Light detection and ranging (lidar) in the Witham Valley, Lincolnshire: an assessment of new remote sensing techniques

Abstract

Airborne light detection and ranging (lidar) allows the identification and accurate recording of upstanding features on the ground to sub-metre accuracy.The technique has previously been tested in areas of known high monument density such as the Stonehenge World Heritage Site with exciting results, but it is also proving usefulin less spectacular areas.This paper willlook at some recent work carried out by the Aerial SurveyTeam at English Heritage concentrating on an area in the WithamValley, east of Lincoln in the east of England.The area has recently been covered by an archaeological aerial survey project as part of the National Mapping Programme; examining the lidar data for the same area has revealed some interesting results. Lidar clearly has potential for recording certain site types and especially in highlighting relationships between sites in the broader landscape, but there are limitations with the standard off the shelf data due to issues of spatial resolution. The study also makes clear the importance of not using lidar data alone, but ensuring that it is part of an examination of all readily available sources.

New Developments in the Use of Spatial Technology in Archaeology

“…However, the spatial resolution of data is a limiting factor. If we return to Crutchley's (2006) study outlined above, the author notes that in one case a previously documented set of Bronze Age barrows were not detectable even when researchers exaggerated the elevation scale of their digital model to 20 times normal in a futile effort to portray and pick these subtle features out from the surrounding landscape.…”

“…But most research has taken advantage of satellite imagery like Landsat, SPOT, IKONOS, Quickbird, CORONA (declassified 2002), and ASTER (advanced spaceborne thermal emission and reflection radiometer) (Altaweel 2005;Challis 2007;Challis et al 2002;De Laet et al 2007;Masini 2006, 2007;Lasaponara 2006, 2007;Tan et al 2005;Winterbottom and Dawson 2005). We also have seen increased use of satellite imaging radar (SIR), synthetic aperture radar (SAR), airborne imaging radar (AIRSAR) (Evans et al 2007;Holcomb 2001;Shimoji 1995), and aircraft-mounted scanners that use light detection and ranging (lidar) to create digital elevation models (DEM) of the earth's surface (Carey et al 2006;Challis 2006;Crutchley 2006). In the UK, high-resolution lidar (1-2 m) has proved especially useful, allowing prospecting on par and exceeding that possible with air photography (Bewley et al 2005).…”

“…Light detecting and ranging, or lidar, uses aircraft laser sweeps to create remarkably detailed models of ground topography that can in turn be used for a range of purposes such as survey and archaeological prospection (Bewley et al 2005;Carey et al 2006;Challis 2006;Challis and Howard 2006;Crow et al 2007;Crutchley 2006;Devereux et al 2005;Harmon et al 2006;Kvamme et al 2006b;Powlesland et al 2006;Rowlands and Sarris 2007). Of the myriad of new laser mapping available, lidar is perhaps one of the most useful for archaeology since recording landscape topography is a regular part of surveying.…”

“…These include range finders (Hayakawa et al 2007), terrestrial 3D scanners (Karaim 2002), and lidar (Carey et al 2006;Challis 2006;Crutchley 2006).…”

On the Airborne Lidar Contribution in Archaeology: from Site Identification to Landscape Investigation

“…Anyway, it should be considered that some known features already recorded were not recognized by LiDAR. The majority of these were cropmarks or artifacts and buildings Crutchley (2006) used LiDAR data derived from UK Environmental Agency to analyze four different case studies (Southrey, Barlings cemetery, Stixwould, Bardney environs). He employed a vertical scale exaggeration of elevation to analyze the LiDAR data for microrelief identification.…”