Maps had for centuries played an important role in the government of China. This drove Chinese map technology to the frontier, employing techniques still utilised in modern cartography. For example, surviving
map examples on stone dating from AD 1137 but based on much earlier surveys, show great accuracy using a
grid system; by then the Chinese had also developed the magnetic
compass. By the early years of the 14th century, when
Mongol domination over much of
Eurasia created favourable conditions for east–west communication,
Islamic maps of Europe and Africa found their way to China, encouraging Chinese cartographers to create world maps incorporating the new information. Scholars consider that the
Da Ming Hunyi Tu was based on a now lost world map named
Shengjiao Guangbei Tu (聲教廣被圖). It was created by Li Zemin during the Mongol Yuan dynasty. Other extant maps considered to be based on Li's map are some copies of the
Kangnido (1402) and a pair of maps named
Dongnan Haiyi Tu (東南海夷圖) and
Xinan Haiyi Tu (西南海夷圖), which is recorded in the
Guang Yu Tu (廣與圖) (1555) by
Luo Hongxian (羅洪先). Comparative studies of these extant maps are conducted to restore the content of Li's original world map. The
Da Ming Hunyi Tu is especially important because Luo's copies dropped most place names except for coastal areas and islands and because the
Kangnido was influenced by Korean cartography. Compared to the
Kangnido, the
Da Ming Hunyi Tu provides more detailed information on Mongolia and Central Asia and India. In Manchuria,
Changbai Mountain, where the foundation myth of the Manchu
Aisin Gioro imperial family was set, is overly portrayed. It presents India as a peninsula while it sinks into the "Chinese continent" on the
Kangnido. It is presumed that India was portrayed as a peninsula on Li's map but shrunk by Korean Confucians due to their anti-Buddhist policy. Africa and Arabia on the
Da Ming Hunyi Tu resemble those on the
Kangnido while Europe is considerably different. It is also distinct from the
Kangnido in the depiction of the source of the Yellow River, which looks very similar to that in Luo's
Guang Yu Tu. ==Content==