Scanning an empty field that once housed a Shaker village in New Hampshire, Jesse Casana had come in search of the foundations of stone buildings, long-forgotten roadways and other remnants of this community dating to the 1790s.
But instead of a trowel and shovel, Casana and his Dartmouth College colleague Chad Hill are using a drone equipped with a thermal imaging camera and mapping instruments.
The camera can identify remnants of buildings and other structures up to several feet below the surface, since the temperatures of that brick or stone material is often warmer than the soil around it.
Dartmouth's Chad Hill readies a drone to be flown over a site of a Shaker Village in Enfield, NH. The cameras use heat differences between stone and the soil surrounding it to identify structures below the surface like foundations of buildings, which then can be further explored
The team was able to recognize traces of long-removed historic buildings and pathways at the Shaker Village in Enfield, N.H.
The community once housed nearly 100 buildings but was sold in the 1920s and is now an outdoor history museum.
It is dedicated to preserving and sharing the history of the Shakers, a Protestant religious denomination, who lived on the site from 1793 to 1923
The drone found stone walls, cellars and even a well.
And by using the drone, the researchers can survey an area in minutes that might take months with traditional methods.
'If you look, you see a flat field but below it there are big stone walls.
'There are cellars.
'There is a big old well, all kinds of stuff you can't see on the ground,' Casana said of a community that once housed nearly 100 buildings but was sold in the 1920s and is now an outdoor history museum.
'Those things have different thermal properties.
'If you capture an image at the right moment, you can see it — which is amazing.'
Archaeologists have for decades have used aerial photography and more recently satellite imagery and data from laser sensors known as Lidar to map and discover new sites.
What the drone saw: (a) Color orthoimage of a survey area at the Enfield Shaker Village, New Hampshire, showing location of historic buildings indicated on a 1917 map; (b) magnetic gradiometry survey data; (c) raw thermal imagery collected with a radiometric thermal camera; and (d) thermal imagery processed to show only values present in the lawn.
The field is further transforming with the emergence of cheap drones, resulting in several significant discoveries in Asia, South America and the Middle East, including a massive manmade stone platform spotted last year hidden under sand in the ancient city of Petra in Jordan.
Casana and Hill have taken the process a step further by adding a thermal imaging camera.
So far, Casana said, the camera technology has proved a success at arid locations without a lot of vegetation and where the structures are near the surface.
In this Nov. 14, 2017 photo, Dartmouth's Chad Hill studies a screen showing data collected by a drone at a the site of a Shaker Village in Enfield, N.H. Hill and Jesse Casana are using drones equipped with thermal imaging cameras to study a half-dozen archaeological sites around the world. The cameras use the heat differences between stone and the soil surrounding it to identify structures below the surface, which then can be further explored. (AP Photo/Michael Casey)
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