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Digital Methods for Documenting Cemeteries

Chad Keller

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Digital Methods for Documenting Cemeteries

  1. 1. Non Invasive Techniques for Documenting Historic Cemeteries Structure from Motion, Colonial CemeteryLaser Scanning , Laurel Grove Cemetery
  2. 2. Laser Scanning  Faro Focus 3D  Phase-based scanner  40 million points in 10 minutes  Accuracy within 1/8th of an inch  On board camera Yuen Mansion ca. 1920, Lantau Island, Hong Kong
  3. 3. Laser Scanning
  4. 4. Laser Scanning  Laser scanning involves three- dimensional point capture.  The points are oriented in a point cloud and are a representation of three-dimensional space. Historically Black Cemetery, Grove Point Plantation
  5. 5. Laser Scanning  Approximately 30%-50% overlap required between scans  Multiple scans are unorganized until they are registered St. Helena Chapel of Ease ca.1740
  6. 6. Laser Scanning Manual Registration Manual registration involves manually identifying points between scans. Automatic Registration The software automatically registers the scans using targets that are placed around the site. Barboursville ca. 1822 destroyed 1884 , designed by Thomas Jefferson, Barboursville, VA
  7. 7. Manual Scan Registration  Scan Registration  High Resolution
  8. 8. Laser Scanning  Create two-dimensional drawings  Three-dimensional CAD models CAD drawings of Lot 988, Laurel Grove Cemetery
  9. 9. Structure from Motion  Based on photogrammetric principles, but creates a three-dimensional model from two-dimensional images.  Point and shoot camera  Density of point cloud dependent on the size of the images Historically Black Cemetery, Grove Point Plantation
  10. 10. Structure from Motion Point cloud and image locations
  11. 11. Structure from Motion Polygonal mesh
  12. 12. Structure from Motion Photo textured model
  13. 13. Laser Scanning vs. Structure from Motion Laser Scanning Photogrammetry Pros Pros •Accuracy within ¼ of an inch for most scanners •Accuracy over large spaces •Captured at true scale •Significantly cheaper equipment •Better visual representation of textures Cons Cons •Equipment can be prohibitively expensive to own •Generally need to upgrade physical equipment to keep up with progress •Accuracy is lower than laser scanners over large space •Scale limitations based on camera lenses maintaining clarity over long distance
  14. 14. Wild Heron and Grove Point Google Maps
  15. 15. Wild Heron and Grove Point Rice mill ruins Irrigation channel
  16. 16. Wild Heron Marked graves
  17. 17. Wild Heron Grave depression
  18. 18. Wild Heron Numbered flag
  19. 19. Wild Heron Marking depressions
  20. 20. Wild Heron Recording with total station
  21. 21. Wild Heron Depressions plotted in Autocad
  22. 22. Wild Heron Depressions recorded in ArcMap
  23. 23. Grove Point Well-maintained and still in use
  24. 24. Grove Point Grave markers
  25. 25. Grove Point Well-maintained and still in use
  26. 26. Grove Point Structure from MotionLaser Scanning
  27. 27. Grove Point Registered point cloud
  28. 28. Grove Point Markers georeferenced in ArcMap  Georgia Individual marker survey form