The deliberate destruction of Palmyra by ISIL in 2015 has obliterated several of its major monuments. But work is afoot to preserve Palmyra’s monuments – in virtual form.
Palmyra Photogrammetry is an ambitious one-person initiative from archaeological geometrician Conan Parsons. Conan aims to create a 3D model of the lost monuments of the ancient city.
History and Archaeology Online spoke to Conan to discover what inspired him to undertake such an ambitious project, how he is proceeding– and how people can help.
Palmyra Photogrammetry
Conan Parsons set up Palmyra photogrammetry on August 22 2015, in response to the destruction of the temple of Bel Shamin.
Conan was already familiar with photogrammetry from his work for a commercial archaeology company in the UK, where he generated 3D models of archaeological structures for clients unable to attend site meetings.
But it was the work of Project Mosul, an initiative set up by researchers of the Initial Training Network for Digital Cultural Heritage that inspired him to put his skills to use in Palmyra.
“I was inspired by Project Mosul, after seeing in the news their work on reconstructing artefacts that were destroyed in Mosul Museum by Islamic State,” Conan told History and Archaeology Online.
“Working as an archaeological geometrician, I thought, ‘I’m doing this for entire sites at work; if I can ask the public for their photos, then maybe I can do the same on a larger scale’ “
What is Photogrammetry?
Photogrammetry is roughly defined as the science of making measurements from photographs– usually for maps, drawings– or 3D models for individual objects.
“Originally, it was intended for use on specific objects, but it also works for larger subjects, too,” explained Conan.
The pictures used in photogrammetry can either be aerial or close range. For the purposes of his project, Conan has requested close-range photographs from visitors to the site.
But how do photographs recreate actual objects?
“When there are enough photos covering all angles of the subject, a point cloud (A set of 3D data points defined by X, Y, and Z coordinates) is created from the aligned photos,” explained Conan. “Using the metadata from the digital photos (such as ISO, shutter speed, aperture etc.), distances are estimated.”
The more photographs used, the better:
“As more photos are aligned, these estimations become more accurate,” Conan continued. “Angles and shapes are then calculated from these measurements. Once the photos are all aligned, and camera positions checked for accuracy, unwanted objects (such as people, tools, detritus) a dense cloud is created as the next step, giving a good representation as to how the model will appear.”
This point cloud creates the barebones of the model using a computerised wireframe mesh as the basic form of the object in question. The model is then checked to see if it’s the correct shape, and, if necessary, the coordinates are also double-checked to eradicate any errors.
“Finally,” said Conan, “the photos are used again to create one large image, which is then overlain on the mesh to create the final model.”
Progress to Date
To date, members of the public have donated over 3000 pictures to the project, which Conan has used to begin work on recreating the monumental arch, the tetrapylon and the theatre.
Other donors include Agisoft, who provided the project with a free license for the software Conan uses for his models. His employer, Oxford Archaeology, has also helped, loaning a laptop and secondary monitor to use until crowdfunding for his own hardware is complete.
“Originally, I hadn’t intended to crowdfund anything!” said Conan. “But I tried running a ‘quick’ test of an area and quickly realised how out-of-date my laptop had become.”
International Interest
There has been worldwide support for Conan’s project. Professor Meyer of Begen University became the project’s largest donor, gifting 8GB of the photos to date and providing a map to help Conan scale and orient the models.
Project Mosul, Conan’s initial inspiration for the project, also became involved. In addition, British archaeological societies such as BAJR and Modern Conflict Archaeology have thrown their weight behind the project in the form of social media support.
Conan’s work has also proven inspirational for others.
“I have had enquiries from PhD students who are writing papers that touch upon 3D reconstruction or conflict archaeology,” said Conan in 2015. He was also asked to write an article about his work for Rescue News. “Also, I have been approached by Erin Thompson, Assistant Professor of Art Crime at John Jay College of Criminal Justice, he explained.”
Palmyra in 3D
“The ultimate outcome would be a complete representation of the site in 3D,” Conan said,” but using tourist photos, this is highly unlikely to be achieved. However, I am confident that individual buildings such as the Temples of Bel and Baal Shamin, the amphitheatre and tetrapylon, etc., will be recreated in their relative positions and gaps can be filled by other methods.”
The Palmyra project has also whet his appetite for future challenges.
“When I have done as much as I can, I can use then use the equipment on another project or otherwise help out project Mosul,” he explained.
In the meantime, Conan still needs as many photographs as possible taken from many different angles to recreate Palmyra’s buildings as accurately as possible.
Can you help? If you have any digital photographs of Palmyra, please email palmyra3dmodel@outlook.com and see their Facebook page for more details.
Resources
Vincent, Matthew. Project Mosul. (2015). Project Mosul. Accessed on November 18, 2015
Palmyra Photogrammetry. Palmyra Photogrammetry. (2015). Accessed on November 18, 2015
Photogrammetry. What is Photogrammetry? (2007). Accessed on November 18, 2015
Heritage Together. How Photogrammetry Works. (2015). Accessed on November 18, 2015
