Form Of The Earth Flashcards
The Earths Shape
Oblate Spheroid
Compression Ratio
1/298
EQ Radius
- 56nm
6377. 47km
Pole Radius
- 97nm
6356. 01km
1nm
1.852km
6080ft
1 degree latitude =
60nm
Distance from EQ to Pole
5400nm
Circumference of Earth
21600nm
40,003.2km
How many minutes in 1 degree
60
1 minute = 1nm
Where will 1nm be longest
At the poles and shortest at the EQ
Latitude
ANgular distance to a point measured in n/s from EQ
Longitude
From Greenwich (GMT/UTC) - 180 degrees east to west Ante-Meridian = opposite or reciprocal On EQ - 1 degree = 60nm but converges towards the poles (cos)
Small Circles
Parallels of latitude
Any circle with a different centre
Great Circles
Meridians of longitude (EQ)
Have the earths centre as the centre of their circle
Parallels of latitude and Meridians of longitude cross at
90 degrees to each other
Rhumb Line
A regularly curved line that cuts all meridians at the same angle
Always EQ side of great circle
Concave to nearer pole
Parallels of Latitude are also rhumb lines as they cut meridians at 90 degrees
Northern Vertex
The most northerly point
Southern Vertex
Most southerly point
Antipodal
Opposite locations
Crossing Points
Have a 90 degree change of longitude compared to the Northern/Southern Vertex
Both added together will = 180 degrees
Track Angle
The angle between the track and the meridian.
Measured clockwise from the meridian.
West Bound NV
270 - True
Westbound SV
270 + True
Eastbound NV
90 - T
Eastbound SV
90 + True
