TM 5-852-2/AFR 88-19, Vol. 2
listing of available images will be sent along with an
features that are normally unsuitable for building
order form and a key to explain the information in
sites, such as areas of high elevations (mountainous
the listing. The computer listing will identify all
terrain), or thermally unstable and sensitive areas
images and photographs available over op close to
(thaw lakes and permafrost zones). By considering
an area of interest. Each image or photograph will
the large river that traverses the scene as a possible
be described in two printed lines on the computer
way to get into the area, an area of interest to be
listing. A number of entries may be listed, depending
studied in greater detail was selected. This area is
on the size of the area selected and the restrictions
enclosed in the rectangle on the overlay. Of
of the supplemental data. Imagery or photography
particular interest was the river, its broad floodplain,
may be available from more than one source (e.g.,
and the dissected terrace area, which might be
from Landsat, Skylab, NASA aircraft, or aircraft of
suitable for a construction site. Therefore, based on
the U.S. Geological Survey or other agencies) all of
a monoscopic pattern analysis of a large area
which differ significantly in sensor or camera
(approximately 13,225 square miles), involving the
characteristics. Thus, each entry on the computer
delineation of photo patterns associated with
listing should be carefully studied to determine the
topography, drainage and permafrost conditions, an
best selection for the purposes under consideration.
area was selected for further, more detailed study
The first line of each entry on the computer listing
(with aerial photography). The selection should be
gives data characteristics, along with information
based on the scale and scope of the project.
required for subsequent ordering. The second line of
3-3. Localized area analysis procedures.
information denotes the geographic coordinates (by
latitude and longitude) of each individual image.
a. Obtaining existing stereoscopic aerial photo-
c. Method of using Landsat images. Landsat
graphy. While there still are areas in the earth's
images provide an ideal basis for conducting a
arctic and subarctic regions where no aerial pho-
regional terrain analysis of an area of interest. To
tography has ever been acquired, it is more usual to
demonstrate the use of these products, a hypothet-
find that there is adequate airphoto coverage of
ical terrain analysis for site selection has been
these regions. The primary reason for photograph-
conducted and is portrayed in the series of illustra-
ing these remote areas in the first place was to
tions that follow. Based on the computer search for
produce maps. More recently, the exploration for
a suitable Landsat image, the four bands of imagery
natural resources in arctic and subarctic areas has
of an area of Alaskan terrain were ordered and
led to even more aerial photography coverage.
appear as figure 3-1. The false color composite
Aerial photography aimed at mineral and other
(shown in black and white in fig. 3-2) was formed
natural resource explorations has been, and is being,
by the superpositioning of bands 4, 5 and 7 through
done by both governmental and private
corresponding filtration. When available, the false
organizations for many of the countries bordering
color composite should be ordered for site selection;
the Arctic. In the United States, for example, the
otherwise, either bands 5 or 7 would be usable.
U.S. Geological Survey, Bureau of Land Manage-
(1) The Landsat series of images do not produce
ment, National Park Service, State of Alaska, and
stereoscopic images. There is only about 10%
the Department of Transportation have flown aerial
endlap between frames. At high latitudes where
photography missions in Alaska, so have many
orbital paths converge at the pole, sidelap stereo can
major U.S. oil companies and the Alaska Pipeline
be observed between images of adjacent orbits.
Service Company (Alyeska). An increasing amount
However, because of the high altitude at which
of aerial photography is being acquired for
these images have been obtained, only large,
environmental research projects being done in arctic
mountainous features tend to express much sense of
regions.
topographic relief. The primary use of these Landsat
(1) In addition to these sources, the Defense
images for analyzing terrain is to conduct a
Mapping Agency, the Defense Intelligence Agency,
monoscopic (not stereoscopic) pattern analysis.
the U.S. Air Force and U.S. Navy periodically
(2) The overlay presented as figure 3-3 is a
acquire aerial photography of arctic areas. Unfor-
result of a monoscopic pattern analysis of the false
tunately, there is no one organization that keeps up
color composite Landsat image (fig. 3-2). The
to date on all the aerial photography produced in
legend briefly describes the categories of terrain
these regions. As far as the United States is
information derived by analyzing patterns on the
concerned, the EROS Data Center of the USGS at
Landsat scene. Much of the area consists of terrain
3-2
Previous Page
