Talk at UNC Greensboro


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A talk to the UNCG Archaeology, Anthropology and Geography Societies / departments, April 2013

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Talk at UNC Greensboro

  1. 1. UNC Greensboro 5th April 2013 Beyond the Visible -maximising the potential of airborne remote sensing data for archaeological feature detection Rebecca Bennett Postdoctoral Associate, Wired! Lab Art, Art History and Visual Studies, Duke University
  2. 2. UNC Greensboro 5th April 2013Historic landscapes and airborne remote sensing data
  3. 3. UNC Greensboro 5th April 2013 Image: Stonehenge, 1906 © English Heritage NMR‘The surface of England is a document that has been written on and erased over and over again; and it is the business of the archaeologist to decipher it’                                                                                                               OGS Crawford 1953
  4. 4. UNC Greensboro 5th April 2013Airborne Remote Sensing for ArchaeologyTwo types of features detectable from the air: Direct e.g. changes in topography Proxy e.g. changes in soil or vegetation properties
  5. 5. UNC Greensboro 5th April 2013  Spot the features...  Direct topographic change associated with a Neolithic henge monument Knowlton Circles Complex, Dorset UK © NMR
  6. 6. UNC Greensboro 5th April 2013 National Mapping Programme, English Heritage Mapping and archaeological interpretation of all archive aerial photography from 1945 onwards Began in the 1990s By 2009 40% of England mapped, 50% increase in known
  7. 7. UNC Greensboro 5th April 2013Issues of vegetation coverCropmarks at a protohistoric site at Grézac, France
  8. 8. UNC Greensboro 5th April 2013 Issues of seasonality 11 July 1989 25 July 1990Etton, Peterborough UK, reproduced with kind permission of R Palmer
  9. 9. UNC Greensboro 5th April 2013 Timing Critical! 17 June 1976 – parts of two vertical photographs taken 6 seconds apartEtton, Peterborough UK, reproduced with Kind permission of R Palmer
  10. 10. UNC Greensboro 5th April 2013Information can only be captured when it is visible... Region of higher stress sensitivity Standard AP Topography visible dependent of sun angle and azimuth Vegetation stress is best identified in non- visible wavelengths (NIR)
  11. 11. UNC Greensboro 5th April 2013Incorporating “New” technologies for Archaeological SurveyDirect Features (topographic change): Airborne Laser Scanning / Lidar
  12. 12. UNC Greensboro 5th April 2013 Welshbury Hillfort, GloucestershireImages courtesy of the Forestry Commission © Cambridge University ULM
  13. 13. UNC Greensboro 5th April 2013Proxy Features (vegetation and soil change): Airborne Spectral Imaging Digital Spectral Imaging Many materials, including vegetationand soils, reflect more Standard AP energy outside the visible spectrum,particularly in the NIR
  14. 14. UNC Greensboro 5th April 2013Project AimsContribute to understanding of ‘new’ sensors non-arable landscapes Why? - Unique and challenging landscapes - Overlooked in favour of arable areas - Wealth of information about past human environmental interaction - Impact on modern landscape management What? - Proof of concept for archaeological prospection using airborne laser scanning and digital spectral data How? - Quantitative analysis of archive ARS data
  15. 15. UNC Greensboro 5th April 2013The Pilot Study Everleigh, Salisbury Plain, UK Archive Airborne Data - Lidar data (1m resolution) - Multispectral data (14 bands, 450- 980nm), January and May - 4-band vertical AP, 2006 and 2007
  16. 16. UNC Greensboro 5th April 2013 All data sources were assessed against the baseline of the Wiltshire Historic Environment Record (transcription of archive aerial photography) in two ways: Binary Visibility and % percentage recovery of individual features
  17. 17. UNC Greensboro 5th April 2013  Upavon, Salisbury Plain, UK - Mission (Almost) Impossible 4th March 2010 - Natural Environment Research Council, Airborne Remote Survey Facility - Lidar and spectral bespoke data acquisition Earth Resistance Survey Ground Penetrating Radar Spectral survey Soil Samples Topography Survey All contemporary to the flight
