Remote sensing (archaeology)

Remote sensing techniques in archaeology are an increasingly important component of the technical and methodological tool set available in archaeological research. Rindfuss,Ronald R and Stern, Paul C. Linking Remote Sensing and Social Science: The Need and the New Challanges."People and Pixels: Linking Remote Sensing and Social Science."National Academy Press. Washington D.C.1998. ,] . The use of remote sensing techniques allows archaeologists to uncover unique data that is unobtainable using traditional archaeological excavation techniques.

General techniques

Remote Sensing methods employed in the service of archaeological investigations include:
*Subsurface Geophysics
**Metal detecting
**Electrical Resistivity
**Ground Penetrating Radar
**Magnetometry
*Aerial and Satellite Imaging
**Aerial photography
***Multispectral and Hyperspectral Sensors
***Thermal Infrared Multispectral Scanner (TIMS)
***Color Infrared Film (CIR)
***Microwave Radar
**Satellite Imaging
***Laser altimeters or light detection and ranging (LIDAR)
***Synthetic Aperture Radar (SAR)
***INSAR - Interferometric SAR

Examples of regional applications

Maya research

Some of the most prominent remote sensing research has been done in regard to Maya studies in Mesoamerica. The Petén region of northern Guatemala is of particular focus because remote sensing technology is of very definite use there. The Petén is a densely forested region and it lacks modern settlements and infrastructure. As a result, it is extremely difficult to survey, and because of this remote sensing offers a solution to this research problem. The use of remote sensing techniques in this region is a great example of the applications these methods have for archaeologists. The Petén is a hilly, karstic, thickly forested landscape which offers an incredible barrier for field archaeologists to penetrate. With the advent of remote sensing techniques, a plethora of information has been uncovered about the region and about the people that inhabited it.

The Petén is arguably one of the most difficult of the Maya landscapes in which to subsist. It is questions regarding subsistence patterns and related problems that have driven remote sensing methodology in the hopes of understanding the complex adaptations that the Maya developed [http://www.pbs.org/wgbh/nova/sciencenow/3401/03-ask.html NOVA Science interview] ,] . Remote sensing methods have also proven invaluable when working to discover features, cisterns, and temples. Archaeologists have identified vegetative differentiation associated with such features. With the advent of remote sensing, archaeologists are able to pinpoint and study the features hidden beneath this canopy without ever visiting the jungle.

A pioneer in the use of remote sensing in Maya research is NASA archaeologist Tom Sever, who has applied remote sensing to research in Maya site discovery as well as mapping causeways ("sacbeob") and roads. Sever has stressed the enormous use of remote sensing in uncovering settlement patterns, population densities, societal structure, communication, and transportation [http://wwwghcc.msfc.nasa.gov/archeology/peten.html NASA archaeology website] ,] . Sever has done much of his research in the the Petén region of northern Guatemala, where he and his research team have used satellite imagery and GIS to map undiscovered roads and causeways the ancient Maya built to connect cities and settlements. These landscape artifacts represent the advantage of using remote sensing as these causeways are not visible from the ground. By mapping these forms, Sever is able to locate new sites and further uncover ancient Maya methods of communicated and transportation. Sever and his team also use remote sensing methods to gather data on deforestation. The rain forests of the Petén are undergoing massive deforestation, and Sever's remote sensing offers another window into this understanding and halting this problem. Monitoring the rate of deforestation not only has important ecological value, but the use of remote sensing can detect landscape change. By measuring the magnitude of landscape change in terms of vegetative cover and [soil geography] , as well as shifting land use patterns and the associated cultural diversity, archaeologists are given a window into depletion rates and trends in anthropogenic landscape alteration.Sever, Thomas L.Validating Prehistoric and Current Social Phenomena upon the Landscape of the Peten, Guatemala."People and Pixels: Linking Remote Sensing and Social Science."National Academy Press. Washington D.C.1998.,]

Much attention has been devoted to the mapping of canals and irrigation systems Pope, Kevin O. and Dahlin, Bruce H.Ancient Maya wetland agriculture: new insights from ecological and remote sensing research."Journal of field archaeology".Vol. 16 p. 87-106. 1989] . Synthetic Aperture Radar (SAR) has proved particularly useful in this research. SAR is a type of radar that is sensitive to linear and geometric features on the ground [http://wwwghcc.msfc.nasa.gov/archeology/peten.html NASA archaeology website] ,] . It is also important include a method called ground truthing, or the process of physically visiting (on foot) the localities surveyed to verify the data and help inform the interpretation. GPS is often used to aid in this process.

Geophysical methods have also been employed in Maya research. Ground Penetrating Radar (GPR) has been performed on a number of sites, including Chichen Itza. The GPR research has detected buried causeways and structures that might have otherwise gone unnoticed Desmond, Lawrence G. and William A. Sauck.Entering the Maya Underworld: A ground penetrating radar Survey at Chichen Itza, Yucatan, Mexico. Innovation et Technologie au Service de Patrimoine de l'Humanite, Actes du colloque organise par Admitech en collaboration avec l'Unesco, Paris, 24 June 1996, pp. 23-30.] .

Maya "collapse"

One of Sever's research goals is understanding the comparatively sudden decline of many Maya centers in the central Lowlands region by the end of the 1st millennium CE, a happenstance often referred to as the "{Classic) Maya collapse". Sever's research on communication and transportation systems points to an extensive societal infrastructure capable of supporting the building and maintenance of the causeways and roadways. Using satellite imagery, researchers have been able to map canals and reservoirs. These offer a glimpse into Maya cultural adaptations during the period of their highest population density. At the height of the classic period, the population in the Maya lowlands was 500 - 1300 people per square mile in rural areas, and even more in urban regions. This far outweighs the carrying capacity for this region, but this follows centuries of successful adaptation. Other data shows that by the end of the classic period, the Maya had already depleted much of the rain forest. Understanding how the ancient Maya adapted to this karst topography could shed light on solutions to modern ecological problems that modern peoples in the Petén currently face, which is much the same, except there are fewer people who are causing even more damage to the biodiversity and cultural diversity Sever, Thomas and L and Irwin, Daniel E.LANDSCAPE ARCHAEOLOGY: Remote-sensing investigation of the ancient Maya in the Peten rainforest of northern Guatemala. Ancient Mesoamerica. Issue 1, vol.14. January 2003] . Sever believes that the Maya collapse was a primarily ecological disaster. By detecting deforestation rates and trends can help us to understand how these same processes affected the Maya.

References