Maps And Charts Flashcards
(49 cards)
What is a planar projection (plane)
Gnomonic
Polar stereographic production
Basically a piece of paper held up to the side of globe
What is a cylindrical projection
Wrap a piece of paper round the equator
= cylinder around globe
Mercator projection
Direct Mercator projection (when paper wrapped round equator)
Transverse Mercator = wrapper round a meridian = good for countries with lots of N/S and little E/W
What are the ideal properties of a chart
Distances should be shown at constant scale
Angles should be correctly shown
Also
Show a great circle as a straight line
Or
Show a thumb line as a straight line
Capable of producing chart anywhere in the world
Produce charts that line up when adjacent sections are fitted together
What is conformal / orthomorphic chart
Must be :
Scale is same in all directions
Projection must provide a right angle graticule
If orthomorphic = Angeles correctly represented
What is GRID MORA
Min off route altitude
Safety altitude
What happens to scale on a direct Mercator chart
As moving away from equator scale expands north south / east west
Not constant scale
Expands with the secant of 1/cos
Where is convergency correct on a direct Mercator chart
At equator
How does great circles get represented on a a direct Mercator chart
Concave to the parallel or origin
Where is scale perfect
Where scale is 99% correct
= 8°N / 8°S
= 480nm north and south
On a lamberts conformal projection what are parallels or latitude
Arcs of concentric circles
On a lamberts conformal projection what are meridians
Straight lines
Converting at the pole
Convergency is irrespective of latitude
On a simple conic convergence chart where does chart convergency equal earth convergency
Parallel of origin
What is a rhumb line on a simple conic chart
Curved line
Concave to the nearest pole
What is chart convergency = on a simple conic chart
Chlong x sin parallel of origin
What is the constant of the cone
Constant of the come = n = sin parallel origin = convergency factor
When is scale perfect on a simple conic lamberts projection
At the parallel of origin
What is a lamberts conformal projection
2 standard parallels
1 parallel or origin in between what
What is the constant cone of a lamberts conformal projection
Sin parallel of origin
Where is scale perfect on a lamberts conformal projection
Standard parallel
What is the scale perfection of the parallel or origin on the lamberts conformal projection
Max deviation of less than 1%
On a lamberts conformal projection what are rhumb lines
Concave to the nearest pole
What is the only true straight line on a lamberts conformal projection
Meridians
On a lamberts conformal projection where is chart convergency = earth convergency
Parallel or origin
North of parallel of origin = chart < earth
South of parallel of origin = chart > earth
Is there convergency for VOR on lamberts conformal projection
Nope
