That´s crazy! Lighthouse map visualizes lighthouses with their range, color, and flash patterns.
It asks the Overpass API for all elements with an
seamark:light:sequenceorseamark:light:1:sequenceattribute, decodes these, and displays them as coloured circles on the map using Leaflet. It also tries to take theseamark:light:rangeandseamark:light:colourinto account.
It´s provided by Geodienst, which belongs to the Center of Information Technology of the University of Groningen.