The Exploration of the Ancient and Modern Measuring Points of the South China Sea: Scientifically Positioning in accordance with the Pictures" />
four seas measurement, combined survey for the islands and reefs, surveying and mapping, astronomical surveying, the South China Sea, the South China Sea Islands, Huangyan Island,"/>
“ Four seas measurement” in the Yuan dynasty is the latitude surveying in ancient China,namely astronomical surveying or astronomical geodetic surveying. The combined survey for the islands and reefs in the South China Sea research in the 20Th century is not only the innovation project of marine research in China, but also the first ever marine geodetic survey in the South China Sea. The paper overviews the “four seas measurement” and the “combined survey for the islands and reefs”, and juxtaposes the ancient South China Sea survey points calculated by professor Han Zhen-hua and the contemporary geographical position of Huangyan Island on the same picture, which provides a precise and reliable scientific basis for the research and verification of the South China Sea survey points in the “four seas measurement”.