Finding Locations on Earth

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Finding Locations on Earth
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Latitude

• A set of parallel circles that describe
  positions north and south of the equator
• These parallels run east-west, but are not to be
  confused with measuring easterly or westerly
  locations
• parallel - any circle that runs east and west
  around Earth and tat is parallel to the equator
  a line of latitude
• latitude - the angular distance north or south
  from the equator expressed in degrees

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What parallels mean..
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How to find latitude

• http//www.classzone.com/books/earth_science/terc/
  content/investigations/es0303/es0303page02.cfm?cha
  pter_noinvestigation

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Latitude

• Since lines of latitude are parallel, the
  distance between latitude lines is relatively the
  same around the world
• In actual distance, 1 latitude equals about 111
  km.

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Longitude

• East-west locations are established by using
  meridians.
• meridian - any semicircle that runs north and
  south around Earth from the geographic North Pole
  to the geographic South Pole a line of longitude
• Longitude - the angular distance east or west
  from the prime meridian expressed in degrees

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Longitude

• 0 Longitude is located at the prime meridian
  running through Greenwich, England
• The International Date Line is 180. It can be
  marked either E or W of the prime meridian

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Distance Between Meridians

• The distance covered by a degree of longitude
  depends on where the degree is measured. The
  distance measured by a degree of longitude
  decreases as you move from the equator toward the
  poles.

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• Since meridians converge at the poles, the
  distance between longitude lines is not constant
  around the globe.

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Great Circles

• They divide the globe into halves
• Are oftentimes flight paths because they are the
  shortest distance

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Great Circle Mapper

• http//gc.kls2.com/cgi-bin/gc?PATHNRT0D0ARANGE
  PATH-COLORredPATH-UNITSnmPATH-MINIMUMSPEED
  -GROUNDSPEED-UNITSktsRANGE-STYLEbestRANGE-CO
  LORnavyMAP-STYLE

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The Poles

• The areas on Earths surface just above where the
  poles of the imaginary magnet would be are called
  the geomagnetic poles.
• The geomagnetic poles and the geographic poles
  are located in different places.

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The Real North Pole
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Magnetic Declination

• The angle between the direction of the geographic
  pole and the direction in which the compass
  needle points is called magnetic declination.
• In the Northern Hemisphere, magnetic declination
  is measured in degrees east or west of the
  geographic North Pole.
• Because Earths magnetic field is constantly
  changing, the magnetic declinations of locations
  around the globe also change constantly.
• By using magnetic declination, a person can use a
  compass to determine geographic north for any
  place on Earth.

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Magnetic Declination

• True north (geomagnetic pole) what your compass
  is really pointing to

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East West Magnetic Declination