Using the USSR General Staff maps to determine the geographical coordinates in archeology

Abstract

The main problem of archaeological plans drawn in the mid-20th century is that almost all of them have poor accuracy of spatial localisation of objects. Simple estimates show that the error relatively to the actual position of the site can reach several hundred meters on the Earth surface. Because of this, only large, well-preserved ob-jects can be identified using archaeological plans. If the monument is small and poorly preserved, then it is im-possible to distinguish it among modern buildings. This is especially critical if the search radius, which depends on the error in the archaeological plan, reaches 300–500 meters [Bolelov et al. 2019]. This situation complicates creation of modern accurate maps and geographical information systems. To specify the position of the monu-ments, we propose using maps of the General Staff of the USSR (GS), which contain the location details of a large number of archaeological sites. According to our estimate, the GS maps have an error of ca. 50 meters, which significantly reduces the search area. The idea is that, first, the site on the archaeological plan must be identified with the object on the map of the GS, and then the GS coordinates (SK-42) need to be recalculated to the WGS-84 ones of Google Earth. A simple method of conversion from the SK-42 coordinate system to WGS-84 and vice versa in the form of additive corrections to geographical coordinates is proposed. Estimates of random errors have been obtained, which are caused by the error in compiling and analysing the maps. Although numeri-cal estimates have been obtained for the territory of historical Khorezm, it is most likely that the same transforma-tions are applicable to other territories. The described technique has been successfully applied to the archaeo-logical sites of the Yakke-Parsan Channel, which, according to the map of E.E. Nerazik [2013, fig. 14], comprises 20 monuments. Of them, only six largest structures had an accurate identification. As a result of the research, we found and identified seven objects more. The comparison of coordinates made possible the preliminary identifica-tions, and final identifications were made after comparing the appearance of the objects with architectural plans. Other sites have not been found because they have not been preserved to our time. Nevertheless, the GS maps allow obtaining accurate coordinates of the lost monuments.

Keywords

• archaeological sites
• determination of geographical coordinates
• mathematical proces-sing of maps
• khorezm.