Fujian guangdong haifang hanghaitu

This coastal defence and navigation chart of Fujian and Guangdong areas shows the details of the Pearl River Delta. Coastal charts had been made since the Ming dynasty to oppose invasions by pirates. Various navigation information is shown, including wind shelters used by ships, and there is an annotation that the waters between Kowloon and Hung Heong Loo (Hong Kong Island) are nine zhang deep (ninety Chinese feet, or approximately thirty metres), hence suitable for boats to be moored in this area while sheltering from the wind.