From left to right: Francisco Gonçalves, president director of Southeast Asia operations for McElhanney; Tann Bou Suy, deputy director general, APSARA Authority; Dr Ea Darith, deputy director, Department of Conservation of the Monuments outside the Angkor Park; Dr Damian Evans, project coordinator, University of Sydney. Photograph: Nicky Sullivan/Phnom Penh Post
A consortium including the Apsara Authority, University of Sydney, the Ecole Français d’Extrême Orient, and five other partners, is waiting excitedly for the results of a three-dimensional topographical survey of the Angkor Conservation Park and sites at Koh Ker and Phnom Kulen.
The survey was conducted using a light detecting and ranging machine (Lidar) strapped to a helicopter that spent 20 hours in the air flying in a grid over the target sites. It is the first survey like this performed in Southeast Asia, and the largest carried out in the world.
According to the project coordinator, Dr Damian Evans from the University of Sydney, the data that will come back from the survey would have taken a lifetime to acquire using traditional methods, and as a result archaeologists will have an immensely improved understanding of the site.
Flying one kilometre up in the sky and using laser technology, the machine is able to “see through” forest cover and overcome other hurdles.
Evans said, “This means that in areas like Phnom Kulen and Koh Ker, which remain heavily mined and densely forested, we can create very precise and very detailed archaeological maps for the first time, looking particularly at things like canals, dams, urban enclosures and these kinds of features.
“For each square metre of the landscape we get upwards of a dozen height measurements, with in-credible precision down to centimetre level. These kinds of measurements are incredibly important because we use subtle variations in surface topography to identify the traces of the urban fabric of Angkor – roadways, canals, occupation mounds, village temples, and so on.
“These things have long disappeared and are often buried just beneath the ground, but all of them leave very subtle traces in the surface of the landscape, even a thousand years later. The Lidar data will help us to identify and map those traces with great precision, even where they are completely overgrown with jungle.”
The survey method is so precise that it generated 3D profiles of the people walking around Angkor Wat, and can tell if the people were standing still, walking, or pointing.
The project itself had its own hurdles to overcome, including negotiating exemptions for the importation of a US$2 million machine, and authorisations for flying over Angkor, which is technically a no-fly zone.
The information generated by the survey will not just help to understand the structure of Angkor, but also how it was managed.
Evans said, “These days, most archaeologists acknowledge that the success of the Angkorian civilisation was intricately tied to their ability to effectively manage water. Having this very precise elevation data allows us not only to identify where dams, canals and reservoirs were located at places like Koh Ker, but also how they functioned, if they functioned effectively, and so on.”
The data will also help with management of the site today. Im Sok Rithy, the head of the Land Department at the Apsara Authority, is looking forward to seeing the results.
He said, “The new information is very important for the management and development of the area as well as understanding the history. For example, we hope that we can use the data to help us prevent the kind of flooding that we saw last year from happening again.”
The consortium is expecting the results at the end of May. The consortium also includes the World Monuments Fund, Japan-Apsara Safeguarding Angkor, The Archaeology and Development Foundation Kulen, Hunincor Ltd (Hungary), and the Société Concessionaire d’Aéroport (SCA) / Institut National de Recherches Archéologiques Préventives (Inrap) team.
