Always use which scale to measure distance on a chart?

The correct choice for measuring distance on a chart is latitude. On nautical charts, the latitude lines run parallel to the equator and are critical for measuring distances from north to south. These lines are spaced evenly, making it straightforward to determine distances based on the degree of latitude. One degree of latitude is approximately equal to 60 nautical miles, which is a standard unit of measurement in maritime navigation.

Using latitude to measure distances helps mariners understand how far they are traveling when moving along a north-south axis, which is essential for effective navigation. It is also worth noting that while longitude can also be used to measure distances, the varying degrees of distance between lines of longitude, depending on their proximity to the equator, makes latitude a more consistent choice.

Altitude and depth focus on vertical measurements, which are not applicable for measuring distance on a chart, emphasizing the importance of understanding how to properly use latitude for accurate navigational purposes.