Observing Western Sinai from Space

Investigator:

Sarah Parcak
Near Eastern Languages and Civilizations/Archaeological Studies, Yale University and
Department of Archaeology, Cambridge University

Advisors:

DUS, NELC: John Darnell
DUS, Arch. Studies: Gail Hoffman

Description:

This project was commenced with the idea of applying various remote sensing techniques in the identification of new sites in the El-Markha Plain area for the South Sinai Survey and Excavation Project, a long term project in Egypt that was commenced in summer 2000. A portion of an image taken August 21, 1991 was analyzed, and a variety of remote sensing techniques were applied. The implementation of these various techniques in the identification of the new sites shall be discussed along with the future goals of the project.

There are a number of methods for identifying archaeological sites from space. Tells can be quite large (some up to a kilometer or more in size), and thus would be relatively easy to view on an image with a 30m x 30m pixel resolution. Other sites can be much smaller, but often display architectural features that would also be clear from space. The El-Markha region presented a unique set of problems for carrying out archaeological reconnaissance. It is a sandy region, and has slight mounds, which, based upon former ground-truthing work are only between 1 and 2 meters tall. These would be quite difficult to discern from the surrounding landscape in any satellite image. Also, the ancient Sinai tells are composed primarily of sand, just like the rest of the El-Markha plain. How, then, can archaeological sites be found in coastal sandy regions?

Many coastal archaeological sites, (the coastline of Israel is a good example), have a high concentration of vegetation growing on and around them in comparison to the rest of the coastline. Archaeological sites usually contain decomposing bone and related material culture, as well as (in many cases) architectural remains. These provide 1) a nutrient rich soil on which the plants can grow and 2) in-situ remains around which the plants can safely grow their roots. Without the nutrients provided by the remains, the plants would not be able to grow in such abundance, and without architectural remains, the plants would be blown away due to wind and coastal storms. Thus, applying NDVI (Normalized Difference Vegitation Index) to the discovery of new sites in the El-Markha Plain seems pertinent.

Though there is not a great deal of vegetation growing along the El-Markha Plain, areas that have a positive NDVI should have a much greater chance of being an archaeological site than those areas that do not. This hypothesis was tested on a known site rediscovered last summer, Abu Zeynima. For the site, the NDVI was found to be positive. Based upon this test case, it was decided that NDVI would be used as one method for identifying new sites. In the El-Markha plain, the majority of the area has a negative NDVI value because the sandy region, the water and the wadi areas reflect more strongly in the visible than in the near infrared wavelengths. Even though the region is mostly sand, ground-truthing trips to the area in Summer 2000 showed that during the driest season of the year there was still vegetation covering a number of small hills.


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5 June 2001