Very little of anything actually goes on in Greenland. It has a population of less than 57,000 and a GDP of less than $5B. The US maintains significant military presence, including airbases, missile launch and intercept capabilities, and ensures the US controls the North Atlantic, instead of Russia.
I don't think it's really down to super-tight security as such, rather that there's no reason to release the data publically.
Ships and airplanes broadcast data because it's useful for collision avoidance and tracking. The international maritime and aerospace system is far too complicated and large that you could ever build a private network of every ship or plane operator sharing encrypted data, or that one company could set up receivers for the tracking data worldwide. A closed system wouldn't work.
Rail is both physically and legally a finite closed space. The network operator knows definitively where every train in their network is because they have sensors in the tracks. The network is responsible for preventing collisions, not the individual trains. They have contracts with every company which operates on their tracks and if these need their internal data they can get it. So there's simply no good reason why trains should be publically broadcasting their information, or why network operators would want to expose all their internal data.
And against the no positives there are negative sides - apart from a couple of famous cases I've not heard of it in Europe, but stealing from cargo trains seems to be big business in the US: https://www.latimes.com/california/story/2022-11-17/los-ange...
In the UK the open tracking data also brought complaints from freight companies who feared competitors would use it to analyse their movements, figure out which traffic flows were the most profitable and use it for commercial advantage.
Turn on the `Vessel presence` layer, which displays a vector-tiled view of all vessels up to a few days ago, not just fishing boats.
And something from my own blog which may be of interest: https://blog.datadesk.eco/p/sky-lapse-in-two-tone
I'm thinking that this can be a good pattern for photography portfolio sites. Voice over from photographer talking about his inspiration, walking through key memories, while letting the user browser around.
Re: the website itself -- the Mercator projection is an artifact of paper maps, and it greatly distorts features near the poles. Could we please use a true globe when rendering interactive maps?