Since the Nascas, Incas, etc. didn’t have balloons or airplane, how could they see where the image was pointing? If they had the equivalent of design maps of the image’s layout, they might be able to pick out the salient feature that pointed to water.
I personally think that the key lines point towards the “Lamaburgers Inn” franchise stores in the area.
PS:> I did some work exploring the area around Tikal so I’m open to all kinds of theories.
Actually, it has been suggested that the people, who obviously had too much time on their hands and made the figures, did have balloons. Also at some point someone claimed to have found the small scale models of some of the figures; the models were then scaled up using ropes or whatever to measure.