Fundamentals of Marine Navigation

Navigation is the process of directing a craft safely from one point to another. The discipline encompasses dead reckoning, piloting, celestial, and electronic navigation, all sharing one coordinate framework.

Positions mean nothing without a datum. Geodesy models the Earth as an ellipsoid approximating the geoid, and charts are referenced to a horizontal datum that may differ from the GNSS datum by hundreds of metres.

A chart is a projection of the curved Earth onto a plane. Each projection distorts something; the navigator must know what is preserved and what is not.

Charts alone are insufficient. The publication library gives sailing information, light details, radio services, and the corrections that keep charts trustworthy.