Use of satellite images and drones in surveying the northern part of the Tesinsky archaeological microdistrict in Bogradsky district of the Republic of Khakassia

Works on mapping the Tesinsky archaeological microdistrict in Bogradsky District of the Republic of Khakassia started in the field season of2020. Research was conducted in the northern part of the microdistrict (left bank of the Tes River), bounded by the Korova Ridge on the north and west, by the Krasnoyarsk Reservoir on the east, and by the Tes River on the south. A number of sites were discovered in the area under study in different years; the Kopyonsky chaatas and Tesinsky Zaliv-1 burial ground have remained outside the flooded zone. The works were aimed at searching and identifying archaeological burial sites using the method of aerial survey with integrated use of satellite imagery and drones; research objectives included developing the working algorithm, mapping the survey area, and making a qualitative assessment of working stages (analysis of satellite images, field survey, and drone survey). At the preliminary stage, groups of objects were located using satellite images. This information was checked during the field survey, and preliminary boundaries of the groups were established. Drone survey was conducted based on these boundaries, after which ground photographing with the GPS-tags was done. The results of the field survey were correlated with orthophotomaps; additional survey of the objects missed during the ground work was done. Point clouds, elevation maps, topographic plans, and orthophotoplans were built using Agisoft PhotoScan, Surfer, and Global Mapper software. This work resulted in detecting eleven burial grounds and individual burial mounds of the Tagar culture. The necessity of adjusting the boundaries of the Kopyonsky chaatas has been confirmed, since a series of burial mounds of the Tagar culture and large burial ground of the Tashtyk culture have been identified in the territory adjacent to the Kopyonsky chaatas on the north. Qualitative assessment of effectiveness of analyzing satellite images, field survey, and drone photography was performed.