The Kangxi Emperor employed Jesuit brothers (1708–18) to produce maps of the provinces of China using a combination of Western and Chinese survey methods. The maps were completed by 1721. They were sent back to Europe and
became the basis for maps of China produced by Jean Baptiste Bourguignon d’Anville in 1735. The main changes from
traditional Chinese mapping were to use latitude and longitude as primary coordinates, map them using a spherical
projection, and use astronomical measurements of latitude and longitude to establish baselines. Changes in latitude and
longitude were found using traditional metric survey and relationships between distance north–south and latitude and
distance east–west and longitude to convert to degrees. A digitized facsimile of the 1721 map series is available from the
US Library of Congress. In this article, the digitized images were used to reconstruct the parameters of the sinusoidal
projection, establish scale, and re-project and mosaic the maps into various forms for presentation. The accuracy of
five of the province maps is discussed in detail. It is found that poor astronomical measurements of longitude are the
most serious issue for the maps, but that apart from areas distorted by the poor longitude estimates, the accuracy was
commensurate with that of European land maps of the time.