How warships navigated without electronic aids

Did navies need sources such as National Geographic to find places, or could they navigate using their own charts and observations?

They used their own charts, dead reckoning, and observations of the sun and stars. Those skills also remained useful when GPS was spoofed or electronic navigation equipment failed.

A ship could estimate its track from course, speed, and propeller revolutions, then correct that estimate with observations of the sun and stars. Trained navigators used sextants and official hydrographic charts rather than public magazines or illuminated coastal landmarks. The Royal Navy preserved paper-chart and celestial-navigation requirements even as digital systems became dominant. GPS spoofing has since shown why a crew must still be able to recover position and continue safely after losing its electronic navigation picture.