> I'd expect a fence or something else. To me it looks more like different paving on the ground.

Yeah, I see what you mean. To me the crosshatch pattern looked like the ribs you'd see on a pool cover. Perhaps I was a bit far out on a limb...

> But ultimately on the big G it is clearly visible as a pool.

Not to be smug here but...I was totally right 😉 Thanks for checking my work, I always learn something about interpreting aerial imagery.