01 - Navigation Principles

Question 1

Latitude

Answer 1

Expressed in 2 digits

• Angular distance North or South from the equator (0^º-90º)

Question 2

Longitude

Answer 2

Expressed in 3 digits

• Angular distance East or West from the Prime Meridian (0º-180º)

Question 3

Great Circle

Answer 3

Circle formed on the surface of the earth that passes trhough the center of the earth.

Question 4

Small Circle

Answer 4

Any circle on the surface of the earth not passing through the center of the earth

Question 5

Great Circle Route

Answer 5

Shortest distance between two points (follows a great circle)

• Not practical because it would require constant course changes

Question 6

Rhumb Line

Answer 6

A line that starts at point A and ends at point B

• Helps establish a true heading without constant change
• Longer route

Question 7

Composite Track

Answer 7

Combines Great Circle Route and Rhumb Line to utilize waypoints to maximize time and distance.

Question 8

Advantages of Mercator Projections

Answer 8

(Most commonly used chart)

• Rhumb lines, Meridians and parallels are represented by straight lines
• Meridians and parallels are perpendicular to each other, simplifying plotting projections

Question 9

Disadvantages of Mercator Projections

Answer 9

• High distortion in extreme latitudes (~60º)
• Great-Circle distances and directions are not readily determinate

Question 10

Types of Projections

Answer 10

1. Plane
2. Cylindrical
3. Conic

Question 11

Nautical Chart Agencies

Answer 11

1. National Ocean Service Corps (NOS)
2. Army Corp of Engineers
3. National Geospatial Intelligence Agency