Archive

Posts Tagged ‘lidar ranging’

New discoveries in Cambodia

June 20th, 2013 No comments

New discoveries in Cambodia by an Australian team from the University of Sydney are another confirmation that lidar will be a game changer for the discipline, just as radio carbon dating was in the 1950s.

Long term readers of this blog will know of my continuing interest in lidar (light detection and ranging) in archaeology (see past post).

The ability to fly over dense forest and build up a 3D picture of what may have once lain beneath is quite phenomenal.  Unfortunately it´s also expensive, as the going international rate for a helicopter is around $1000 an hour – rather more than it costs for a few volunteers to scrape away at the dirt on a traditional dig. The Australian team covered some 370 sq kms in Cambodia so the bill must have been eye-watering – but worthwhile.

.

They uncovered ´the ruins of five other previously unrecorded temples and evidence of ancient canals, dykes and roads´, which they confirmed on the ground after lidar had indicated their presence;  all this was in the area of Phnom Kulen, an antecedent of the neighbouring Angkor Wat temple complex in north-western Cambodia. A collateral benefit is that it will provide conservation and tourism work for the dirt-poor locals who were unaware of the temple complexes nearby.

One important point is that while lidar may make completely fresh discoveries, it can also help shade in existing ones – that while, say, all the churches of a medieval town might have survived, now we can trace in all the other buildings and roads to give a more complete picture of the settlement.

Watch this space for more, as they say….

More detail – and a video – on the discoveries in Cambodia

Lidar ranging

May 12th, 2010 No comments

There’s nothing as seductive as new technology, particularly in the world of archaeology.   Some years ago I co-led an expedition that expended an inordinate amount of energy using a thermal imaging camera.  We flew over the cloud forest near Machu Picchu to determine the full extent of the nearby site of Llactapata, at a cost of $1000 per hour for the plane, let alone for the camera.  Its infra-red vision was supposed to be able to detect the difference in temperature between stone buildings which retain heat, and vegetation which does not.  By using it, we hoped to  be able to see through the cloud-forest to any ruins below the canopy  – the archaeological equivalent of those X-Ray specs sold in schoolboys’ comics to look through women’s skirts, and in the event about as successful.

We ended up going into the forest on foot and looking in the more traditional manner, with machetes, frustration and a great deal of sweat.  (The full story is told in Cochineal Red for those interested.)

But an even newer technology has come along that sounds rather more effective:  lidar (‘light detection and ranging’).  Gamers have used it to create virtual reality sites for some time.   Now the husband-and-wife team of Arlen and Diane Chase have adapted  it at Caracol in Belize to penetrate the jungle cover and create 3-D images of one of the great cities of the Maya lowlands.

In the process they’ve established that the site was far more extensive than had ever been expected:  the city sprawled over some 70 square miles.

Diane Chase was quoted as being  ‘blown away’ by the new technology:   ‘We believe that lidar will help transform Maya archaeology much in the same way that radiocarbon dating did in the 1950s and interpretations of Maya hieroglyphs did in the 1980s and ’90s.’

Apparently, however,  they also emphasized that ‘it would not obviate the need to follow up with traditional mapping to establish “ground truth.” ’  What a terrific phrase – ‘ground truth’.  Now that’s something I’ve been searching for my whole life…..