This map is alive with the beauty of lighthouse signals

The unique light signatures of nautical beacons translate into hypnotic cartography.

This map is alive with the beauty of lighthouse signals

At night, the rims of the North Sea flicker and flash with a multitude of light signals to guide ships to safety.

Credit: Geodienst – Lights at Sea
  • Many of the world's 23,000 lighthouses feature a distinct combination of color, frequency, and range.
  • These unique light signatures help ships verify their positions and safeguard maritime traffic.
  • But they also translate into this map, visualizing the ingenuity and courage of lighthouse builders and keepers.

Land and sea are both shaded dark, so it's a bit hard at first to make out that this collection of merrily blinking lights is actually a map. Once the coastal contours pop, though, all becomes clear: these are lighthouses!

At night, the Eastern Mediterranean is awash with lighthouse signals. Credit: Geodienst – Lights at Sea

The Age of Big Data

The map not only shows where they are, but how they are: static or blinking in various colors with the size of the circles corresponding to the range of their lights.

Up until the 20th century, a map of lighthouses would have been a subdued affair: just a string of dots strung along lines of coast. But this is the 21st century! We're in the Age of Big Data, ruled by the clever boffins who know how to stitch one dataset to another. Zap it with electricity and presto: it's alive!

That's what the folks did over at Geodienst, the spatial expertise center of the University of Groningen (Netherlands). Back in 2018, student/assistant Jelmer van der Linde (currently with the University of Edinburgh) came across OpenSeaMap, an open-source resource for nautical information similar to its more famous landlubber cousin, OpenStreetMap.

OpenSeaMap contained a database with detailed information on nautical beacons and lighthouses, which included not just their location, but also the frequency, range, and even the color of their signals. Would it be possible to visualize all those data points on a map? Yes, it would!

Norway's craggy coastline requires lots of light. Not that much blinking going on, though. Credit: Geodienst – Lights at Sea

The result is this riot of a map. It's important that ships don't mistake one lighthouse for another. That's why they come in various colors and their lights flicker with a distinct frequency. Norway in particular is lit up with beacons and lighthouses, as its fjord-indented coast warrants. And the rest of Europe is well provided with nautical warning lights.

However, while the map is reminiscent of other global traffic trackers for flights (like Flightradar24 or FlightAware) or shipping (such as VesselFinder or MarineTraffic), it is neither live nor global. The flickering lights aren't a real-time report; they merely repeat the code in the original database. And that database is incomplete.

Zoom out, and the map gets a bit too dark. According to the Lighthouse Directory, there are at least 23,000 lighthouses in the world. And even though the United States has more lighthouses than any other nation700 by some counts – the map only shows a handful of lights in North America.

Like its parent, the lighthouse map is open source too, so if anyone out there is capable of filling in the gaps, they can. Lighthouse enthusiasts, get to it!

Not one yet yourself? Below are 10 lighthouse facts to help you come over to the light side.

Now you see them, now you don't. Credit: Geodienst – Lights at Sea

Trapped in a giant phallus and other true facts about lighthouses

  1. The world's smallest lighthouse is the North Queensferry Light Tower, near the Forth Bridge in Scotland. A mere 16 feet (5 m) tall, it was built in 1817 by Robert Stevenson, famous builder of lighthouses, as was his son Thomas, who was the father of the famous novelist Robert Louis Stevenson.
  2. Reaching a height of 436 ft (133 m), Jeddah Light in Saudi Arabia is the world's tallest lighthouse.
  3. The 2019 movie The Lighthouse, starring Willem Dafoe and Robert Pattinson, was based on a true incident, known as the Smalls Lighthouse Tragedy. In 1801, a storm trapped two Welsh lighthouse keepers, both named Thomas, in their lighthouse. One died, the other went mad. Asked to summarize his film, writer/director Robert Eggers said, "Nothing good can happen when two men are trapped alone in a giant phallus."
  4. From its inauguration in 1886 until 1901, the Statue of Liberty also served as a lighthouse. Its nine electric arc lamps, located in the torch, could be seen 24 miles out to sea.
  5. All U.S. lighthouses are now automated – save for Boston Light, the oldest continually used lighthouse in the country. For historical reasons, Congress has decided it shall remain staffed year-round.
  6. Hook Lighthouse, on Hook Head in Ireland's County Wexford, claims to be the world's oldest lighthouse still in use. It was first built by a medieval lord in the early decades of the 13th century.
  7. The Tower of Hercules in La Coruña, Spain has a slightly better claim. It was built by the Romans in the 1st century AD and still functions as a lighthouse.
  8. Stannard Rock Lighthouse is also known as "the loneliest place in the world." It is located in Lake Superior, Michigan. At 24 miles (39 km) from shore, it is the most remote lighthouse in the U.S. and one of the most remote in the world. It opened in 1883 and was staffed for parts of the year until 1962.
  9. A lighthouse on Märket is the reason for the weird border on the island, divided between Sweden and Finland. In 1885, the Finns built a lighthouse on the highest part of the island – on the Swedish half. Thanks to a complicated land swap, the lighthouse is back on the Finnish side.
  10. In the United States, August 7 is National Lighthouse Day.

Robert Pattinson (left) and Willem Dafoe in The Lighthouse.Credit: © 2019 A24 Films, via IMDB

Strange Maps #1082

Many thanks to Toon Wassenberg for sending in this map. Got a strange map? Let me know at

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