Lighthouse Map

5 years ago (geodienst.github.io)

Would love to know why Norway has so many lighthouses / "blinking beacons". Wikipedia lists many [0], but not as many as shown.

[0] https://en.wikipedia.org/wiki/List_of_lighthouses_in_Norway

  • It's because Norway made a conscious decision to maintain its lighthouses.

    It's done to preserve the cultural legacy as the majority of lighthouses are obsolete.

    • Most lighthouses are cultural and historical icons, and they often faithfully reproduce the best technology of an era. Moreover, even if obsolete, most are wonderful architectural objects.

      I can only applaud Norway's decision to preserve its cultural legacy. Shame others aren't as proactive.

      2 replies →

  • It seems to include a lot of sector lights. Here is the nautical chart: https://norgeskart.no/#!?project=norgeskart&layers=1008

    • -That it does, I zoomed in on my local area (I can see five sector lights just from my office window on the northwestern coast of Norway - they're all over the place!) - all are present in the map.

      I love this map; would be even better if one could set opacity for the lights so that it is simpler to see the coastline details, though.

  • Maybe they just have provided more detailed data? Then again, Norway has a very rugged coast which is used a lot.

    • I was going to suggest it might have something to do with all of the fiddly bits that were a favorite of Slartibartfast.

First light I checked, and have verified in real life, is missing. Patos Island light on the Canadian border in the San Juan island group. Cute, but inaccurate.

https://keepersofthepatoslight.org/about-patos-island

Seems to be quite Europe focussed, but then again 'Dienst" is Dutch for "Service". It's a project of the university of Groningen [0]

[0] https://www.rug.nl/society-business/centre-for-information-t...

  • TIL that German and Dutch share the same word for "Service". :)

    • There's many such words, since the languages share a common root. I'm Dutch but work for a German company and the main language is English. If we can't find a word, typically stuff not core work related, it's often quickest to say the German or Dutch word.

Anyone have any idea why the dataset doesn't include any the lighthouses along the Oregon coast? It has ones in California and Washington, but nothing for Oregon. Strange.

  • A bunch of Oregon lighthouses exist in OSM but they don't have specific data about the signal sequence yet so they aren't displayed on this map. (an example of a sequence would be 0.5+(3.5) which means the light is shown for 0.5 seconds and eclipsed for 3.5 seconds)

    From the README: "it asks the Overpass API for all elements with an seamark:light:sequence attribute"

    If you run the query here you'll see that there's not any lights with sequence data in Oregon yet. https://overpass-turbo.eu/s/1fnZ

    If you run a new query you can find that there are plenty of lights on the OR coast with other attributes. (try searching for: "seamark:light:character=*" for instance)

    I looked at some US coast guard data and found that while most light houses have data on the colour, characteristic, and period, it's rarer to have sequence data. I think for most purposes, just knowing that there's a white light that flashes every 4 seconds is good enough. Knowing that the light flashes for 0.5 seconds is probably less needed (unless you're making a map visualization)

    If you really want to see the OR lighthouses you could find and add sequence data to lighthouses in OSM. Or you could fork this and write some code to visualize the lights that have some data (like colour and period) but not sequence, by making some assumptions/default values.

Is this at all accurate?

San Francisco has dots in random places. But, to me, the most obvious missing lighthouse is the Montauk Point Light.

Nice idea but could do with a key. Why are some bigger? What do the colours mean? What's the blinking about?

  • It is a very literal encoding: the colors are the actual colors of the lights (unless you uncheck the "Show real colors" checkbox), they flash in the same pattern as the actual lights, and the radius of the circles is proportional to the nominal visible range (but I think they are smaller than the actual range [1]).

    [1]: https://github.com/geodienst/lighthousemap/pull/9

Looks like this is a work in progress. All the nav markers on buoys seem to be in place for the SF Bay, but none on the coastline or in Oregon. But hey, looks like it's on GitHub for anyone to submit patches.

Very cool.

One thing I noticed on mobile - if you pan far enough in either direction such that the tiles end up wrapping / repeating, you lose all of the map markers.

I would make the point size dependent of the scale. When I zoom in I get huge balls. And I would make them not blink.

  • The size of the points shows the reported visible range, the colour and pattern of blinks represents how the light should appear. But this all depends upon the OSM data being entered correctly, and as https://github.com/geodienst/lighthousemap#readme notes:

    "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."