Theory Flashcards
earth shape
The actual shape of the earth is an oblate spheroid.
is called geoid
measure
compression of the earth is 0.3% around 1/300
earth diameter at the equator is 23 NM or 43 km more than in the pole
WGS 84
it the gps/american reference of the world 1984.
ICAO adapted als the WGS 84 as world standard
Poles
extremites of the axis about which earth spins
inclinated aboud sun orbit of 23.5°
cardinal point
N
E
W
O
quadrantal
NW
NE
SE
SW
sexagesimal
360 angle
Position referece cystem
define position accurentely and unambigousy on etarh sfc
Great circle
is the shorted distance between 2 point
so is the shorter arc between 2 point .
2 point in eath sfc will be will be join only from 1 circle unless they are to the opposite side
example of freat circle
equator
meridian
are semi great circle
small circle
is a cìrcul where the radius and the centre is not the earth center -> parallel
max difference geodetic and geocentri
is at 45° N/S about 11.6°’ of arc
special parallel
artic circle 66.5 ° N
antartic 66.5° S
Cancer 23.5° N
Capricorn 23.5° S
Vertex
are the Northest or southest point of a great circle, when you are in the vortex you can only move left or right
crossing point
is a great circle that pass from the equator
rhumb line
is a regulary curved line on the eart surface witch cut the meridian at the same angle
special rhumb line/ equator
equator and meridians with antimeridian they are rhumb line and great circle
measure
1 km= 3280 ft 1 m = 3.28 ft Satus mile = 5280 ft ICAO definition of NM is 1852 m NM= 6080 feat
nautical miles
nautical miles at the equator is shorter 6048
NM at the poles is longer 6108
becuase the definition is that a NM is lenght of an arc in 1 great circle with an angle of 1 minute
