After a major earthquake rocked Mexico City in 2017, the authorities wanted to assess the damage it had caused to the city’s cathedral, the largest and arguably most spectacular building of its kind in Latin America.
Rather than have to rely on ladders and winches like its 16th-century builders, they could call on technology for answers. US-based digital scanning experts were invited to survey and digitally record parts of the cathedral, including the retablo dos reyes, the spectacular gilded screen that stands behind the high altar, allowing the cathedral’s restoration team to inspect it for cracks or other damage.
That digital scan, captured by cameras at ground level and attached to drones, is released online today alongside 17 other interactive models of at-risk heritage sites around the world, illustrating what its developers say will become an increasingly important tool in the recording and preserving our global cultural heritage.
In a week in which one of the world’s most beloved heritage sites was narrowly saved from burning to the ground, the technique “can provide tremendous value in the event of an unanticipated event such as the fire at Notre Dame”, according to John Ristevski, chairman and CEO of CyArk, the non-profit organisation which captured the digital models.
Notre Dame, he pointed out, was digitally scanned some years ago by a team from Vassar and Columbia universities, which some believe could be “terribly important” in its reconstruction.
Released in partnership with Google’s Arts and Culture platform, the new models and the data behind them can be examined and downloaded by academics, engineers, VR developers or teachers, but can also be explored by anyone who is intrigued by heritage at risk – or who simply wants to virtually zoom around a Greek temple to Apollo, inside a medieval Syrian hospital or across the roof of the Jefferson memorial in Washington DC.
Ristevski said: “The digital scans provide a very accurate 3D surface model of the entire structure that can be used to create engineering drawings that can assist in the physical reconstruction of the monument by ensuring that intricate details and characteristics are preserved.”
The new scans, which join several dozen other sites previously released on the Open Heritage portal, capture structures which are happily still standing, but in each case they were created to capture a snapshot of a building which may be at risk, Ristevski said.
In the years since its founding in 2001 the organisation has documented more than 200 sites around the world, he said, in partnership with the authorities responsible for their upkeep. “We have been sitting on this treasure trove, and we didn’t have a great way to open it up and share it with the public.” Releasing them online “seemed like a great opportunity to give it a public face”.
“Most cultural heritage is very complex in three dimensions, and trying to distil that down to simple drawings is very, very difficult,” he said. “So this brings a whole new way of doing it.”
The technology also allows access to sites which may be off-limits to archaeologists. Among the newly released digital scans are a number captured at sites in Syria, which were made by local engineers and architects who had been given tools and training by CyArk.
In stark contrast to the baroque bombast of Mexico City’s cathedral, the Syrian sites include the small, early Christian chapel of Ananias in Damascus, on a site reputed to be the home of a man whom the Bible says baptised St Paul.
Though the church, unlike much of Syria’s heritage, has escaped damage in the civil war, it was recently flooded, and a scan was produced to act as a “baseline” should further damage occur.
The two organisations have formed the Open Heritage Alliance with the University of South Florida, which is monitoring Nasa launch complexes at Cape Canaveral, and Historic Environment Scotland, which has previously captured digital scans of a number of neolithic sites on Orkney, and they expect others will join them in releasing digital models online, said Ristevski.
“All these data sets are collected at great expense, they get used once and then are locked away. But someone could turn this into a 3D print or a VR experience, there are so many reuse cases we could give life to if we could just find a way to share [the data].”
