Page 22 - ImmenseJourney

21st-Century Technology Meets the 13th Century

During the summer of 2009, 21st-century tech- intensely from the moist, organic-rich soil within the Taking a GIS a step farther, archaeologists used the
nology encountered the 13th century in western house depressions. As a result the depressions appear layers of information about site locations such as
Iowa, and the results are outstanding. Airborne Light darker than the surrounding surface. proximity to streams, slope, and soil type, to model
Detection and Ranging (LiDAR) is a remote sensing the environmental preferences Glenwood people
technology used to gather elevation data over a large Using a geographic information system (GIS), maps may have had in selecting areas for habitation. The
area. Iowa is one of the first states to have LiDAR, of soils, topography, and archaeological sites were goals of the study were to explore on what kind of
and the Loess Hills study represents the first use of layered atop one another and linked to a computer land lodges are usually found, and what kind of land
LiDAR to detect late prehistoric lodge sites. database of information about each of these features. Glenwood people preferred when deciding where to
LiDAR images, manipulated by a GIS, enhanced the build. A GIS allowed the study to compare and cal-
Picture an aircraft mounted with a device that scans view of features not obvious from ground level. These culate the values to study the relationship between
the ground images revealed: lodges and the landscape.
surface with an
invisible laser. • 129 lodge depressions at 73 sites (previously !(
Like sunlight, the only 86 lodges were recorded at these sites), (!
laser light can
filter between • 66 potential new lodge depressions, !((!!((!
tree branches • 8 lodge sites never precisely located, and
and sometimes • 20 lodge sites previously identified only as !(
through leafed-
out tree canopy. artifact scatters. !(!( !(
The elevation of
an object or the The efficacy of LiDAR in locating sites not only sur- (!
surface is determined by the time it takes the laser passed expectations but provided new insights into
pulse to reflect back to a sensor on the plane. The el- the arrangement of Glenwood earth lodges. In the !(!( !( !( !(
evation data includes tops of buildings, tree branch- course of the study, a dozen suspected lodges were (!
es, cars, and, in this instance, the subtle depressions found to be paired depressions similar to the twin !(
created by well preserved earth lodges in Mills and lodges at site 13ML102.
Pottawattamie counties! (! (!
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Some of the southwest Iowa sites had escaped the !( !( (!
attention of collectors and archaeologists for over
100 years. LiDAR was able to detect lodges due to (!(! (!
the slight elevation differences created by the house
depressions and because laser light is reflected less !( (! !(
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Archaeological preserve !( !(

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by LiDAR in Mills County
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0 1 2 Miles

20 University of Iowa Office of the State Archaeologist