Changes in how archaeologists study the past are being brought about by advances in LiDAR technology. LiDAR, which stands for Light Detection and Ranging, is a method of remote sensing that uses light to measure varying distances to the Earth. This light is in the form of a pulsated laser, and these pulses can be used to produce exact data about the characteristics of Earth’s surface. LiDAR instruments are made up mainly of a laser, a special GPS receiver, and a scanner typically attached to an airplane or helicopter for use over a wide area.
One of the places that LiDAR is having a significant impact in is the archaeological study of New England. Today, New England is heavily forested, which makes it extremely difficult for archaeologists to get a better understanding of how the region looked in colonial times. During the 1700s, New England was covered with roads, farm walls, and homesteads, but after they were largely abandoned in the 1950s, the forests grew back. Through the use of LiDAR, however, archaeologists are now able to uncover more of this ‘lost’ New England of subsistence farming, something many people have no idea existed.
Uncovering the past: GIS analysis of archaeological features under New England forests using high resolution topographic data (LiDAR) | Katharine Johnson - Academia.edu
Archaeology Applications
Lidar has many applications in the field of archaeology including aiding in the planning of field campaigns, mapping features beneath forest canopy, and providing an overview of broad, continuous features that may be indistinguishable on the ground.[20] Lidar can also provide archaeologists with the ability to create high-resolution digital elevation models (DEMs) of archaeological sites that can reveal micro-topography that are otherwise hidden by vegetation.LiDAR-derived products can be easily integrated into a Geographic Information System (GIS) for analysis and interpretation. For example at Fort Beauséjour - Fort Cumberland National Historic Site, Canada, previously undiscovered archaeological features below forest canopy have been mapped that are related to the siege of the Fort in 1755. Features that could not be distinguished on the ground or through aerial photography were identified by overlaying hillshades of the DEM created with artificial illumination from various angles.
With lidar the ability to produce high-resolution datasets quickly and relatively cheaply can be an advantage. Beyond efficiency, its ability to penetrate forest canopy has led to the discovery of features that were not distinguishable through traditional geo-spatial methods and are difficult to reach through field surveys, as in work at Caracol by Arlen Chase and his wife Diane Zaino Chase.[21]
The intensity of the returned signal can be used to detect features buried under flat vegetated surfaces such as fields, especially when mapping using the infrared spectrum. The presence of these features affects plant growth and thus the amount of infrared light reflected back.[22] In 2012, Lidar was used by a team attempting to find the legendary city of La Ciudad Blanca in the Honduran jungle. During a seven−day mapping period, they found evidence of extensive man-made structures that had eluded ground searches for hundreds of years.[23] In June 2013 the rediscovery of the city of Mahendraparvata was announced.[24]
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