[danielsamuels]

The website claims the longest line of sight in my city is 24.7km from someone's garden that is surrounded by houses. I walk past this particular spot on my way to the gym. I walk downhill from my house to get there. I seriously question the reliability of this data.

[tombh]

The resolution of the underlying data is only ~100m. So most houses, vegetation, etc, gets blurred into the same smooth surface. There are actually higher resolution data sets, even up to centimetre scale, using LiDAR, of cities. We'd love to integrate these but it's a few orders of magnitude more data.

[DiggyJohnson]

I think you're assuming more fidelity than the project is claiming

[danielsamuels]

I'm assuming that when the project says you can see 24 km from a given location, that you can see 24 km from that location. That's not the case. Fundamentally, it doesn't do what it claims to do.

Why allow the user to select any arbitrary location on a map and give an answer when you know the answer is most likely nonsense? You don't need to compute for 2 days to accomplish that; you could just make it up.