Ambiguity with the Top View of a binary tree

What exactly is the top view of a binary tree?

I find great ambiguity and lack of clarity from the articles I find.

For example, this is what is used to demonstrate the top view on geeksforgeeks:

       1     /     \    2       3   /  \    / \  4    5  6   7  

They go on to say that the top view is 4 2 1 3 7. The problem here is that they leave a lot of speculation on what isn’t the top view. Consequently it becomes ambiguous to implement in code.

Stackoverflow examples are not any better. Hackerrank’s example is even worse.

So I have signed up here hoping someone will tell me explicitly what the top view is because I have been trying to find out for 2 days. For instance, what is the top view of this tree:

      1        \         14        /  \       3    15      / \     2   7        /  \       4     13      / \   /     5   6 10          /  \         8    11          \    \           9    12  

And if I may be bold to ask, why is it important?