Landesamt für Denkmalpflege und Archäologie Sachsen-Anhalt
Landesmuseum für Vorgeschichte
Deutsch | English

Archaeological Surveying

The Law of the State of Saxony-Anhalt for the Protection of Historic Monuments sets out as one of the core tasks of the State Office for Heritage Management and Archaeology that archaeological monuments are to be identified, have their location noted precisely, and be recorded in a list. To find them, four methods of archaeological surveying are used: 1. Aerial survey, 2. Lidar (airborne laser scanning), 3. Field survey, and 4. Geophysical survey methods.

Aerial survey

Roitzsch, Landkreis Bitterfeld. Crop marks
Roitzsch, Landkreis Bitterfeld. Crop marks. Mediaeval Slavonic village 'Radekin'. Circular village with defensive ditch, house sites and fields. © LDA Sachsen-Anhalt. Photo: Ralf Schwarz.

The use of aerial survey offers a high success rate when surveying for unknown archaeological monuments. This is because by plane it is possible to survey large areas in a short space of time. The success of the method is above all due to the fact that the growth patterns of grain crops react to archaeological structures beneath the ground and thus make the type and extent of the archaeological site visible. In this way, the invisible remains of settlements hidden in the ground are revealed, and the form of the site can be seen, with graves, houses, ditches, and so on. Since aerial survey was begun in 1991, around 6000 archaeological sites have been discovered from the air and documented in more than 80,000 pictures. To provide a continuous, systematic and exhaustive aerial survey of the whole of Saxony-Anhalt, resources are at present made available for 75 flying hours annually.

Lidar - Airborne Laser Scanning

Digital model
Mediaeval castle and motte in the Ziegelroda Forest near Wangen, Burgenlandkreis. The digital model of the terrain is based on lidar data (resolution 0.5 m, vertical precision 0.1 m).

Aerial photography can only reveal archaeological sites on agricultural land, above all through crop marks on fields of grain (but only on fields planted with barley, wheat or maize), so wooded sites cannot be identified by this method. Forest is exceptionally good for preserving monuments, because grave mounds and ramparts have not been as exposed to the elements as would be the case in open terrain, where they are also levelled by ploughing, but it can be very difficult to record them, because thick undergrowth and bushes make access difficult.

For this reason, the Conservation Office uses the most modern methods, such as lidar (airborne laser scanning), in which laser pulses from a plane penetrate through the branches of the trees and are reflected back off the ground, making it possible to map out the relief of the ground-surface. Using mathematical methods, it is then possible to create a high-resolution digital terrain model (0.5 m raster) of the ground surface, which depicts even very small irregularities in the ground level, and thus reveals barrows, earthworks, hollow ways, and so on. The data can also be used to create three-dimensional models. In this way, lidar assists and facilitates the task of surveying in forested terrain.

[Translate to Englisch:] Geländeprospektion (Feldmethode)

Battle of Lützen 1632 (1)
Battle of Lützen 1632: Positions of the Swedish and Imperial troops, with the survey areas of 2006 marked.
Battle of Lützen 1632 (2)
Battle of Lützen 1632: survey areas of 2006, with positions of lead bullets marked, distinguished by calibre.
Battle of Lützen 1632 (3)
Battle of Lützen 1632: Advance of the Swedish army under Gustavus Adolphus II, with the positions of the lead bullets, distinguished by calibre, marked in the background.
Kuckenburg near Esperstedt
Kuckenburg near Esperstedt, Saalekreis. The site was surveyed by Christian Schweitzer with a high-sensitivity caesium magnetometer. The magnetogram shows the mediaeval castle complex on a promontory above the Weida valley as well as prehistoric defensive ditches.

Field surveys to identify archaeological monuments are carried out by the Conservation Officers, supported by the voluntary archaeological Conservation Representatives. The method of field survey is based on the fact that material remains of prehistoric, ancient and mediaeval humans, especially potsherds, which are mostly buried in pits or settlement levels, are brought to the surface through ploughing and are spread on the surface of the field, where they appear as scatters of small pieces and yield information on the type and size of the settlements or burial places hidden under the ground. To record these pieces of evidence for human settlement in their precise position, GPS (global positioning system) instruments are used, with which the coordinates of the finds can be recorded to a precision of about 5 meters.

To carry out this work effectively, an exact knowledge of the topography of the terrain is necessary and this is provided by a network of local residents who work on a voluntary basis as Conservation Representatives. Other tasks are the regular inspection of monuments that are preserved above ground, to check for damage, total or partial destruction, theft (e.g. of small monuments like stone crosses, milestones etc.), or pollution, and also to inspect construction work for the possible occurrence of archaeological elements.


To identify modern battlefields, a further method has become established: battlefield archaeology. In the survey, selected areas of the battlefield are walked over with metal detectors. The survey is carried out in a pegged-out grid of squares along survey lines. Where finds are seen or, in the case of metal finds, identified by acoustic signals, the finds are recovered, their position is recorded with GPS and they are packed into a finds bag. The goal of the survey is to record and map all the finds: bullets, pieces of uniform, equipment, coins, parts of cannonballs etc., parts of horse-harnesses, human and animal bones, pottery, etc. Thanks to the identification and mapping of the finds in GIS (geographic information system) software, it is possible to form conclusions about the extent of the battlefield, the course of the battle, the positions of the camps, composition of the troops, and so on.


Geophysical survey

Using geophysical remote sensing techniques, it is possible to depict structures that are buried in the ground, and therefore unknown to us (e.g. defensive ditches, houses, cemeteries), in a way that shows their position accurately. The disturbances in the ground that are associated with them produce differences either in the electrical conductivity of the ground or in its magnetic field. While electrical sensing is used to identify buildings with stone foundations, magnetic sensing is used to identify filled-in hollow forms like graves and pits. Larger surfaces are surveyed with a high-sensitivity caesium magnetometer by Christian Schweitzer on behalf of the Conservation Office, while smaller projects are surveyed by the Conservation Office staff member Gerd Virkus with a fluxgate gradiometer. Because of their direct mapping of the structures hidden in the ground, geophysical methods deployed prior to a planned excavation contribute to the efficient execution of the project and also to more reliable planning in the calculation of costs. In addition, it is possible to establish the extent and type of archaeological monuments involved.