Remotely sensed data and imagery have revolutionized the way we understand archaeological sites and landscapes. LiDAR / airborne laser scanning (ALS) has been used to capture the often subtle topographic remnants of previously undiscovered sites even in intensely studied landscapes, and is rapidly becoming a key technology in survey projects with large extents and/or difficult terrain. This paper examines the practical application of this technology to archaeological heritage management, with special attention given to how ALS can support the World Heritage List nomination process and management of WHS archaeological sites and landscapes. It presents a number of examples from published ALS studies alongside case studies from projects undertaken by the authors at Cultural Site Research and Management and the Cultural Site Research and Management Foundation, Baltimore, Maryland, USA. The paper opens with a review of how ALS has been used at established World Heritage Sites, focusing on the Archaeological Ensemble of the Bend in the Boyne, Ireland, and the Angkor Archaeological Site in Cambodia. ALS applications for site prospection and demarcation, and viewshed analysis is explored in this section. Following this, we explore how ALS has been used to support two recent applications: the successfully nominated Monumental Earthworks at Poverty Point, USA and the recently nominated Orheiul Vechi Archaeological Landscape in Moldova. We propose that the detail offered by ALS data greatly strengthens nomination dossiers by emphasizing the outstanding universal value of sites, highlighting significant features and providing greater context to wider landscapes, and is particularly efficacious in delineating site boundaries for legal protection and long-term management. Finally, we conclude with a look at some of the practical considerations involved in the use of ALS, including access and training.
If anyone is in Singapore tomorrow, catch Dr Kyle Latinis’ talk at ISEAS
LiDAR (Light Detection and Ranging) is one of the newest remote sensing technologies to be used for archaeology and related sciences. Results are revolutionizing the field, especially among researchers studying ancient urban landscapes in Southeast Asia (The Guardian, 11 June 2016).
LiDAR applications digitally peel away forest canopies and vegetative cover resulting in sophisticated surface images and detailed topographic maps of natural and cultural landscapes. LiDAR data has been integral for recent research and training initiatives at the Nalanda–Sriwijaya Centre (NSC).
LiDAR abilities cannot be underestimated. However, there are limitations. Ground-truthing through archaeological surveys and excavations continue to play necessary and central roles.
The following discussion will introduce LiDAR technology, capabilities, and limits followed by examples of LiDAR application for two recent NSC projects: Mahendraparvata – the 9th century Angkorian capital city of Jayavarman II, legendary founder of the Angkorian empire; and Koh Ker [Chok Gargyar] – the mysterious 10th century Angkorian capital city of Jayavarman IV, often depicted as a rogue usurper king. Future NSC research possibilities using LiDAR applications for other Southeast Asia sites will also be introduced.
Be prepared to sweat. Exploring the world’s largest religious complex in the Cambodian jungle is not for those who can’t take the heat. The sheer size of the gigantic edifices of Angkor Wat and the distances between them means long treks, in 40-degree heat and humidity as if in a sauna.
But then, what you get to see is stunningly unique. There are the monument-sized sandstone buildings, delicate carved bas-reliefs, and the strangler figs, huge snake-like plants creeping up the walls and buildings as if to swallow them up. Like in some enchanted forest.
It is almost impossible to believe that more than 800 years ago, in the heyday of the Khmer culture, hundreds of thousands of people lived in this merciless jungle setting.
But what archaeologist Damian Evans has now uncovered with the help of an airborne laser measurement technology called Lidar (light detection and ranging) explodes everything that was known heretofore.
A new paper in the Journal of Archaeological Science has been grabbing the headlines in the last few days: the first insights from the Lidar acquisition of Angkor. It is the most extensive use of Lidar in an archaeological context to date, which brings to greater clarity the urban sprawl of Phnom Kulen, Banteay Chhmar, the Preah Khan of Kompong Svay, Sambor Prei Kuk, Longvek and Oudong. Combined with the earlier acquisition of the core Angkor area in 2012, the Lidar data has uncovered a tremendous amount of information about settlement patterns in these areas.
The data gathered presents a big-picture view of several themes of interest: population flows, urban centres, water management and collapse, and provides starting points for many of these future lines of inquiry. To be sure, the patterns in landscape and features uncovered by the Lidar is spectacular, but many of these features will need to be ‘ground-truthed’ and investigated in real life. (Alison has a good commentary about the potentials and limitations of the Lidar data). All in all, a very exciting start to what is surely a new phase of archaeological understanding of Angkor, and hopefully one with repercussions to the rest of the region as well!
Early Khmer societies developed extensive settlement complexes that were largely made of non-durable materials. These fragile urban areas perished many centuries ago, and thus a century and a half of scholarly research has focussed on the more durable components of Khmer culture, in particular the famous temples and the texts and works of art that are normally found within them. In recent years however there has been a considerable effort to broaden the perspective beyond conventional approaches to Khmer history and archaeology. Remarkable advances have been made in the domain of remote sensing and archaeological mapping, including the application of advanced geospatial techniques such as airborne laser scanning within studies of heritage landscapes at Angkor and beyond. This article describes the most recent applications of the technology in Cambodia, including the results of a newly-completed campaign of airborne laser scanning in 2015—the most extensive acquisition ever undertaken by an archaeological project—and underscores the importance of using these methods as part of a problem-oriented research program that speaks to broader issues within history and archaeology.
