How does lighthouses works, why is it so important?
In: Technology
Before GPS was invented, ships often navigated using maps with landmarks if they were near the coast: If you see two or more landmarks with a known location, you can triangulate the exact position of the ship by measuring the angle between the two. Their color and blinking pattern can be used to identify them: Lighthouse A might blink two times and have two stripes, lighthouse B blinks three times and has three stripes.
In addition to just signalling their location, lighthouses also often shine different colors and patterns in different directions, so you don’t need to whip out a compass to measure the angle between two lighthouses. So a map will show you exactly in which sectors the lighthouse signals which color, and multiple overlapping sectors mark safe and dangerous waters.
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