Maps and Charts Flashcards
Explain Orthomorphism/Conformality
Scale is correct in all directions and bearings are correctly represented
What is the standard parallel with regards to a Lambert Conical projection?
The point where the cone touches the surface of the reduced Earth
What is the constant of the cone/chart convergence factor on a Lambert Conical projection?
The amount of the circle remaining when the cone is unrolled.
How can the constant of the cone be calculated using the parallel of origin on a Lambert Conical projection?
Sin( Parallel of Origin ) = Constant of the Cone
Sin-1( Constant of the Cone ) = Parallel of Origin
On a Lambert Conical projection, the scale is __ at the standard parallels, ___ between them, and ___ outside of them.
correct, contracted, expanded
Great circles on a Lambert Conical are drawn as ___
straight lines, slightly concave to the parallel of origin
Rhumb lines on a Lambert Conical are drawn as ___
Curves concave to the nearer pole
On a Lambert Conical, the scale is correct at the ___, and the convergency is correct at the ___.
Standard Parallels, Parallel of Origin
On a Mercator projection, the scale varies with ___
The secant of latitude. Secant( Angle ) = 1 / Cos( Angle )
On a Mercator projection, great circles are plotted as ___ near the Equator, and as ___ away from the Equator
straight lines, curves concave to the Equator
On a Polar Stereographic projection, the parallel of origin is at the ___
Pole
On a Polar Stereographic projection, the scale ___ away from the pole
expands
On a Polar Stereographic projection, scale and convergency are correct at the __
pole
On a Polar Stereographic projection, great circles are slightly concave to the ___
pole
On a Polar Stereographic projection, convergency equals ___
change of longitude
High latitudes are those above __N/S
65
Polar tracks are those located in regions where the horizontal component of the Earth’s magnetic field are less than _ microtesla
6
If True North is East of Grid North, convergence is ___
Easterly
GH = TH _ W or _ E convergence
+, -
TH = GH _ W or _ E convergence
-, +
Variation West, Magnetic ___
Best
Grivation is the difference between ___ and ___ direction
Grid, Magnetic
Grivation is the sum of ___ and ___
variation and grid convergence
Grivation East, Magnetic ___
Least
Isogrivs join points of equal ___
grivation
Formula for conversion of scales on a Mercator projection
( Denominator x Cos( B ) ) / Cos( A )
Outline the way to quickly convert headings from Compass to True
< – + W –
C D M V T
Sum of C and D will equal M.
Always minus when going left (i.e negatives become positive)
Agonic lines are those which join points where ___
magnatic and true meridians are paralle
