Navigation General · Chart Datums & Projections
On a Mercator chart, which of the following statements is TRUE?
- AGreat circles appear as straight lines
- BRhumb lines appear as straight lines✓ Correct
- CThe scale is constant in all directions at all latitudes
- DMeridians converge toward the poles as on the earth
Explanation
On a Mercator projection, meridians are parallel vertical lines and parallels are horizontal lines, which means a rhumb line (constant compass heading) plots as a straight line. Great circles, by contrast, curve away from the equator. The scale increases with latitude, so it is NOT constant everywhere.
Authority: Bowditch (Pub. 9), Ch. 2
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