Maps and supporting materials for the Kangxi Jesuit Maps of 1721 Project
The Yan Ruyi Map Region in the Kangxi Jesuit maps of 1721:
In 1808, the scholar official Yan Ruyi (严如熤, 1759~1826) was appointed as Hanzhong Zhifu (Prefect). While he was in Hangzhong, Yan Ruyi managed the production of the “Hanzhong Gazetteer” and was engaged, with the help and support of an artisan map maker called Zheng Bingran, in a much more extensive mapping activity of the Qinling and the border regions of Shaanxi, Sichuan, Hubei and Gansu. These efforts were in response to the Qing government's need to gather information to provide greater security throughout the wild border region of the four Provinces. Further information including maps and translations can be found on the Qinling Plank Roads to Shu web site HERE. The Kangxi Emperor had earlier employed Jesuit mathematicians (1708-1718) to design and manage the production of a set of maps of the provinces of China using a combination of western and Chinese survey methods. The mapping was completed and the first maps presented to the Emperor in 1718 and finally in an updated form in 1721. The maps remained secret in China and were not used outside the court until updates were made in the late 19th Century. The maps were, however, quickly sent back to Europe by the Jesuits and became the basis for maps of China produced by Jean Baptiste Bourguignon d'Anville in 1735. In this way, European maps became highly accurate and detailed for China's interior just as European interest was increasing in the opportunities China presented for trade and imperialist ventures. The main change from traditional Chinese mapping was to use Latitude and Longitude as the primary coordinates and use astronomical measurements of latitude and longitude at selected places to establish baselines. Changes in latitude and longitude between other places was then found by first using traditional metric survey to obtain distances and then using relationships between distance north and south and latitude and distance east and west and longitude to convert distances to degrees. The relationships between distance and change in latitude were established by survey measurements and based on a spherical earth model. A re-printed version of an early set of maps taken back to Europe can be accessed from the Digital Library of the US Library of Congress. The digitised images have been used to reconstruct the parameters of the original sinusoidal projection and then re-project the maps into Geographical coordinates for presentation and view in Google Earth. The theory on which this activity and its application to the Kangxi maps was based has now been published as a paper in the Journal "Cartographica". Finally, a mosaic of the re-projected data within a set of latitudes and longitudes was generated from the set of maps. The bounding Box defined the area within which Yan Ruyi's mapping had been done. The objective is to estimate the scale and accuracy of the maps and use the Kangxi map mosaic with the various maps produced in the period when YanRuyi was at Hanzhong between 1813 and 1822 and finally to help mosaic as well as possible the various maps created during that time. For more general information about the context of the work, see Home Page of the Shu Roads Project Web Site
Documents relating to the Kangxi Maps
Published Journal Paper on the Kangxi Maps and Mosaic for the Yan Ruyi map area:
Background material and additional more detailed information about the project:
This document is a collation of research to date and more detailed data to support the Cartographica paper.
Translation of an important paper in Chinese by Wang Qianjin:
Maps of the Kangxi Jesuit collection published in 1721
The US Library of Congress has a large collection of ancient Chinese map materials. Among these are maps and map reproductions dating back some centuries. The Geography and Map Division of the Library web page can be found HERE. The Chinese Maps that are available can be accessed directly HERE. Images can be downloaded for use in research and other non-profit activities in GIF, JP2 (JPEG 2000), or JPEG compressed formats and (very large) Tiff files. However, only the JP2 and Tiff formats file have the resolution that allows view of all readable characters at the brush stroke detail level. For academic study, high resolution view of characters is therefore essential. If you wish to download and view the detail in these maps you will need suitable software to read JPEG 2000 and view the data. Possibly the best software available for this is IrfanView that can be downloaded from HERE.
The maps used in this work are available from the US Library of Congress web site. The holding of 35 maps of the Provinces of China at the time was originally published as:
The individual maps used here, after re-projection to Geographic, were cut to an overall area within which the Yan Ruyi maps were located. Then areas outside of province boundaries were digitized out. Finally, the various province sections were put together into a mosaic. The five provinces images used here are available as JPEG QuickLook images in the Image Table below. One of the scanned maps (in sinusoidal projection) shown immediately below:
Table of Jpeg images of Kangxi maps covering the Yan Ruyi mapping region (use "back" to return to Table)
A (large) 55 MB zip file containing all of the Jpeg images in the Table can be downloaded HERE.
Google Earth Superoverlays and Base Mapping Reference Points
The age, presence of strong folds, paper stretch and local irregularities common in wood block prints means that there are some areas of poor printing and some additional metric distortion in the maps. The distortions were compensated for by using additional control points. For added accuracy of the mosaic, constraints minimizing mis-registration between boundaries in adjacent maps were also added. As a result, the mosaics had few problems where the borders met. Google Earth Super Overlays of the maps (using network links to the data) have been produced and are made available for download here:
The above screen image of the set of Superoverlays shows the extent and nature of the maps. They were re-projected to geographic coordimates and so the grid lines are vertical and horizontal and equally spaced in latitude and longitude. By zooming in close to the image it is possible to read almost all of the characters for the place names. In some places the printing is quite faint which is a nuisance and in others there are some distortions but the maps provide a good base for studying accuracy and scale. For example, it is possible to establish that the maps are all at the same scale of 1:1.935 Million. Basic accuracy has been established in a number of ways. There were about 300 base mapping points (places) that were visited by the surveys recorded and given in a Gazetter in the French edition of du Halde's book. The Gazetteer provided Latitude and Longitudes with Longitude as East or West of Beijing. Very good estimates of positions of later Qing places (1820-1880) down to District Level have been provided on the web in the ChinaW set from CHGIS at Harvard University. A full discussion of how these data sets have been used to establish map accuracy is available in the Cartographica paper with some additional details in the supporting document listed above. In the mosaic area, the underlying RMS error for Latitude and Longitude is about 8-10 km. This would be regarded as very accurate for most European maps of this time and better than some other European maps of China produced up to the fall of the Qing.
The set of Google Earth super overlays also contains a Mosaic of all five Provinces. It is very large and is most easily accessed as in this case via the Web. When first displaying allow some time for the large area superoverlay images to download and settle. The response will be a little slow until the cache fills up. This super overlay allows you to view the readable characters and so it forms a very valuable data base. When the 15 provinces are available it will be a massive data set able to be accessed at the most detailed scale as well.
Current activity in the Kangxi Maps Project
The work reported in the Cartographica paper aimed to set up a mosaic for the Yan Ruyi area. Since that time, the same study has been extended to the full 15 Provinces of "inner" China. The images have been balanced, cut and put into a full Mosaic. Current work is finalising the super-overlays, making presentations of the du Halde points for the Provinces and reporting the additional findings that have come from the full set of Provinces. It is planned to set up a new page for this work. In addition, another Project has been to use the techniques with maps brought to Europe by Martini Martino and the Kangxi maps of the Jesuit Brothers that were redrawn by Jean-Baptiste Bourginon d'Anville. There is interest in the relative accuracy of the maps with the Kangxi 1721 set. This work has been completed and is being reported and its images and super-overlays will be another web page. The two new web pages will be accessible from this page and when they are ready it will be announced in "What's New?".