Determining Location

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Determining Location
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The Orange Skin Analogy

• The ideal map does NOT exist impossible to make
  a sphere into something flat
• So we try a few different angles depending on
  the need
• Mercator map
• Robinson map
• Conic map
• Gnomonic map

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Mercator Map

• Most distortion _at_ higher latitudes
• Good for compass work

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Robinson Map

• Most common
• Distortions around the edges

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Conic Map

• Good for mapping small areas
• Used to make road weather maps

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Gnomonic Map

• Accurate only at point of contact
• Used for sailors and air travel navigation
• Maps Great Circles!

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Global Grid

• Latitude
• Parallels distance North or South of the
  equator, measured in degrees.
• 1 degree of latitude 1/360th of the Earths
  circumference
• 25,000 miles 70 MILES
• 360
• minute 1/60th of a degree 1 mile
• second 1/60th of a minute .017 mile
• 0o latitude Equator
• 0o to 90o

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• 410 13 27 N

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N
S
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Global Grid

• Longitude
• Meridians distance East or West of the prime
  meridian, measured in degrees.
• 0o longitude Prime Meridian
  goes through Greenwich, England
• 0o to 180o

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E
W
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Great Circles

• Any plane that divides the globe in half
• Why do we use them? It show the shortest
  distance between two points
• Examples of famous great circles
• Equator
• Prime meridian
• Actually, ALL meridians
• Diagonal meridians too

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Magnetic

• Earths core is made of iron and nickel
• and it is spinning over 1000 mph. This creates
  a magnetic field around the earth

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Magnetic Declination
Geographic north
Magnetic north
magnetic declination difference between the
geographic and the magnetic north
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