Question About Laputa

Hey everyone, so I'm watching Castle in the Sky right now and I just got past the part where Patsu shows Shita the journal his dad kept about Laputa. In Patsu's story his father only manages a brief glimpse of the Island and a shoddy picture. But then he says that his father wrote about the people who lived there. What do you all think about this? Did his father do research elsewhere? Or maybe he just created his own fiction on what the island was like. Or maybe I'm just looking too far into this...