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Digital Recording & Community ArchaeologySt. Canice’s Graveyard, Finglas
Date of survey: Sept. 2011
Ruth Johnson, Dublin City ArchaeologistAndrea Acinelli, Survey & Mapping Division (DCC)
John Tierney, Eachtra Archaeology Ltd. (Historic Graves Ireland)
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2013, Dublin
Digital Recordingof the “Nethercross”
St. Canice’s Graveyard, Finglas
Date of survey: Sept. 2011
Ruth Johnson, Dublin City ArchaeologistAndrea Acinelli, Survey & Mapping Division (DCC)
ArcLandConference
2013, Dublin
Location map showing Finglas and Tallaght, the “two eyes of Ireland”.ArcLand
Conference2013, Dublin
Finglas
Tallaght
City Centre
Osi Barony map from 1886 showing the Baronies of Nethercrosss and Uppecross.ArcLand
Conference2013, Dublin
Nethercross
uppercross
Map of Finglas Village (1869) showing location of High Cross and ortho image (2008) showing modern context.
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2013, Dublin
N2 National Road
High Cross
St. Canice’s Graveyard
St. Canice’s Graveyard
High Cross
Historic photo ( early 20th Century) and antiquarian sketch (19th Century)ArcLand
Conference2013, Dublin
Finglas Heritage Trail
Designed by Yellowstone for DCCArcLandConference
2013, Dublin
ArcLandConference
2013, Dublin
Finglas Heritage Trail
Designed by Yellowstone for DCC
ArcLandConference
2013, Dublin
Why? (1)
Accurate & complete digital record of the geometric information to use for:
• Art historical analysis andarchaeological analysis
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2013, Dublin
Why? (1)
Laser
Nakedeye
Scanning
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2013, Dublin
Accurate & complete digital record of the geometric information to use for:
• Condition monitoring• Raising awareness - community & education• Multimedia publication• Other
…. Because now we can!
Why? (2)
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2013, Dublin
How?
In 2011 Survey & Mapping Division (DCC) evaluated and recognized the benefits for introducing remote
sensing technologies:
Acquired a Phase-Shift Laser Scanner (Faro 3D)
Developed technical skills
Upgraded hardware
Improved network storage and communication
…... a time consuming process!!
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Spatial information from different 3D Acquisition Systems
3D Model
Range-Based
Reality-Based
Image-Based
GPS
Total Station
Lidar
Laser Scanner
Satellite Imagery
Arial Photogrammetry
Close-Range Photogrammetry
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Data collection (1)
1 Day field work (sunny day!!)
Equipment:
Faro 3D laser scanner (hired)
Trimble 5800 GPS receiver
Trimble S8 total station
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2013, Dublin
Data collection (2)
Laser scanning survey:
9 scan stations (2.5m to 5m from the cross)
10 reference objects: 7 spheres and 3 flat targets
Scans details:
Scans resolution 3mm
Overlap between scans 40-50% (final res. 0.5 – 1.5mm)
Over 9GB of data collected & …... “millions” of points
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2013, Dublin
Data collection (3)
STN1
STN2
1-2
3-4
5-6
7-8
9
Survey stations
Scanner positions
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Data Processing (1)
Manual recognition of all targets was very quick & reliable
Scans registration using “Scene” software (by Faro)
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Data Processing (2)
• Segmentation• Noise reduction • Outliers removal• Decimation • Merging
MeshLabOpen Source Software
Point cloud pre-processing
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Data Processing (3)
• Vertex normals are computed• Very dense point cloud• Object completely covered
MeshLabOpen Source Software
Poisson Surface reconstruction
It works very well if:
It create a closed and water-tight surface.
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Data VisualizationBasic visualization methods
MeshLabOpen Source Software
Points
Wireframe
Shaded
Shaded
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Data Visualization MeshLabOpen Source SoftwareTools for enhancing surface shading
Ambient Occlusion
Mean Curvature
ZBrush
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2013, Dublin
Thank you!
