7 Navigation Theory Flashcards
The Earth rotates in a(n) _________ direction when looking onto the N.Pole
Anti-Clockwise
Latitude lines are ________ to the EQUATOR
PARALLEL
Longitude lines are ________ to the EQUATOR
PERPENDICULAR
The EQUATOR is a line of L___tude
LATITUDE
The Greenwich MERIDIAN is a line of L___tude
LONGITUDE
Lat and Long is denoted in ___es, _____s and ______s
DEGREES
MINUTES
SECONDS
What is a GREAT CIRCLE?
- A circle on the surface of a sphere who’s plane passes through the centre of the Earth.
- The shortest distance between two points on the surface of a sphere.
The Equator is a GREAT CIRCLE
What is a SMALL CIRCLE?
- A circle on the surface of a sphere who’s plane DOES NOT pass through the centre of the Earth.
- All circles (other than GREAT CIRCLES) are small circles.
MERIDIANS are aligned /
MERIDIAN - N/S
PARALLELS OF LATITUDE are aligned /
PARALLELS OF LATITUDE - E/W
What is a RHUMB LINE?
A line on the Earths surface that crosses MERIDANS at a constant angle.
Describe CONVERGENCE
As MERIDIANS move away from the EQUATOR they are no longer parallel and distance between them will reduce.
Lines of L___tude are ONLY parallel at the EQUATOR
LONGITUDE
1 nm is equivalent to _.__ statute miles, or _.__ km
1 nm = 1.15 statute miles
1 nm = 1.85 km
Measuring angles on the Earth is done with the ________ system
SEXAGESIMAL system
List the units of measurement in the SEXAGESIMAL system
DEGREES
MINUTES
SECONDS
A CIRCLE is divided into ___ degrees.
1 circle = 360 degrees
A degree is divided into __ minutes.
1 deg = 60 minutes
A minute is divided into __ seconds.
1 min = 60 seconds
1 nm equates to approx. _ minute of latitude
1 minute
60 nm equates to approx. _ degree(s) of latitude
1 degree
Nautical miles are an ANGULAR/DISTANCE measurement? (Choose one)
ANGULAR
Taken from the centre of the earth.
1 nm on the surface of the Earth equals 1 nm for an aircraft or a satellite in space.
Name the 3 standard units for speed.
kt - Knots
mph - Miles per hour
kph - Kilometres per hour
What are the advantages of using True North over Magnetic?
- Does not change with time
- Basis of most maps and charts
TRUE or FALSE?
Mag North and True North are in the same place?
FALSE
Converting true track to mag direction
Variation East, Magnetic _____
Variation West, Magnetic _____
Variation East, Magnetic LEAST
Variation West, Magnetic BEST
Determine Mag Track
True track = 130
Variation = 15E
Variation EAST, Magnetic LEAST
True - Var = Mag
130(T) - 15E = 115(M)
Determine Mag Track
True track = 060
Variation = 15W
Variation WEST, Magnetic BEST
True + Var = Mag
060(T) + 15W = 075(M)
Determine Mag Track
True track = 285
Variation = 5E
Variation EAST, Magnetic LEAST
True - Var = Mag
285(T) - 5E = 280(M)
Determine Mag Track
True track = 220
Variation = 10W
Variation WEST, Magnetic BEST
True + Var = Mag
220(T) + 10W = 230(M)
Beacons use MAG or TRUE bearings?
MAGNETIC
With respect to magnetic fields. What are isogonals?
ISOGONALS are lines of equal magnetic variation.
What is a GEOID?
The zero surface of the Earth defined by the deviation and variation of the Earth’s gravity.
What is a SPHEROID/ELLIPSOID?
A smooth representation of the Earth’s oblate spheroidal shape.
What is a SPHERE?
Come on. You know this one!
List the 3 different models that can be used to model the Earth’s shape
GEOID
SPHEROID/ELLIPSOID
SPHERE
Name the 2 types of Map Projections
Perspective
Non-Perspective
List the 3 types of PERSPECTIVE projection
- AZIMUTHAL
- CYLINDRICAL
- CONICAL
Due to distortion of a the Earth’s surface on charts, the scale can ____ be constant over the entire projection.
NEVER
To overcome the impossibility of a constant scale on map projections. We commonly use a _______ scale.
GRADUATED scale
Charts that represent bearings accurately are known as ________ Projections.
CONFROMAL Projections
PERSPECTIVE projections are also known as as ________ Projections.
TRUE (geometric) projections
NON-PERSPECTIVE projections are also known as as ________ Projections.
MATHEMATICAL projections
Moving LATERALLY or TRANSVERSALLY refers to movement in the - direction.
E-W direction