I did not create this code, the original source is here and the map here.
Like many others, I learnt about this beautiful gem of data visualisation thanks to this viral tweet. I love it! This is such a great example of what can be accomplished with OpenStreetMap and crowdsourced data!
But I was equally disappointed as many others to see that the data hadn't been updated in 3 years.
So I dug in the code and found the Overpass query to fetch up-to-date data. And while I was at it, I added a Github Action to keep it updated. It runs every day at 00:15 CET for now, and I might make it update less often later to use even less energy.
This map shows all the blinking beacons from OpenStreetMap.
More specifically, it asks the Overpass API for all elements with an seamark:light:sequence attribute, decodes these, and displays them as coloured circles on the map using Leaflet. It also tries to take the seamark:light:range and seamark:light:colour into account.
The current version uses an extracted dataset, but the code allows for directly querying the Overpass API. However, since a query like the one used here can take multiple minutes to complete it is not very useful do always do live queries.
The leaflet.indexedfeaturelayer.js file contains an extension on Leaflet's GeoJSON layer that only add layers/features to the map that are (or are about to be) visible. It uses a spatial index to quickly query which features can be removed from the DOM, increasing performance.
leaflet.light.js contains my best guess on how a light sequence will look based on these descriptions. However, it might be inaccurate, and it tries to do its best with the sometimes not entirely consistent data from OSM.
This map is made by the Geodienst because it was a fun idea we wanted to try out. Feel free to fork this map and make your own visualisation of OSM data, or contribute improvements back to us.