cultural-heritage
„We’re making time visible“
Nicola Lercari investigates
historical sites
with state-of-the-art
remote sensing methods.
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Its six rotors gently whirring, the powerful drone is poised on the Sicilian beach of Heloros like a giant insect. The strong winds of the past few days, which made its launch impossible, have subsided. It is seven in the morning, too early for tourists. And so Nicola Lercari can finally launch the reconnaissance flight over the 2,800-year-old ancient Greek city which once stood on the cliffs above the beach.
The city was once home to several thousand people.
Only a few remnants of Heloros can be seen today: a portion of the city walls, the foundations of a few temples, the remains of the market square (agora), and a badly damaged theater. The city was once home to several thousand people and held a prominent role in the Greek colonization of Southeastern Sicily. “Most structures are still hidden underground,” says Lercari. This includes large sections of the old city walls, various residential neighborhoods, and the traces of roads leading to surrounding areas and all the way to Syracuse 30 kilometers away. The first settlement built by the Corinthian Greeks on the island, Syracuse was the largest city in the region and lay at the center of a dozen or so satellite towns (subcolonies) such as Heloros.
After all the waiting, the LMU researcher’s high-tech drone can take off and start its job of searching from the air. Equipped with a high-resolution camera, an infrared sensor, a lidar sensor (which uses laser light to scan the surface of the ground below), and all manner of precision electronics, the newly purchased device hovers above the hilly Sicilian country, 50 meters in the air, held exactly in position by means of GPS navigation. “Even during windy conditions, the drone is very stable in its flight,” says Lercari. This is crucial for the quality of the lidar data.
State-of-the-art remote sensing methods are at the heart of Lercari’s work. They provide him and his team with an overview of the terrain, as here in Heloros. “Researchers used to trek through the jungle or other inhospitable regions for months to find ruins. Now, we fly an aircraft equipped with LiDAR – or indeed our very own drone – for a day and find the heritage sites later in the lab,” says Lercari.
Prof. Nicola Lercari
heads the Institute for Digital Cultural Heritage Studies at LMU, which he established as its chair.
Born in 1982, Lercari studied communications at the University of Genoa and film and media production at the University of Bologna, going on to complete his doctorate in history and computing at the latter. At Duke University he worked as a postdoctoral researcher. At the University of California, Merced, he worked as a postdoc at the Department of Humanities and World Cultures, and then as an assistant professor in the Department of Anthropology and Heritage Studies, and finally as associate professor of heritage studies, before coming to LMU in 2022.
12 missions, 3 square kilometers (km2), 3D buildings
This gives archeologists brand new possibilities for surveying ancient cultural sites over a wide area – in some cases, recording them for posterity before their destruction through war, natural disasters, and erosion. It is Lercari’s mission to exploit these opportunities. The data he obtains, which is processed using computer programs and analyzed by skilled archaeologists, can help solve mysteries from the past, understand places and their stories, and protect these ruined sites from further decay and ultimate oblivion.
Preserving places from oblivion
In a week-long campaign, Lercari and the Heloros Advanced Digital Exploration and Surveying (HADES) project team flew twelve missions over Heloros’ landscape, scanning over three square kilometers of terrain, which is roughly equivalent to four hundred twenty soccer pitches. During the flyovers, the high-tech devices on board recorded the terrain below, lodging high-resolution imagery and billions of measuring points in the memories of the instruments. In this way, a landscape with 3D structures and topography is progressively built up in the computer in the course of a site survey. Each measuring point is furnished with exact geodata. To this end, the drone must not only be held in position in windy conditions, but the geolocation data also has to be captured in real time.
With millimeter precision, Lercari and his team scanned the ruins and urban structures, even capturing details concealed in the dense undergrowth of the southern Italian macchia. “We didn’t know whether the instruments would penetrate the dense network of shrubs,” recalls the Chair of Digital Cultural Heritage Studies at LMU with a smile. “But they did so with aplomb. We were even able to scan parts of the seafloor in the shallow water zone on the coast, something previous lidar survey carried on from airplanes flying at higher altitude did not manage to do.”
Potentially, the new data about the Heloros’ coastline and adjacent marshes could help researchers find the as-yet-undiscovered ancient harbor. This would be no mean feat, as the coastline has changed substantially over the past 2,800 years. On land, Lercari’s team discovered traces of the ancient cart tracks made by carts going over the same route for centuries that can shed new light on the road network along which Greek goods were transported. The team also mapped in 3D with high precision the large quarries that furnished the materials for construction work in the city.
If we were to discover the original path of the ‘Helorine way’ or the road to Syracuse, that would be a wonderful exploit!
During its Hellenistic phase, Heloros clearly had impressive ramparts, an imposing northern gate, a large theater, and several temples. Overall, it bears the hallmarks of a unique urban planning, which is quite different from other Greek settlements in Sicily. In building up a detailed picture of the city and its connections to its hinterland, the new technologies can provide impetus for fresh interpretations.
“If we were to discover the original path of the ‘Helorine way’ or the road to Syracuse, that would be a wonderful exploit,” says Lercari. He is interested in showing how the city developed over the course of time: “We’re making time visible.” His dream is to open up the as yet scarcely excavated city to tourists one day.
