The (pun ahead) peak of this method imho is implemented in "PeakFinder", afaik uses a low res nation wide (switzerland) height map, after initial gps fix it downloads local high res height map, calculates peak contours based of current location AND height and overlays that grid including the peak names onto the camera feed using the gyro and compass.

It's quite easy to build accurate geo-related applications in Switzerland due to the excellent work of the government office "Swiss Topo" that maps every tree, every house, every road in the whole country. Trees in cities have metadata such as: year planted, type etc. :)

Johnny Harris, the map aficionado mentioned Swiss maps and Swiss Topo's dedication multiple times in his videos.

This thing is awesome. I'm curious about the algorithm used to calculate it. Given a spherical height map, I guess the naive way to solve it would be to basically cast a whole bunch of rays from your starting point and see what you hit, but I wonder if you could do something more clever.

I'm also curious about this note: "Because of refraction, the further away an object is, the higher it will appear." I kind of figured that, like a ship sailing towards the horizon, the distant thing would get shorter as it got further away. I wonder why they get higher instead. Something about big elevation differences?

This is real clunky from a browser. https://caltopo.com can do this from a map (right-click on the viewpoint, point-info, simulated view). The horizonator (https://github.com/dkogan/horizonator/) is a hackable implementation; has a FAST local gui, and can easily be extended to do other stuff.

Related, but does anyone know of an app or site that can tell you what you're facing when you're standing on a beach? As in, what country or part of the country - so if you were standing on a Croatian beach somewhere and pointed it east, you could find out what part of Italy you're looking at.

I've always thought it would be cool to stand on a coast of Malta and tell if I'm facing Libya, Israel, or Greece.

Very nice! I personally use PeakFinder on my phone. It can overlay peak names directly onto the camera image. I think it’s well worth the five bucks.

Reminds me of the app from the Swiss federal office of topology (swisstopo), which has the same functionality (albeit limited to Switzerland, of course): https://www.swisstopo.admin.ch/en/swisstopo-application

This webapp seems to be more useful though, thanks for sharing.

I thought that this looked familiar. I used it when setting up an ADSB receiver to show the expected "visible" range from my house.

This (as previously posted) is one of my few Favorite posts on HN. Half because of how awesome it is, and half because I can never remember what it’s called.

Tangentially, are there any good map websites out there that show me the elevation at a point I click on?

I've found a lot of providers lacking in this department, even if they clearly have height data for showing contours/3d views.

Interesting, but clearly ancient (refers to a Google Earth plugin, for instance).

Are there more modern equivalents? I'd love to have an Android app which told me what the things were I was looking at.

You hike to the top of a mountain or pull off at a scenic overlook. You see mountains in the distance. Which mountains are they? HeyWhatsThat will tell you, providing a 360° panoramic sketch labeled with the names of the peaks you're looking at. From almost anywhere in the world.

> At HeyWhatsThat -- Russia? we tell you where in Alaska you can see Russia.

Man. Remember when saying something like that was enough to disqualify you from the presidency?

Neat and utilitarian tool that I've used for a while.

I'm always disappointed that it's not open-source though. It would be really cool to be able to run the "viewshed" / etc. calculations locally, instead of having to wait for their server.

I've used the site for years.. I've always ignored the dropdown with a million entries, it's terrible UX.

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