Navigation Flashcards
What is the axial tilt of the earth?
23.5 Degrees
What are longitude lines?
Meridians of Longitude are lines that join True North and True South Poles
At what longitude is the Prime Meridian?
0 degrees longitude
How is longitude referenced?
East or West of the Prime Meridian up to 180 degrees. Therefore there is the Anti-Meridian opposite the Prime.
What are latitude lines?
Parallels of Latitude are lines that circle the earths surface at right angles to lines of longitude and are parallel to each other.
How is latitude referenced?
North or South from the equator, which exactly half way between the True North and True South Poles. Therefore the maximum value is 90 degrees.
How is a position on the earth reference using longitude and latitude?
By using degrees, minutes and seconds.
60 seconds in a minute and 60 minutes in a degree.
Rather than writing sections, it is also possible to write fractions of a minute.
How is a nautical mile defined?
An angle of one minute of latitude. (1/60th of a degree)
What is a great circle?
The shortest distance between two points on the earths surface. They cross meridiants of longitude at different angles.
What is a rhumb line?
Cross all meridians of longitude at the same angle
What is an isogonal?
Lines of equal magnetic variation
What is variation?
The difference in bearing between True North and Magnetic North
What is a sideral day?
The time taken for the earth to complete one rotation. Ie for one meridian to rotate 360 degrees in line with a fixed point in space.
23 Hours 56 minutes
How long is the mean day?
24 Hours
How long does it take for the earth to rotate 15 degrees?
1 hour.
15 degrees longitude = 1 hour
(360/24)
Will east or west be ahead or behind UTC?
East will be ahead
West will be behind
What is conformity on a map?
Where directions/bearings are accurate. Ideally latitudes and longitudes should cross each other at 90 degrees.
What is equivalence on a map?
When the scale of the map does not vary
What does a straight line on a lambert conformal conic projection represent?
Great Circle
What does a straight line on a mercator projection represent?
Rhumb Line
What is 1nm in miles?
1.15 miles
What is 1nm in km?
1.852km
What is 1nm in ft?
6080ft
What is 1m in ft?
3.28ft