THE TECHNICAL PAGE
The Nuts and Bolts of Aerial Archaeology
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