Australian Hydrographic Office
Includes notices to mariners, copyright and licensing details, and general information about hydrography.
Degree Confluence Project
Aims to visit each of the latitude and longitude integer degree intersections in the world, and to take at least one picture at each location.
Galileo Global Navigational Satellite System
European Space Agency project to launch a series of satellites in order to create a global navigation and positioning system for civil purposes.
John Harrison and the Longitude Problem
The story behind the manufacture of John Harrison's marine timekeepers, which allowed early sailors to establish their longitude. Presented by the Royal Observatory in Greenwich.
NOVA: Lost at Sea - The Search for Longitude
Companion to the PBS special about the quest for a method of determining a seafaring ship's longitude. Learn why ocean navigation depends on knowing what time it is.
U.S. Coast Guard Navigation Center
Provides worldwide users with reliable navigation signals, timely operational status, general navigation, and other information.