Integrated RS, GIS and GPS approaches to archaeological prospecting in the Hexi Corridor, NW China: a case study of the royal road to ancient Dunhuang

According to historic records, the wasteland northeast of modern Dunhuang oasis contains remarkable, undiscovered monuments of medieval courier stations. In this study, statistical analysis of historic records and census data, image processing and interpretation of satellite remote sensing images, GIS analysis, and field surveys were carried out to contribute to the discovery of courier stations and the reconstruction of the medieval royal road system from Guazhou to Shazhou. Firstly, in order to obtain the existence regions of courier stations, historic records and census data were abstracted and digitized, for generating preliminary regions of interest by using GIS tools. Secondly, dried river channels and traces of the Great Wall were extracted from the remote sensing images, and GIS buffer and overlay analyses were applied to the creation of prospective sub-areas. Thirdly, prospective sub-areas were mapped from very high resolution WorldView-2 images, and suspected sites were found based on the human-computer interactive interpretation. Fourthly, suspected sites were investigated on the GPS-based archaeological survey, and were confirmed as two courier stations based on the remains of Han-Tang period observed at sites' surface. Lastly, the royal road to ancient Dunhuang, one of the most important sections of the royal road system in the Hexi Corridor, was discussed and reconstructed with the combined application of remote sensing imagery and ground-truthing.