Data collected on the fly – no digging required
What makes Lercari’s results unique is the level of precision in the information they provide about ancient cultural sites, all collected from the air at an unprecedented speed and scale. “The precision of the data is a game-changer,” says Lercari. “It allows historical sites to be documented in 3D with millimeter accuracy, such that we can preserve them in digital form for future generations or archaeological features to be identified in the landscape with no digging required.”
Now we can evaluate the data pretty much in real time.
To pursue just such tasks, Lercari has established the Institute for Digital Cultural Heritage Studies at LMU. New visualization methods and automated techniques allow researchers to discover correlations in the data between individual buildings and their environment – something previously outside the reach of archeological methods. Technological advances in drone and lidar technology also bring huge advantages during operations on site: “Now we can evaluate the data pretty much in real time,” says Lercari. “If we find an interesting structure or anomaly in the data we scanned in the morning, we can go back the same day and immediately check what is concealed from our view, whereas we used to have to wait for months for the lidar data to processed and analyzed.”
The HADES project is something of a model in this regard, exhausting all the possibilities of digital data acquisition and digital exploration. Furthermore, it is designed to demonstrate how helpful such data can be in understanding a forgotten city and its history.
Video
The past, 3D scanned
The oldest settlement in human history
Lercari tells of his academic origins at the University of Bologna, where he started out at the Department of History and Cultures. Intrigued by the connections between history and computing, he studied the history of the city of Bologna using digital methods. In collaboration with computer scientists and visualization specialist working at the CINECA supercomputing center he sought to develop a technique for virtually reconstructing and creating 3D visualizations of the medieval city with its numerous 13th-century towers.
His desire to work at the interface of archeology, museology, and IT took him to Duke University and then to the University of California, Merced in the United States, where he remained until he took up an appointment as Chair of Digital Cultural Heritage Studies at LMU. Over this period, he became increasingly interested in how we can better investigate and conserve our cultural heritage in the digital age using digital tools.
A sort of social memory
During this period, Lercari undertook a large digital data capture and 3D visualization project at the Neolithic site of Çatalhöyük in Turkey, one of the oldest and best preserved settlements in human history. The site is critical for our understanding of early agricultural societies in the Near East and questions of sedentism. Lercari’s work focused chiefly on investigating the repeated use of space over the centuries through the construction of overlaying houses and how to represent visually this kind of social memory. For him, it was about expanding the very concept of excavation – “We used to call it 3D excavation,” says Lercari.
His team used digital imaging and laser scanning technologies to record the rooms of the houses in the settlement and then visually enriched them with additional information so that they could interpret them better. “Even before the term Digital Humanities became widely adopted , I was calling myself a humanist computer scientist ; now I’d describe myself as more of a digital heritage specialist,” he says. Although immersed in the development of new research techniques, he always had a keen eye for the human dimension, striving to understand the lives of the ancient inhabitants of the Neolithic settlement, their rituals, and how their households functioned.
A chat with Nicola Lercari quickly turns into a voyage through the cultural history of the Earth. He has the freedom to explore cultures and regions throughout the ages, says Lercari, unlike many archeologists, who are specialized in one region or period. The Italian scientist has done work across the globe through partnership with world-class universities such as Stanford, the National Autonomous University of Mexico, and the University of South Florida: He has worked in the famous Mayan city of Palenque, the ruins of which he searched for in the Mexican jungle and where he surveyed palaces, temples, and homes. He has worked at Çatalhöyük, Turkey as described above and has investigated important historic sites in California, such as Bodie and Fort Ross. And now he is working in Sicily, where he is investigating the early settlement history of the Corinthian settlers and how they slowly gained a foothold far from their homeland.
Remains of a medieval metropolis
His niche within archeology has gained a boost in recent years as a result of spectacular lidar images of lost jungle cities and temples taken from the air – at the Cambodian temple complex of Angkor Wat, for example, just outside of which researchers discovered the remains of a vast medieval metropolis hidden beneath the forest around ten years ago.
At Palenque in Mexico, Lercari managed to identify hidden buildings and structures in the jungle and determine their function. “We discovered canals there that supplied Palenque farms with water,” recounts Lercari. “It was once a big city with sophisticated water and urban infrastructure.”
It was once a big city with sophisticated water and urban infrastructure.
There remain many questions to clarify there, he observes, such as how different districts of the city contributed to urban life and whether the elites who lived near the royal palaces benefited from this proximity. The perfecting of these techniques has significantly advanced classical scholarship in its ability to answer important questions.
A matter of overview
The methods allow large areas of land to be scanned precisely from the air in rich detail, at much lower cost and effort than conventional approaches. Firstly, researchers no longer have to slog through unforgiving terrain for months on end thanks to the ability of lidar to penetrate the tree canopy or shrubs (the wavelength of the light used is not absorbed by the leaves). And secondly, Lercari’s data makes it possible to answer questions which sometimes need an overview – which is to say, a view from above.
The data scans of the terrain recorded during the flyovers are converted into 3D images of terrain, ruins and urban structures. They help not only to make new discoveries, but they can also be so precise, vivid, and surprising that they, as Lercari puts it, “breathe new life into old sites.”
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