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copters
icopter
volving
logy in
g/posi-
tioning/display software was developed to expedite data
collection and verification. The helicopters are equipped with
GPS receivers that enable the pilots to pre-define their flight
track, conduct real time navigation guided by the GPS unit and
to record the coordinates of landing points or features of
interest. The SPOT mosaic was loaded into a Pentium laptop
computer (100 Mhz) along with the DMS and Field Notes (Pen
Metrics, Inc.) software packages. A Trimble Pathfinder Pro XL
(8- channel) GPS receiver with an external antenna mounted on
the forward hull of the helicopter was then connected to the
serial port of the laptop computer. This set-up enables a person
in the rear seat of the helicopter to hold the computer on his or
her lap, display the satellite image mosaic and track in real time
the flight path of the helicopter. Most importantly, it provides
a means of collecting ground truth information that is linked to
coordinates provided by the GPS receiver. Upon reaching an
area of interest, the helicopter circles at low altitude and/or
lands to allow identification of plants. Species attribute infor-
mation and additional notes pertaining to fire history or exotic
control measures that may have influenced the area are entered
into the computer and linked with the GPS coordinates. This
procedure also can be used with vehicle or foot surveys.
A handheld digital camera, the Kodak Professional DCS 420
(1500 x 1000 pixels) is also being used to capture digital CIR
and true-color images of plant species. Resulting images are
directly accessible by software packages such as the DMS and
Adobe Photoshop for display and enhancement. Positional
information (via a Trimble Ensign GPS unit) and voice an-
notation also can be linked with individual images for location
recovery and the addition of attributes. In South Florida, the
digital camera was used both on the ground and in the
helicopter to document representative plant species and build a
digital photo key corresponding to classes of the Everglades
Vegetation Classification System.
The data gathered during the ground and helicopter surveys are
used to verify vegetation interpretations from the 1994/1995
USGS NAPP air photos. After verification, the digital vegeta-
tion boundary files, along with transportation and hydrographic
data in digital format, are input to the ARC/INFO software
package resident on SUN SPARCstation 10 and IBM RISC
System 6000 workstations, edited, attributed and edge matched
to create the GIS database. Tiles corresponding to the USGS
1:24,000 scale topographic quadrangle series are then plotted
as hardcopy maps.
3. CONCLUSION
Development of a resource database for the national parks and
- preserves of South Florida has demonstrated the advantages of
using GPS, image processing and GIS to facilitate rectification,
analysis and verification of data. For example, GPS derived
control was used to rectify satellite images and to create a
satellite image mosaic that, in turn, served as a source of
ground control for aerial photographs. Once georeferenced to a
standard ground coordinate system within a high degree of
933
positional accuracy, the aerial photographs provide source
information for the derivation/revision of thematic data layers
such as vegetation and land use.
The efficient collection of field data via ground, vehicle and
helicopter surveys for attributing database features and/or
verifying the interpretation of remotely sensed data also is
made possible by GPS. Innovative techniques that integrate
GPS, image processing and GIS on laptop computers provide
resource managers full mobility in the field and allow the rapid
collection of ground truth information. It is expected that
routine use of these techniques will lead to improvements in the
thematic accuracy of resource databases. The increased use of
GPS, image processing and GIS technologies also will allow
managers of natural resources to evaluate existing strategies
and make ecologically sound decisions.
4. ACKNOWLEDGMENTS
Research projects reported herein were sponsored by the U.S.
Department of Interior, National Park Service (NPS) through
Cooperative Agreement # 5280-4-9006. The assistance of the
NPS South Florida Natural Resource Center (SFNRC),
Homestead, Florida; the Florida Department of Environmental
Protection, St. Petersburg, Florida; the South Florida Water
Management District, West Palm Beach, Florida; SPOT Image
Corporation, Reston, Virginia; Survey Resources International,
Inc., Houston, Texas; Eastman Kodak Company, Rochester,
New York; and Mr. William Harris of Global Satellite Surveys,
Decatur, Alabama is gratefully appreciated, as are the efforts of
the many CRMS personnel who have contributed to these
projects.
5. REFERENCES
Cowen, D.J, JR. Jensen, P.J. Bresnahan, G.B. Ehler,
D.Graves, X. Huang, C. Wiesner and H.E. Mackey Jr., 1995.
The design and implementation of an integrated geographic
information system for environmental applications, Photo-
grammetric Engineering and Remote Sensing, 61(11): 1393-
1404.
Davis, S.M. and J.C. Ogden, (Eds.), 1994. Everglades: The
Ecosystem and its Restoration, St. Lucie Press, Delray Beach,
Florida, 826 p.
Remillard, M. and R. Welch, 1993. GIS technologies for
aquatic macrophyte studies: Modeling applications, Landscape
Ecology, 8(3): 163-175.
Welch, R., M. Remillard, and R. Doren, 1995. GIS database
development for South Florida’s National Parks and Preserves,
Photogrammetric Engineering and Remote Sensing, 61(11):
1371-1381.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996
