January 13, 2004
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D. M. Fitzgerald, G. A. Zarillo & S. Johnston
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shoal volumes, measuring coastal change using data derived from aerial photogra-
phy can be found in widely available coastal engineering publications (Rosati and
Kraus, 1999). However, despite the widespread use of aerial photography and as-
sociated photogrammetric methods in coastal studies, image analysis methods to
more efficiently and automatically extract data from digital imagery have not been
in widespread use by the coastal engineering community. Image analysis methods
commonly applied for land use studies, oceanographic data collection and meteoro-
logical monitoring can be adapted to improve data collection and analysis for coastal
engineering.
Traditional remote sensing methods involve examination of the spectral signa-
ture of remote sensing data using image analysis techniques. The principles of re-
mote sensing and image analysis can be found in textbooks such as the Manual
of Remote Sensing (American Society of Photogrammetry, 1983), Remote Sensing
and Image Interpretation (Lillesand and Kiefer, 1994), Introductory Digital Image
Processing (Jensen, 1996), and many others. The major categories of image analysis
include digital filtering, image registration, image enhancement, and image classi-
fication. To date image registration has been the most frequently used image pro-
cessing methods in general use for coastal engineering studies. An example is the
digital orthographic quarter quadrangle (DOQQ) aerial imagery that has been freely
distributed by the US Geological Survey (USGS). These digital images have been
widely applied by coastal zone managers to provide base maps for developing land
use themes in GIS format. Digital handling of the image raster data using data deci-
mation schemes allows desktop viewing and manipulation of large image files having
a spatial resolution as fine as 1 m without compromising computational effort.
GIS technology was developed as an extension to traditional mapping methods
once computing technology advanced to a point of rapid calculations. Similar to
remote sensing technology, GIS methods have only been slowly adopted as a tool in
coastal engineering. Recent improvements in computer software and hardware have
allowed both remote sensing and GIS to assume a major role in the managements of
coastal resources. State and Federal agencies in the United States use GIS technology
to archive and disseminate data critical for coastal zone management. As an example,
the NOAA Coastal Services Center in Charleston, SC is a clearinghouse for spatial
data relating to the management of coastal environments. Among the data sets that
are available in GIS are vectorized shoreline data, land use themes for United States
coastal regions, benthos habitat data, and coastal change data. Many of these data
sets combine remote sensing data and GIS methods for convenient display.
The essentials of GIS methods can be found in textbooks such as Fundamen-
tals of Geographic Information Systems (Demers, 1996). The improving speed and
mass storage of desktop computing during the 1990s provided an opportunity to
combine remote sensing and GIS methods into a single desktop platform. An exam-
ple is the adaptation of the USACE SBAS software to the ArcViewTM GIS platform
(Rosati and Krau, 1999). This software package combines aspects of remote sensing
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