Question: Mao Kun map is often seen as a surviving document from the expeditions of the mariner whose ships could stretch past what length?
Sentence (from "Mao Kun map"): The book was compiled by Mao Yuanyi in 1621 and published in 1628; the name of the map refers to his grandfather Mao Kun () from whose library the map is likely to have originated.
Relevant evidence: No