Digital surface model of the high resolution lidar model of the Hill of Tara, Co. Meath

Aerial Survey & Remote Sensing

Remote sensing is the science and technology of obtaining information about an object from a distance without physical contact. It can be used to describe many different methods which assist archaeologists to identify, understand and manage the historic environment, specifically larger archaeological sites, and archaeological landscapes. There are several different remote sensing methods and technologies which are used by archaeologists to record both surface and subsurface archaeological features. The nature of the archaeology which is being recorded and the scale of the features which are present determines which methods are applied. Remote sensing methods can be grouped into several categories:

  • Space/Satellite Imagery – The use of imagery and photography from existing satellite platforms for the identification of both visible and hidden features at a small scale or wider landscape level.
  • Aerial photography – The ability to capture photographs from a range of aerial platforms, from larger fixed-wing aircraft and helicopters to smaller UAVs or drones, enables us to observe and record the landscape. This technology is valuable at both the wider landscape level but is also a suitable approach for individual sites. Methods can include the simple documentation of a site through an aerial image to the use of photogrammetry to model archaeological features in 3D.
  • Aerial sensors – Airborne lidar (light detection and ranging), also known as Airborne Laser Scanning (ALS), provide precise 3-dimensional measurements of the ground surface, and the resulting models and imagery can help archaeologists to identify and record our cultural heritage. Different techniques can be used to manipulate this data and can even help to reveal features otherwise hidden under woodland cover.
  • Ground-based geophysical methods – Using a range of non-invasive techniques and specialist equipment we can detect features buried beneath the surface without digging. A range of approaches exist which measure variations in the physical properties below the surface to identify archaeological features and structures.

Many of these methods enable the detailed recording of surface and subsurface archeological features. Within the context of archaeology, this enables us to:

  • Observe patterns and relationships which cannot be seen from the ground.
  • To view invisible information that the human eye cannot perceive by using sophisticated sensors.
  • Collect data for large areas of the landscape.
  • Repeatedly observe areas to detect change.
  • Integrate data within GIS to enable the prospection, interpretation, and management of archaeological sites.

Each of these methods will be explored in more detail in the associated pages which are in development.