NAVIGATION TRAINING

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NAVIGATION TRAINING Section 2 Terrestrial
Coordinate System
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Table of Contents

• Section 1 Types of Navigation
• Section 2 Terrestial Coordinates
• Section 3 Charts
• Section 4 Compass
• Section 5 Nautical Publications
• Section 6 Navigational Aids

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Table of Contents

• Section 7 Buoyage
• Section 8 Position Lines and Fixes
• Section 9 Tides
• Section 10 Currents
• Section 11 Weather

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Terrestrial Coordinate System
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Earth A not-so-perfect Sphere
For navigational purposes, its considered a
true sphere with a circumference of 21,600 NM
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Terrestrial Coordinate System

• Great Circle The intersection of a plane
  passing through two points on the surface of
  the earth and the center of the earth.

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Terrestrial Coordinate System

• Examples are The Equator, Meridians of
  Longitude, the Prime Meridian being through
  Greenwich, near London, United Kingdom.

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Equator

• The great circle formed by passing a plane
  perpendicular to the earths axis halfway between
  its poles.

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Equator

• The equator divides the earth into northern and
  southern hemispheres.
• One of the two great circles from which all
  locations on the earths surface are referenced.

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Terrestrial Coordinate System

• Small Circle A circle formed from the
  intersection of a plane not passing through the
  center of the earth.
• Examples are Parallels of Latitude

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Measurement of Arc

• Positions in relationship to Earths Coordinates
  system are expressed in
• PRONOUNCED SYMBOL
• Degrees ()
• Minutes ()
• Seconds ()

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Latitude

• Latitude - angular distance north or south
  between the equator and the parallel of a point.
  Latitude is measured in degrees of arc from
  0-90 either north or south of the equator.
• Latitude is measured along a meridian.

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Latitude

• Latitude is always expressed using 2 digits, e.g
  49º
• Always given first when giving a position
• The length of 1 degree of latitude is always 60NM

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Parallels of Latitude
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Prime Meridian

• The meridian that passes through the original
  position of the Royal Greenwich Observatory near
  London, England.
• Constitutes the second reference line for the
  terrestrial coordinate system.

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Prime Meridian

• All other meridians are referenced to the prime
  meridian it divides the earth into the eastern
  and western hemispheres.

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Longitude

• Longitude - angular distance E/W between the
  prime meridian and the meridian of a point.
• Longitude is measured in degrees of arc from 0 to
  180 degrees east or west of the prime meridian.
• Longitude is measured along parallels of latitude

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Longitude

• Longitude is always expressed using 3 digits, e.g
  123º.
• One degree of long does not equal 60 NM unless
  measured along the equator.
• Always given after Latitude when giving a
  position.

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Lines of Longitude
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