The measurement of longitude is important both to cartography and to provide safe ocean navigation.

After all you can see your destination - it's not like ocean navigation.

Historically, the most important practical application of these was to provide safe ocean navigation.

He was "the first advocate of the plans at present adopted by English and American naval architects in the construction of long vessels for ocean navigation.

Moreover, Pidgeon had no previous experience with ocean navigation, boat-building, or long-distance sailing.

At the time England enjoyed a monopoly over the ocean navigation to and from the United States.

Colonist records and contracts were stored here, along with written procedures for doing everything from ocean navigation by the stars to (4) sawing down a tree.

It's something like that early level of ocean navigation we're at in galactic space now.

You remember my talking about the early days of ocean navigation?

Early American mathematician remembered for his work on ocean navigation.