Archaeologists in Cambodia have found multiple, previously undocumented medieval cities not far from the ancient temple city of Angkor Wat, the Guardian can reveal, in groundbreaking discoveries that promise to upend key assumptions about south-east Asia’s history.
The Australian archaeologist Dr Damian Evans, whose findings will be published in the Journal of Archaeological Science on Monday, will announce that cutting-edge airborne laser scanning technology has revealed multiple cities between 900 and 1,400 years old beneath the tropical forest floor, some of which rival the size of Cambodia’s capital, Phnom Penh.
Another talk for readers in Bangkok – this one by Damian Evans on LiDAR in Angkor.
Using Airborne Laser Scanning to Uncover, Map and Analyse Ancient Landscapes in Cambodia & Beyond
A Talk by Dr. Damian Evans
Date: Thursday, 4 February 2016
Time: 7:30 p.m.
Venue: The Siam Society
Traditionally, scholarship on the Angkor period has focussed on three main areas: architecture, inscriptions and art history. In recent years however there has been increasing interest in the human and environmental context of the temples, and archaeologists are beginning to understand much more about the urban and
agricultural networks that stretched between and also far beyond the well-known monuments of places like Angkor. Even though the cities that surrounded the temples were made of wood, and the water management systems were mostly made of earth, we can still very clearly see and map the traces that remain on the surface of the landscape using remote sensing techniques such as aerial photos and satellite imagery. Until recently, however, archaeologists who focussed on the mapping methods faced one very serious limitation: the fact that vegetation covers much of the areas of interest, and limits our ability to see and map these ancient features. Since 2012 however archaeologists in Cambodia have been using the technique of airborne laser scanning or “lidar”, which has the unique ability to “see through” vegetation and map archaeological remains, even underneath thick forest or jungle. This presentation will outline past, present and future projects involving lidar, including presenting some preliminary results from the latest lidar campaign in 2015, which increased coverage from Angkor to include a wide array of sites across Cambodia, and discuss potential applications in other countries in Southeast Asia including Thailand.
A recent paper by Kasper Hanus and Damien Evans is featured by the Khmer Times – a discussion about population estimates of Angkor through measurements of the ponds in Angkor, a metric made easier to count due to their detection by LiDAR.
The secret to the number of people who actually lived in the city center of Angkor Thom may lie not in the number of buildings but in the number and size of its ponds, according to a new archaeological study released last week. Until now, most research about the Angkor city center has focused on the grand temples, while the mundane details of everyday life – such as where the city’s residents got their water – have been ignored. This new study, published last week in Archaeological Prospection, finds secrets in these mundane details.
Since ponds were used as the water supply by the city’s residents, the team of researchers – led by Kasper Hanus of Adam Mickiewicz University in Poland and Damian Evans of the University of Sydney – hypothesized that the number of ponds could provide a clue to the number of residents. “Small-scale ponds were a vital part of the water management system of Angkor,” the study said.
Counting the number of ponds that existed in the 14th century can be a difficult task, but using detailed maps created with airborne laser scanning, and making clever use of a depth mapping algorithm, the archaeological team was able to estimate the number of ponds in the area.
The latest issue of Antiquity has a special section featuring the latest research on Angkor Wat, which is written by a number of my colleagues and friends. Among the papers discussed are the discovery of towers and previously unknown features within Angkor Wat, the results of the lidar scan in the greater Angkor region, and the fortification walls of Angkor Wat. Here are the links to the journal articles – the first paper is open access, but the rest unfortunately aren’t.
We’ve seen quite a few stories about the LIDAR imaging of Angkor that has revealed a host of new data about the urban sprawl of Angkor, and now the project is on to its second phase. You can read more about their effort on the website, the Cambodian Archaeological LIDAR Initiative.
A new LiDAR survey of Angkor will start this year, which will cover more regions such as the rest of Phnom Kulen, Banteay Chhmar and Sambor Prei Kuk. It will be the largest aerial archaeological survey every undertaken with LiDAR, and we look to more exciting discoveries to come!
Following the incredible discoveries of the first ‘lidar’ project around Angkor Wat, archaeologists have big hopes for a second, much-larger survey
In 2013, Cambodia made world headlines when an expansive survey using airborne laser technology revealed not only that the city of Angkor was even more monumental than previously thought, but that another enormous ancient city, Mahendravarpata, lay beneath the jungle-covered plateau of Phnom Kulen, northeast of Siem Reap.
Now a second, even more expansive survey is about to take place using the same laser imaging detection and ranging technology, known as ‘lidar’.
Aerial lidar surveys involve firing millions of laser beams at the ground and measuring the time they take to bounce back, using tiny differences in time to calculate elevation variations.