## 2 Materials and Methods  
The Markul Expedition used two main digital technologies: geographic information systems (GIS) and photogrammetry. The results of the latter were additionally integrated into the GIS, i.e., a technology for integrating factual electronic databases (text, digital, etc.) and geo-images. Simultaneously, an important feature of any modern GIS is the option for continuous expansion by adding new layers and connecting new databases [8]. Archaeological research in the territory of Abkhazia, which aimed at forming a GIS of archaeological sites, was started by the Institute of Archeology, RAS, in 2001 and now includes 1780 objects, including dolmens, temples, fortresses, settlements, and burial grounds; however, there are no architectural remains above the surface of the earth. The Markul Archaeological Expedition used ArcMap in the work. Data obtained from the public domain in 2009 ASTER GDEM were used as the basic geographic layers. In addition, 1:100,000 and 1:250,000 scale geographical and topographic maps, which cover most of the coastal area, and vector data derived from raster topographic maps were utilized. GPS coordinates of archaeological sites were found in the course of field studies of the territory (Figure 2). Figure 2: Overall map of archaeological sites, visualized from GIS (the sites named in the text are indicated by numbers). The primary database of archaeological sites contains the following main items:  
1. Title. 2. Type of site. 3. Ancient (antique or local) place name (if any). 4. Link to mention in sources (if any). 5. Bibliography (if any). 6. Names of researchers of the site (if researched). 7. Years of study of the site (if researched). 8. Description of the site. 9. Level of preservation. 10. Modern use of the territory. 11. Area (if defined). 12. Dating. 13. Interpretation. Because the level of preservation and research of sites differ, the primary database was constantly updated by applying layering and hyperlinks. Some of the most crucial layers of information are the filmed orthophotmaps of settlements and 3D models of sites. Concerning the Markul settlement, stationary studies, some of which have been conducted by our expedition since 2014, and photogrammetric models of excavations and individual artifacts were added to the GIS (Figure 3). Figure 3: Implementation of layering and hyperlinks in GIS: (**a**) orthophotmaps of the Markul settlement (Figure 2, No. 6); (**b**) orthophotmaps of the protective tower excavation, with the excavation site integrated as a separate layer in the GIS; (**c**) GIS hyperlink in the photograph of artifacts found at the castle excavation site; (**d**) Alakhash tower outlines in the orthomosaic and hyperlink in the photo, 3D model, and reconstruction of the tower. In a broad sense, photogrammetry is a technical discipline that creates a 3D image of an object from a series of digital photographs, which allow one to record the current state, measure geometric characteristics (dimensions, areas, and volumes), study textures, and obtain all the necessary drawings, projections, and cuts. Photogrammetry methods were applied in archeology even in the pre-digital era and were mainly associated with the analysis of aerial photography materials [3]. The development of computer technology gave a powerful stimulus to the development of photogrammetry methods and made it possible to automate image processing using a personal computer, which increased its availability and significantly expanded the limits of the technology. In the last decade, as a result of the development of computer resources, photogrammetry has become widespread in field archeology, museums, architecture, restoration, and other scientific areas and applied activities related to the preservation of cultural heritage sites. In the Markul Expedition's work, photogrammetry has been applied since 2017 and has become an integral part of the work, complementing the classical methods of documentation [9, 10, 11].