Relies upon what you mean by "investigated" and how you ascertain it.
Let's assume we characterize "investigated" as "each bit of ground inside the hover made by most extreme viewable pathway of anyone whenever". No doubt about it just flying on a plane, you "cover" huge amounts of ground region. As per that definition, I'd expect a large portion of the Earth is investigated. effectively more than 80%.
Let's assume we characterized "investigated" as "showing up on Google Maps at any zoom level" at that point better believe it, practically 100% of the land is as of now "investigated".
Let's assume we characterize "investigated" as "100 feet around anyone strolling" at that point the % drops definitely.
Let's assume we characterize investigated as "contacted the ground there with hand feet or anyone part", at that point we didn't investigate everything that much yet. hell, there are presumably a couple of floor tiles in your own particular kitchen that still wouldn't consider having been investigated by you.
On the off chance that I remain in a major pinnacle supervising a garden, I can see the whole garden. In any case, I don't perceive what is directly behind that hedge over yonder. Does this mean I can't have "investigated" every last bit of it regardless of how hard I squint and take a gander at the garden from my pinnacle?