I made no complicated scaling at all. Actually i didn't even need it(in this case). There is something called view perspective which alters depending on the way you see the object but in this case you don't need to take that into consideration because dressrosa is a circle and the king plateau is situated at the middle
You must be registered for see images
You must be registered for see images
That means in that case that the height and diameter meet each other, which means that the height of the plateau can be scaled to the diameter completely
I just showed the lines for people to see the difference for themselves. You don't need to be a pixel scaling expert to see the royal plateau's length is roughly 16times smaller(actually 15 now that i rated it) than the diameter of the dressrosa island. But if you're blind, i made it easier for special cases such as yourself
You must be registered for see images
Now if it is math problems, there i can't help you though unfortunately