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| Drone derived slope model of portion of Zuleta. |
The Pyramids of Zuleta are one of the hidden treasures of the Andes. Built around 1,000
years ago, by the native Caranqui people, these earthen mounds and platform
pyramids dominate the landscape near Hacienda Zuleta. Unlike much of our planet, high resolution
aerial imagery and digital elevation models are unavailable for this part of
the world. This is due to the fog that
often blankets the area and the agrarian nature of the region. As a part of a team of archaeologists who visited the site in the August 2013, we aimed
to change that.
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| Comparison of Landsat Imagery (best public data available) vs. UAV |
Using a small, hand-launched, Unmanned Aerial Vehicle (UAV aka drone)
equipped with a downward facing camera and a sophisticated autopilot system, we
documented the site as it has never been seen—from extremely
low altitude and at high resolution.
This was a challenging task as most of the pyramids are located in the
bottom of steep constricted canyon inhabited by Andean Condors. To make things more challenging there were
high winds, clouds, and quirks of the micro-climates within the canyon to
contend with. In spite of that, we were able to fly nine missions and collect
hundreds of photographs in just a couple of days.
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| Programming the UAV while in flight. |
The UAV flies in a defined pattern and as it collects
photographs. The onboard autopilot insures that each image has 60% or more
overlap with adjacent images.
These
overlapping images allow for the data to processed into 3D and digital terrain
models (DTMs) using photogrammetric and cutting edge Structure from Motion
technologies.
All of the data are GIS ready. While basic processing
allowed us to see the mapped data in the field, it was necessary to
further develop it using a high-end processing farm in Maryland, once we were back in
the States.
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| Radiance scaled enhancement of UAV data. |
This approach has already led to the discovery of many more
mounds that are not obvious to the naked eye but stand out in the data.
Furthermore, it is the first time the
detailed spatial relationship between each of the earthen structures can be
explored with precision.
This data will be
used to track the condition of the mounds over time and has created a digital
snapshot of their current state for future generations to ponder. This was
accomplished with only a few days of fieldwork and under harsh conditions.
To create a map of similar accuracy using
traditional survey approaches would have taken weeks and lacked the aerial
imagery this approach provides.
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| Pyramids deep within the canyon. |
Our team has conducted similar mapping missions in
Australia, Belize, Belgium, Fiji, France, Germany, The Republic of Kiribati,
Peru, and South Africa. We look forward to continuing these sorts of projects
elsewhere and helping to preserve and understand our past.
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| Hand launching the drone. |
The archaeological mapping and processing team included
Chet Walker and
Mark Willis.
The rest of the
archaeological team was made up of Steve Athens and David O. Brown. Athens and Brown are
experts on the archaeology of the Andes and have worked for decades in the
region.
We would like to thank Fernando Polanco Plaza, the general manager of
Hacienda Zuelta,
for his hospitality and
dedication to preserving the rich heritage of Ecuador.
