You can add any GameObject to map.
This is called the 3d markers.
So Online Maps already has this feature.

I am looking for the feature in Online Maps what allows me to limit my terrain view.
So I have an Object, like a speedway. But I want the user to see only the driving object and a part of the map (like in Online Maps / birds view).

You can see the same in the game Godus:

I am using Unity 3D for mobile VR and need to limit the view distance. This is exactly what I am looking for and I would like to know if I have the ability to add my own objects to Online Maps?! So I would buy that asset if it is so.

Otherwise I would like to know what exactly I am looking for. So is there a specific name for that kind of 'boolean' operation?

Thanks in advance.
Baris