How does the navigator use basic latitude and longitude?

• A. To measure ship speed.
• B. To determine positions on a map and chart.
• C. To determine wind direction.
• D. To calculate distance to port.

Answer: (C)

Latitude and longitude provide a fixed grid that lets a navigator pinpoint exact locations on charts. Each place on Earth has a unique latitude (north–south position) and longitude (east–west position). By determining your current latitude and longitude, you place your vessel on the chart, determine your position, and plot a course to a destination. From there you can compute how far you are from a port or waypoint and steer along the desired route. Wind direction comes from weather observations and instruments, not from the coordinates themselves, and speed is measured with a log or speed instrument rather than derived from lat/long. Distances to ports are meaningful once you know both your position and the port’s coordinates.