Preventive archaeology

Aerial photography is carried out by taking dedicated oblique photographs from small aircraft. Most archaeological sites become visible through colour signs (in the soil) or vegetation signs (different growth and ripening of crops) and under specific conditions (drought, floods, low light, certain stages of plant growth). The extensive archive of Cyclical Aerial Photography (CAS) of the territory of Slovenia serves both to identify new archaeological sites, to monitor their condition, and to monitor changes in the whole area.

Within registered archaeological sites, the Centre for Preventive Archaeology carries out investigations to determine the content and composition of the site, which may take the form of intensive field surveys, drilling and hand-network excavation, and the excavation of machine test trenches with documentation. Preliminary archaeological excavation as a method is only used in cases of imminent physical threat to an archaeological site, when the site cannot be protected in space. It also carries out parallel underwater research in the form of extensive and intensive underwater surveys, underwater test probes and underwater archaeological excavation.

Remote sensing methods include geophysical surveys. Unlike other remote sensing methods, measurements are taken directly at the ground surface, not from the air. By measuring certain physical properties of the subsurface record, archaeological remains can be detected without physically disturbing them. The most commonly used geophysical methods, which are largely complementary in their message and are therefore often used together, are: the resistivity method, the magnetic method and the GPR method. The advantage of these methods is that they are non-invasive, as they do not interfere with the archaeological remains.

Laser surface scanning, often referred to as lidar, is a remote sensing method that can measure the Earth's surface with high precision. Lidar is a very suitable method for use in Slovenia due to its ability to observe the ground under forest cover. In order to be able to observe archaeological traces with lidar, they must be visible on the surface as bumps and protrusions, traces such as embankments, walls, dykes, or trenches, pits and ditches. Lidar has been used to discover a multitude of new archaeological sites, such as mounds, hillforts, castles, as well as new types of sites and traces of the past such as limestones, cairns, medieval fields and the like.