Re: Tell us about life before GPS systems?
In The Beginning, Man stayed close to the coast. After that a Sextant was invented, which used the angle of the sun to determine Latitude. Columbus had a crude Sextant. He also had a compass. he just did not know what was out there, or how far land was. His voyage was about a month, which is a lot further than anyone had gone before.
The next big step was the invention of the accurate clock. Longitude was determined by taking speed readings at particular intervals. The readings were done by counting the knots in a line, that went thru your hands in a given time(hence Knots is a term for speed in nautical miles). Longitude was determined by averaging your speed over the total time of your voyage. All of this was considered "Dead Reckoning", where the first word was what you were if you were inaccurate.
This was used until LORAN was invented. LORAN helped you find lat/long, near the coasts and it's accuracy with charts, dead reckoning and a compass was pretty good. You sail coastally using LORAN, set a best guess course across the ocean using clocks, compasses and sextants, and figure our where you were exactly via LORAN or shoreline features, when you got close.
Now GPS is available anywhere in the world to show your position to 3 meters.
J/K
