Aerial survey is the single most important tool for the discovery of archaeological sites in England.
Aerial survey is a broad term, used to describe the various activities related to the recording of sites and landscapes from the air; this includes the taking of new photographs, along with interpretation and mapping, using both new and archive photographs. It is one element of the broader field of remote sensing, that provides information about the ground surface and subsurface without direct contact, using airborne and satellite sensors and ground techniques such as laser scanning and geophysics.
The results of aerial survey can be used, either on their own, or together with other techniques, to investigate entire landscapes, feed into multi-disciplinary projects and directly improve the management of the historic environment.
Each year hundreds of previously unknown sites are discovered through the Aerial Reconnaissance programme and specialist staff identify even more through the analysis of features visible on existing aerial photographs.
Major projects are co-ordinated through the English Heritage National Mapping Programme. Individual sites are investigated to help understand important new discoveries or to help with their management.
History of aerial photography and archaeology
The earliest aerial views of Stonehenge date from 1906, but aerial archaeology really has its origins in the First World War. Methods used in that conflict were first brought to the service of archaeology in the 1920s by OGS Crawford.
Early discoveries such as extensive prehistoric field systems and the course of the Stonehenge Avenue demonstrated that an airborne camera could capture traces of sites no longer visible on the ground. Crawford used the journal he had founded, 'Antiquity', to publicise both aerial photography and the discoveries being made.
After the Second World War, the pace of discovery quickened as more civilian flying was undertaken. Aerial photographers discovered thousands of new sites, but were also instrumental in demonstrating the threats to archaeological sites posed by agriculture, quarrying and development.
Consequently, aerial photographs now aid the discovery and understanding of archaeological remains as well as their conservation and management.