The Nuts and Bolts of Aerial Archaeology

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On this page we will discuss the equipment and techniques used to gather archaeological data through "remote sensing."

Archaeological information can be recorded by something as complex as an airborne thermal scanner or as simple as an observer with a notebook looking at a shadow. Sometimes the simplest and least expensive methods are the most effective. Some of the best aerial archaeology worldwide has been accomplished by nothing more exotic than experienced observers flying around in airplanes examining the landscape for signs of ancient activity. Before aircraft were invented such scanning was even done from hilltops.

Practically any human activity that modifies the ground will leave marks that endure for centuries, and can best be seen from the air (or only from the air). Three primary visual indicators of an archaeological site are:

1. shadows
2. vegetation patterns
3. ground colors and textures

As you might expect, all three of these indicators can change daily, and seasonally. Even some ground colors and soil stains are due to the amount of dampness in the topsoil, which also changes constantly. That is why an archaeological site that stands out strikingly at a certain time of day, or season of the year, or in certain kinds of weather (wet or dry), might disappear entirely at other times.

An aerial observer might see an archaeological site one day only to find it gone the next, or see it at dawn but not at noon.

If "a picture is worth a thousand words," then to economize on words we will let aerial photographs illustrate how the three above factors: shadows, vegetation patterns, and ground color or texture can create the contrast necessary to reveal an archaeological site to the aerial observer. These three elements can work in combination as well as singly, of course, and the aerial archaeologist always hopes for such situations, but I will use photos from our Southwest U.S. files here that show each as a largely isolated phenomenon.

1. Shadow sites: aerial photo (37K) Pueblo She'

2. Vegetation patterns: aerial photo (43K) Sapawe Pueblo

3. Ground colors and textures: aerial photo (40K) Mystery stone designs

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