Distort direction and distance between landmasses
• Useful to plot long distance air/sea trips

13
Topographic Maps

• Used to show changes in Earths elevation
• Use contour lines to show elevation
• Line that connects points of equal elevation
• Contour lines can never cross
• This would mean that one spot has two different
  elevations!
• Difference between adjacent contour lines is
  called a contour interval

14
Topographic Map
15
Topographic Maps, cont.

• Contour lines very close together indicate a hill
  or mountain
• Contour lines showing a depression (valley) have
  hachure marks
• Hachures are perpendicular to the contour line
• Hachures point toward the lower elevation

Depression Contour Lines
16
Map Legends and Scales

• A legend explains what the symbols on a map
  represent
• A map scale is the ratio between distance on the
  map and distance in real life

17
Remote Sensing

• Uses satellites that make use of the
  Electromagnetic Spectrum
• Detect different types of waves

18
Landsat Satellite

• Receives reflected wavelengths of energy emitted
  by surface of Earth
• Features at different temperatures reflect
  different wavelengths
• Images show up as different colors
• Used to study plate movement, earthquakes,
  pollution

19
Topex/Poseidon Satellite

• Uses radar to map features of the ocean, changes
  in tides, and ocean currents
• Topex stands for Topography experiment
• Signals are transmitted from Topex to oceans
  surface
• Receiving device picks up echo off ocean
• Calculate how long it takes for signal to get
  back to satellite
• Helps to identify features (underwater mountains,
  etc)

20
Topex/Poseidon Satellite
21
GPS

• Global Positioning System
• Radio-navigation system of 24 satellites
• Users can determine exact location on the Earth
• Several satellites can send signals to someone
  with a hand-held receiver
• Receiver calculates latitude and longitude
• Can also provide info on elevation, direction,
  and speed
• Used most often by ships and airplanes
• Also used to track wildlife, create maps, and
  detect earthquakes

22
Sea Beam

• Similar to Topex
• Used to map the ocean floor
• Located on a ship
• Uses sonar
• Sound wave is sent to ocean floor
• Wave bounces off sea floor and echo is recorded
  by ships receiver
• Distance is calculated using speed of sound and
  return time of the sound wave