1. Recording Petroglyphs
Dr Jim Chandler, Loughborough University, UK
Prof. John Fryer, University of Newcastle, NSW, Australia

2. The problem Yengo National Park, NSW
Inaccesssible, numerous- need recording before weathering/vandalism

3. Raw imagery
“dry”
“wet”

4. Digital camera sensors
Any digital camera with 5 Megapixels or more will do the job!
Probably can use your phone camera in a year or two!

5. Image acquisition

6. Control requirements
Either:
Simple scale bar
Targets

7. Photogrammetry Process
We used Imagine/OrthoBase/LPS
Cost- AU$ 28,000
New Products coming onto the market are much cheaper
Still fairly complex to use

8. Photogrammetry
Generation of the Digital Elevation Model (DEM) … this is the 3-D shape of the ground
Use this shape to ‘correct’ the images so they represent a true flat plan of the surface
Enhance (deepen) the grooves and fit the corrected image over them

9. Data products- DEM Big Fella DEM Initially, limited value!?
Slope shading helps?

10. Image processing reveals data!
Erdas “Spatial Model” tool
Now we can see it!

11. Accuracies? +/- 2mm DEM measured using reflectorless Total Station
Difference DEM: Nikon - TStation
Cross-section
Eyes

12. Visualisation (1)
DEM
Different lighting
Draped ortho- “dry”
“Wet”

13. Visualisation (2)
Fly through movie

14. j.h.chandler@lboro.ac.uk http://www-staff.lboro.ac.uk/~cvjhc/index.htm
Conclusion
Publication put into Rock Art Research
Where to next?