Archaeology is the study of the physical remains of past human societies. Archaeologists look at both upstanding monuments (for examples, buildings that are clearly visible) and sub-surface remains (material found in the earth that has been gradually covered over as time progressed). The use of remote sensing in archaeology is the use of numerous non-invasive techniques to study sites and monuments that are of interest to scholars. This article will first describe some of the techniques of remote sensing that are used by archaeologists and will then go on to outline their importance for research into our past.
For archaeologists, remote sensing usually refers to either imaging or sensing of distant characteristics that are used to indicate the presence and the layout of archaeological sites and landscapes. The techniques used can include some, such as aerial photography, that have been in use for a long time, or more recent developments such as lidar, ground-penetrating radar and magnetometer surveys. These are the techniques that will be discussed briefly here.
Aerial photography, images from a height, are used to get a bird’s eye view of archaeological sites. Often it is possible to see features, such as crop marks (where changes in soil caused by the presence of levelled archaeological sites can cause differential crop growth), that are not normally visible on the ground.
-Lidar (Light Detection And Ranging)
Like aerial photography, this is usually an aircraft based technique. It uses pulses of light and cameras that take pictures on multiple spectra to scan and produce digital images of an entire landscape.
-Ground Penetrating Radar
Ground Penetrating Radar is used to scan below the surface of the ground. Repeated anomalies in the readout may indicate the presence of archaeological sites.
The earth has a fairly static magnetic field but human activity tends to disrupt this. Magnetometer surveys can therefore pick up areas of past human activity.
Most archaeologists use the results of archaeological excavations as the basis of their research. However, most also believe the mantra that ‘excavation is destruction’. This means that as archaeologists peel away layer after layer of deposits on an excavation they are potentially also destroying any information it might hold. To mitigate against the potential of destruction archaeologists usually strive to make as complete and objective a record of the site as possible. This means that the site is preserved by record (as much as is possible) for posterity. The advent of remote sensing techniques has meant that in some cases it may not even be necessary to excavate any more, depending on what sorts of research questions are being asked. In other cases, the results from remote sensing may allow archaeologists to choose select areas of a site to open small excavations, rather than excavating an entire site.
This shows that remote sensing now plays a vital role in archaeological studies, and the key to understanding the importance of these techniques is the fact that they are non-invasive. They do not involve any interference with archaeological material because the techniques are remote. This is particularly important in the case of a finite resource such as our archaeological heritage.