Mao Kun map is often seen as a surviving document from the expeditions of the mariner whose ships could stretch past what length?
Mao Kun map:  The map is often regarded as a surviving document from the expeditions of Zheng He in addition to accounts written by Zheng's officers, such as "Yingyai Shenglan" by Ma Huan, "Xingcha Shenglan" by Fei Xin, and "Xiyang Fanguo Zhi" by Gong Zhen.
i don't know