Packing the world for longest lines of sight

(tombh.co.uk)

58 points | by tombh 2 days ago

7 comments

  • dolmen 22 minutes ago
    Does the source dataset includes with enough precision human made buildings?

    Will it allow to determine the farthest point theorically visible from the top of the Eiffel Tower?

  • rendaw 1 hour ago
    I was recently looking into this for roguelike-like visibility calculations. The term I came across was "isovist" not "viewshed", but they seem identical? The former appears to be used a lot in architecture.

    Calculating a 2d isovist is (relatively) simple, for 3d it seems much more complex. Is this simplified by the fact that it's dealing with a height map?

  • greggsy 4 hours ago
    Related, there’s a Reddit post tracking the furthest photos of the Sydney skyline:

    https://www.reddit.com/r/sydney/comments/1lzke5t/the_actual_...

    Google Earth map: https://earth.google.com/web/@-32.84964163,149.89452785,590....

    • SpicyUme 1 hour ago
      There's a nearly 450 km photo of the Ecrins from the Pyrenees!

      https://beyondrange.wordpress.com/2016/08/03/pic-de-finestre...

      That's a cool thing to track, I've been surprised by the places I've seen the Seattle skyline reflected on the water near sundown. No crazy distances, but there's a small time period where it flashes into view.

  • lsy 1 hour ago
    I'm sure it's nearly an academic distinction, but:

    > Basically, for any given region, we find its highest point and assume that there is a perfectly placed sibling peak of the same height that is mutually visible.

    Shouldn't you always add 335km to the horizon distance to account for the possibility of Everest (i.e. a taller sibling peak) being on the other side of the horizon?

    • tennysont 51 minutes ago
      You're right, but all lines of sight are mutual, so we will notice this oversight when checking the other peak.

      This seems poorly explained, but I think the author was in a hurry to get to the main algorithm, and sped through the intro.

  • eszed 2 hours ago
    Since you asked about alternate packing solutions:

    https://news.ycombinator.com/item?id=43305920

    I don't know enough about the subject to have any useful suggestions, but I'd be interested in your take on how a project like yours would work differently if you were to choose a different solution.

  • cozzyd 3 hours ago
    If you consider atmospheric refraction it might be more complicated...
  • temptemptemp111 1 hour ago
    [dead]