University of Southampton OCS (beta), CAA 2012

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Above and below: an integrated approach to the analysis and visualisation of data from topographic and geophysical surveys
John Pouncett, Christine Markussen

Last modified: 2011-12-13

Abstract


This paper outlines an integrated approach to the analysis and visualisation of remote sensing data developed as part of ongoing research focused on the Iron Age hillfort at Moel-y-Gaer Bodfari in Denbighshire, North Wales. Moel-y-Gaer Bodfari is one of a series of well-preserved Iron Age hillforts on the Clywdian Range, a group of hillforts which until recently have been studied little and were poorly understood. Topographic and geophysical surveys were carried out as part of the initial phase of a research project intended to place the hillfort into its wider landscape context. Research is intended to provide a rich dataset for comparison with other Clwydian hillforts surveyed as part of the recent Heather and Hillforts project and inform our understanding of the chronological and social complexities of these sites. A wide range of complimentary datasets were generated during the course of the initial phase of research at Moel-y-Gaer Bodfari, including surface data from the analysis of LiDAR data and conventional topographic survey and sub-surface data from multi-sensor and multi-depth geophysical surveys. An integrated approach was developed to synthesise these datasets and provide baseline conditions for subsequent phases of the research project. This approach comprised three elements, namely: 1) morphometric analysis of LiDAR data to extract features, generate break line plots and produce an interpretative plan of the hillfort and associated earthworks; 2) multivariate analysis of LiDAR, magnetic and resistance data to locate and identify any potential archaeological features/deposits within the interior of the hillfort, and; 3) voxel-based visualisation of LiDAR and multi-depth resistance data to assess the structure and configuration of the ramparts and entrance(s) to the hillfort. Integration of the surface and sub-surface datasets has significantly enhanced understanding of the Iron Age hillfort at Moel-y-Gaer Bodfari, identifying previously unrecognised earthworks including an inner rampart in the south-west quadrant of the hillfort and a counterscarp or rampart along the eastern edge of the hillfort. The approach used to integrate these datasets has wider utility beyond the study of a single site and extends existing approaches to the analysis of LiDAR data and data fusion employed in archaeological research.


Keywords


LiDAR; Topographic Survey; Geophysical Survey