COLLINS, DOERING, AND CARR INTEGRATED SPATIAL TECHNOLOGIES

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Figure 6. Cut hole forming part of the Royal Palm Circle feature with
associated faunal material present.

 

Figure 7. Three dimensional scan data of Miami Circle showing detail of
terrain and intrusive historic elements (i.e., Septic tank, planter footing and
trench cut, thought associated with the former Palm Tree Inn and Brickell
Point Apartments.

of points were mathematically selected in the
scanner software to achieve a workable dataset.
For the Miami Circle HDDS project, a total of
136,766 vertical, horizontal and elevational
points were exported to a text file format for use
in the production of surface maps in a variety of
survey and GIS software platforms (Figure 13).

As a point of technological comparison, the
conventional transit survey collected nearly
4,000 points over a period of 2 weeks in the
field and required 120 work hours (Ryan J.
Wheeler, personal communication, 2003). The
laser scan survey collected in excess of
4,000,000 points in less than 16 work hours. In
addition to the quantitative disparity, each of the
scan data points are accurate to within a milli-
meter, which conventional survey cannot ap-
proximate.

The processed HDDS data also provided
precise and reliable measurements and depic-
tions that were useful in the reformulation and
analysis of the Miami Circle’s layout and di-
mensions. Previous maps of the feature had
been based on an aerial photograph that was
taken from east of the Circle’s center, a position
that caused a parallax distortion of the Circle’s
true shape and size. The error created by this
type of distortion is amplified with distance and
it introduces unanticipated errors into the depic-
tions and, in turn, into the interpretations of the
feature (Figure 14). The scan data were used to
critically address issues of central location,
pattern occurrence, shape, and spatial associa-
tions (Figure 15). When the previously plotted
features were compared against the HDDS data,
the distortion caused by the aforementioned
parallax phenomena became apparent (Figure
16). Because the laser scanner collects spatial
data that are all relative to a single point, distor-
tion does not occur (Alessandri et al. 2005).

A number of other visualizations and dia-
grams were produced through various process-
ing techniques using the Miami Circle HDDS
data. A Triangulated Irregular Network (TIN)
model was generated that proved effective in
the examination of site-specific details such as
slope, aspect, and line of sight, and the model
was used to produce elevation contours across
the feature. Vertical cut marks, similar to those
made by shell tools in replication studies
(Florida Division of Historical Resources
2004a; Wheeler and Carr 2004) were observed
in many of the carved holes and basins. The
shape, morphology, and dimensions of each of
these cavities were able to be carefully exam-
ined in 3D profile (Figure 17). The differences
between the linear historic feature cuts and the

circular features. This procedure does not mean that any of the randomness of the prehistoric basin cuts were clearly
original raw data is discarded, but simply that a lesser number discernable in the new visualizations and demonstrated distinc-