Projections: DGCA Air Navigation questions

Every projection gives something up to flatten the Earth. Mercator keeps rhumb lines straight, Lambert conformal conic keeps great circles nearly straight in mid latitudes, and polar stereographic serves the high latitudes.

Its 52 questions mix chart properties with scale working, from map length to earth distance and from one Mercator latitude to another. Exam sessions have set 13 of these scale and property items.

On a Mercator chart scale grows with the secant of latitude, so a fixed length covers fewer nautical miles away from the equator. Lambert scale is correct on the two standard parallels, but convergence is correct at the parallel of origin. Put both lengths in one unit before writing a scale ratio.