The South Florida Satellite Image Map Series: A Tool for Research, Monitoring,
and Education
John W. Jones
Jean-Claude Thomas
Angel Gonzalez
U.S. Geological Survey, Eastern Region Geography, Reston, VA
Heather Henkel
U.S. Geological Survey, Center for Coastal and Watershed Studies, St Petersburg,
FL
Satellite image maps provide an empirical foundation for the study of the
temporally dynamic and spatially complex nature of Everglades land surfaces.
They help laboratory and field scientists plan instrument placement and field
experiments. They provide spatial context for the interpretation of data related to
Everglades research, modeling, and restoration activities. They constitute baseline
data for Everglades monitoring. Several satellite image maps covering the region
south of Lake Okeechobee have been distributed as USGS Miscellaneous
Investigations Series publications (Jones and Thomas 2001, Thomas and Jones
2002, Jones and Thomas, in review). Each map (e.g., fig.1) covers the largest area
possible given high-quality, mass-printing limitations for 1:100,000 scale
National Mapping Accuracy Standards. Every map was designed to meet a variety
of needs. For example, the first publication (fig. 2) was constructed with both
scientists and the general public in mind. Driven by research requirements, the
boundaries of its western sheet encompass a focus area for hydrologic modeling.
The eastern sheet allows the general public to view the urban development of the
Atlantic Coast adjacent to the Everglades wetlands and contains descriptions of
the map’s development and interpretation in terms that can be understood by a
broad spectrum of readers. Together, these two parts serve as an intuitive
backdrop for discussion of important environmental, economic, and social issues.
They allow viewers to understand some of the interrelationships among
Everglades wetland condition and agricultural, industrial, and residential
activities. Some environmental features like the impact of fires and the status of
nutrient removal areas are obvious (fig 1). Others require closer image map
inspection. For example, visual comparison of the first and third maps in the
series uncovers subtle, high frequency variations. Their source images were
collected only 9 days apart (i.e., 2/5/00 and 1/27/00, respectively). However,
water level data recorded in an area of image overlap show that water levels
dropped approximately 8cm over that short period (fig. 3), creating impacts that
Nutrient
removal
areas
Recent burn
areas
Figure 1 A thumbnail view of the Northern Everglades image map in the series of 1:100,000 scale
image maps distributed in both printed and digital forms as part of the USGS Miscellaneous
Investigations Series.
One area of
overlap among
image maps
where impacts
of changes in
water levels
are obvious.
Figure 2 A mosaic of the two Southern Everglades image maps in the series. While this area is
printed on two 1:100,000 scale maps, the maps were combined before digital distribution.
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Figure 3 Recorded stage for one Big Cypress National Preserve station number 8.
are detected with careful examination of full-resolution renditions of the image
maps.
The creation of such information-rich satellite image maps required a great deal of
research and forethought. Multivariate statistical analysis was combined with the
knowledge of remote sensing physics to select a combination of satellite
measurements that yields desired colors, minimizes adverse impacts of the Earth’s
atmosphere on image clarity, and maximizes contrasts and information content.
Image colors change as the data are transferred from digital to paper formats.
Therefore, previous experience and repeated trials were used to further digitally
manipulate the data to produce visually appealing, easily interpreted colors across
all final image maps. Project research also developed a mathematical procedure to
sharpen urban and other features by merging multiple satellite image data sets. To
make the image maps as useful as possible in the field, the classroom, and the
conference room, they’ve been made widely available in a variety of formats.
Printed maps can be obtained at low cost through the U.S. Geological Survey’s
Earth Science Information Center (1-800-ASK-USGS). In addition, following
Library of Congress policies, printed image maps were scanned with sufficient
resolution to reproduce them to scale without loss of information. Also, these
output files were sub-sampled for other uses. Finally, one file for each map was
converted to Geotiff format for use in Geographic Information Systems. Each
map has been featured on the South Florida Information Access website upon
publication, where all digital files are freely available (sofia.usgs.gov).
References
Jones, John W. and Jean-Claude Thomas, 2001. Southern Everglades.
Miscellaneous Investigations Series Map I-2742 (Eastern and Western Sections).
Thomas, Jean-Claude and John W. Jones, 2002. Northern Everglades.
Miscellaneous Investigations Series Map I-2756.
Jones, John W. and Jean-Claude Thomas, in review. Big Cypress – Pine Island.
Miscellaneous Investigations Series Map.
Contact: John W. Jones, 521 National Center, Reston, VA. 20192. Phone:
703/648-5543, Fax: 703/648-4063, email: jwjones@usgs.gov