Directions, Latitude & Longitude

Direction and Cardinal Headings

• Cardinal directions: North, East, West, South; abbreviations are capital letters N, E, W, S.

Geographic North vs Magnetic North

• Geographic North: northernmost point on Earth along its axis.

• Magnetic North: northern end of Earth's magnetosphere; compass needles point here.

• It lies $960\ \mathrm{km}$ SE of true north.

Secondary Headings

• Intercardinal (secondary) directions: Northeast (NE), Northwest (NW), Southeast (SE), Southwest (SW).

Tertiary Headings

• Combinations of cardinal + secondary directions:

  • North-northwest, North-northeast, East-northeast, East-southeast,

  • West-northwest, West-southwest, South-southwest, South-southeast.

Compass Rose

• A figure on a map/chart displaying the orientation of the cardinal headings.

Latitude

• The globe is divided into the Northern Hemisphere and Southern Hemisphere.

• The Equator is the center line for lines of latitude.

• Latitudes are measured and named in degrees north or south of the equator.

Lines of Latitude (Parallels)

• Lines of latitude are parallels; they never intersect.

• They are $111\ \mathrm{km}$ apart.

Special Parallels (Latitude)

• Equator: $0^\circ$

• Tropic of Cancer: $23.5^\circ$ N

• Tropic of Capricorn: $23.5^\circ$ S

• Arctic Circle: $66.5^\circ$ N

• Antarctic Circle: $66.5^\circ$ S

• North Pole: $90^\circ$ N

• South Pole: $90^\circ$ S

Longitude

• The globe is divided into Eastern Hemisphere and Western Hemisphere.

• The Prime Meridian is the starting point for lines of longitude.

• Longitudes are measured and named in degrees East or West of the Prime Meridian.

Meridians

• All lines of longitude converge at the North and South Poles.

• Longitudes are also called Meridians or Great Circles.

• At the equator, lines of longitude are $111\ \mathrm{km}$ apart.

International Date Line

• Located at $180^\circ$ longitude; farthest you can be from the Prime Meridian.

Coordinates (Grid System)

• Latitude is given first and includes a cardinal direction (north or south).

  • Example: $36^\circ 42'\ \mathrm{N}$

• Longitude is given second and includes a cardinal direction (east or west).

  • Example: $81^\circ 58'\ \mathrm{W}$

• Combined coordinates: $36^\circ 42'\ \mathrm{N},\ 81^\circ 58'\ \mathrm{W}$ *The ‘ mark behind the 42 and 58 means (Minutes)

Quick Reference Points

• Intersections and naming:

  • Cardinal: N, E, S, W

  • Intercardinal: NE, NW, SE, SW

  • Tertiary: North-northwest, North-northeast, etc.

• Key parallels/meridians: 0°, 90°, 180°, 66.5°, 23.5°,

• Primary reference: Prime Meridian (0° longitude) and International Date Line (±180°).