  18. 18. UNC Greensboro 5th April 2013 Spectral Data Lidar Data Impact of Visualisation TechniquesVegetation Indices Feature Profile Analysis Seasonal Comparison Digital Data Stack Land useAssessment
  19. 19. UNC Greensboro 5th April 2013   Existing Visualization Methods  Airborne Laser Scanning 1. Slope, aspect, curvature 2. Shaded relief modeling 3. Principle Components Analysis 4. Horizon modeling (Sky View Factor) 5. Local Relief ModelingBennett, R., Welham, K., Hill, R.A., Ford, A., 2012. A Comparison of Visualization Techniques for Models Created from Airborne Laser Scanned Data. Archaeol. Prospect. 19, 41–48.
  20. 20. UNC Greensboro 5th April 2013Bennett, R, K Welham, R A Hill, and A Ford. 2013. ‘Using Lidar as Part of a Multisensor Approach toArchaeological Survey and Interpretation’. In Interpreting Archaeological Topography – Airborne Laser Scanning,Aerial Photographs and Ground Observation, ed. D C Cowley and R Opitz, 198–205. Oxford: Oxbow Books.
  21. 21. UNC Greensboro 5th April 2013
  22. 22. UNC Greensboro 5th April 2013   Existing Visualization Methods Airborne Spectral data 1. Individual bands 2. True and False Color composites 3. Principle Components Analysis 4. Vegetation Indices 5. Spectral SeparabilityBennett, R., Welham, K., Hill, R.A., Ford, A.L.J., 2012b. The Application of Vegetation Indices for the Prospection of Archaeological Features in Grass-dominated Environments. Archaeol. Prospect. 19, 209–218.
  23. 23. UNC Greensboro 5th April 2013
  24. 24. UNC Greensboro 5th April 2013
  25. 25. UNC Greensboro 5th April 2013Comparison of Sensors
  26. 26. UNC Greensboro 5th April 2013The traditional view: aerial imagery 2002 2004
  27. 27. UNC Greensboro 5th April 2013 Seeing More...Airborne Laser Scanner (ALS): Hyperspectral sensor: topographical features Proxy soil and vegetation change
  28. 28. UNC Greensboro 5th April 2013 Summary of findings  • Archive airborne lidar and spectral data can be used to identify features in non-arable environments• NIR region highly sensitive to vegetation change representing archaeological features in both January and May• More features seen in January than May, indicating that for environments where vegetation is less prone to stress (i.e. cropmark formation) off-season data collection may be of equal or greater value to peak-season data• Suite of visualization methods, assessed quantitatively to provide a toolkit for the use of ARS data for archaeological prospection• High complementarity of the sensors
  29. 29. UNC Greensboro 5th April 2013 Research and Teaching at DukeAirborne Remote Sensing of Exmoor National Park 3D Interactive environments for exploring ARS
  30. 30. UNC Greensboro 5th April 2013 Desk based assessment of lidar, historic maps and aerial photographyGIS Feature Records Features assessed during fieldwork
  31. 31. UNC Greensboro 5th April 20133D Interactive Environments Exploration, Education and Outreach Immersive Duke DiVE Web-based open-GL module
  32. 32. UNC Greensboro 5th April 2013 Thank you for listening!For the PhD research thanks are also due to… The Ministry of Defence and Defence Estates for facilitating access, especially Richard Osgood & Martin Brown, Senior Historic Environment Advisors & Chris Waldren and Chris Maple DE Geospatial Services Wiltshire HER and Roy Canham NERC ARSF, FSF and GEF for data and equipment loans The Superstar Field Team: Dr Kayt Armstrong, James ABCD Bennett, Barney.B.Bennett, Kimberly Briscoe, Roy Canham, Justine Cordingley, Katie Hess, Kuro Kuma Hess, Heather Papworth, Matthew Sumnall, Rachel Stacey, Kate Ward, Matthew Webster and Sarah Yarnall This research was supported by a Bournemouth University Doctoral Research BursaryFor the postdoc research thanks are also due to… Exmoor National Park Authority, especially Rob Wilson-North, Lee Bray and Catherine Dove The Wired! Lab The David.L.Paletz Innovative Teaching Fund The Exmoor Student Field Team: Nathan Bellis, Jordan Noyes, Lindsey Mazurek, Kelsey Richards, Crystal Terry