Aerial remote‐sensing techniques used in the management of archaeological monuments on the British Army's Salisbury Plain Training Area, Wiltshire, UK

Abstract

AbstractSalisbury Plain Training Area, covering 38 000 ha in Wiltshire, southern England, is the UK's largest military training area. Military ownership has protected, from modern agricultural practices, over 2300 archaeological monuments dating from the late prehistoric and Romano‐British periods. Consequently the majority of sites still survive as earthworks.The Defence Estates is tasked with managing this landscape, balancing military, agricultural, archaeological and nature conservation priorities within a national and international legislative framework.The Defence Estates is evaluating the use of airborne LIDAR (light detection and ranging) and CASI (compact airborne spectrographic imager) surveys to map ‘condition’, results being directly transferable to a geographical information system. It is hoped, by comparing successive surveys, that trends can be identified, allowing management decisions to be reached. The work, funded by Headquarters Army Training Estate, is being conducted in partnership with the Environment Agency's National Centre for Environmental Data and Surveillance.An initial trial, covering 40 km2, was held in 2001. The capacity of LIDAR and CASI to identify areas of, and trends in, formation of bare ground, grazing, disturbance (military and animal digging) and scrub infestation was evaluated.Results showed that CASI imagery, particularly when processed as a normalized difference vegetation index (NDVI) image, was ideal for showing bare ground, scrub and levels of grazing, whereas LIDAR provided a means of measuring the magnitude of change. The techniques were less successful at distinguishing disturbed ground such as back‐filled military trenches. Combined LIDAR and CASI images were shown to be ideal media for identifying archaeological earthworks. The potential for the development of automated trend analysis was proved but manual systems were shown to be more appropriate.Development work is continuing and it is hoped to have a remote‐sensing‐based monitoring system in place on Salisbury Plain Training Area in the foreseeable future. Copyright © Crown Copyright 2002. Recorded with the permission of the controller of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.