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occupation of around 1300AD and an abandonment 300 years
later. Shortly after that, people returned to this area, and under
the hand of Spanish religious leaders, the native peoples built
the mission church, Za Purísima Concepción. The church was
erected in the early 1630's and in use for approximately 40
years (Wilson, 1993; Gifford, 1988). The ruins include nearly
complete walls, up to 12 meters in height that still show the roof
beam support holes. The church was built so as to be attached
to the existing pueblo (Figure | and 2). Although the entire site
will need to be documented, this experiment focused on the
church itself because of it’s size and current state of
preservation.
Figure 1. Mission church, La Purisima Concepciôn, associated
with the Quarai pueblo ruins of Salinas National Monument.
Quarai pueblo ruins group and the associated mission church, La Purisima Concepción (highlighted),
in the Salinas Pueblo Missions National Monument
0 5 10 15 20 25 meters
Figure 2. Map of the Quarai pueblo ruins'of Salinas National
Monument.
2. TOOLS AND METHODS
The methods employed for this process are unique to the
photographic equipment that was employed. Technological
advances are making digital photography a viable alternative
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part BS. Istanbul 2004
for documentation. Digital photogrammetry is more accessible
due to advancements in and availability of the software. This
section will discuss the tools used for this documentation
experiment and the methods developed to utilize these tools.
2.1 Tools
Two cameras were used in this project, one in each application.
The camera used for the first experiment was a Nikon 990 with
an FC-ES8 fish-eye lens. The Nikon 990 is capable of capturing
images at a maximum resolution of 2048 x 1336, or 3.2
effective megapixels. The FC-E8 lens has a viewing angle of
183 degrees, magnification of 0.209x and an 8mm focal length.
This provided the ability to capture a larger area without having
to take multiple pictures, allowing the reduction of person-
hours in recording and processing images. The second
experiment utilized a slightly newer model of camera and lens,
the Nikon Coolpix 5700 and the Nikon Fish-eye lens FC-E9.
The Nikon 5700 has a resolution of 2560 x 1920 pixels, or 5
megapixels, and the FC-E9 features approximately 183-degree
coverage with a focal length of 7mm and magnification of 0.2x.
These cameras were chosen for the high-resolution capability
necessary for detail in documentation.
The photogrammetric software used in the project was
PhotoModeler Pro 4.0 by EOS Systems, Inc. This was used to
perform the camera calibrations and to conduct the digital
photogrammetric processing. It is an affordable, readily
available off-the-shelf software package.
2.2 Methods
The process of the digital photo documentation involved three
stages. The first involved calibrating the camera and lens to the
digital photogrammetric software that was to be employed. The
second stage was to acquire the images, and the third was to
digitally process them in the photogrammetric software
computer program.
2.2.1 Camera Calibration: The calibration of the camera to
the PhotoModeler software was necessary to remove the
distortions that are inherent in the lens. This process was
particularly important for this experiment, as it was necessary to
also remove the extreme distortion caused by the fish-eye lens.
This particular type of lens had never been utilized with this
software before, and therefore a full calibration had to be made.
which involved some intervention on the user’s part to
manipulate the calibration software to see what it was unable to
register. This process had to be performed twice, as two
different sets of cameras and lenses were used in the project.
2.2.2 Image Acquisition: The digital photographs were
acquired by mounting the camera on a tripod at a height of
approximately four feet. Because the fish-eye lens captures
large areas horizontally and vertically, the photographer can
capture whole walls from a near-ground level, making elevation
of the camera and operator unnecessary. The photos had to be
taken sequentially along a wall if the structure was too long to
fit into a single image. The images also had to be overlapping
by approximately 60% to allow photogrammetric processing.