D R . L. A L A N E Y R E
F l o r i d a A t l a n t i c University
B o c a R a t o n , Flu. 33432
High-Altitude Color Photos
Color and color-IR transparencies at 1 :60,000 scale were
useful for regional analysis.
HIGH
photographs of t h e
United States were declassified in 1969
ALTITUDE AERIAL
and the opportunity has t h u s opened for more
general utilization of this type of imagery. I n
October of t h a t year a NASA RB-57 overflight* a t approximately 18 k m altitude
covered a large area of South Florida, including the vicinity of T e s t Site 164 a t Boca
Raton where t h e Remote Sensing Laboratory
of Florida Atlantic University Geography
Department is located. T h e photographs included color a n d color-infrared of the entire
tri-county region of southeast Florida: Palm
Beach, Broward a n d Dade counties.
its potential for quantifying the dimensions of
regional change.
T h e imagery is in t h e form of 228 m m b y
228 m m duplicate positive transparencies
which were projected through a Bessler Overhead Projector (modified for aerial roll-film
use) onto a rear-view screen. Closer examination b y magnifier was accolnplished using a
fluorescent daylight tube illumination system
made in the laboratory. Under ideal laboratory conditions, resolution of these color and
color-infrared transparencies is in t h e range 4
meters. Each transparency covers a n area of
22.5 km2 a t a scale of 1:60,000. (Zeiss R M K
ABSTRACT:
Declassified high-resolution color and color-infrared photographs
from 18 k m altitude provide a new and useful tool for regional analysis. Because under ideal laboratory conditions a ground resolution of 4 meters i s combined w i t h a coverage of 22.5 k m Z o n each transparency, both macro-scale patterns and a high degree of detail are capable of accurate analysis. Use of this
imagery to record 13 years of change in a rapidly deoeloping area of south
Florida suggests that the imagery has m a n y advantages for a wide range of objectives.
This region has experienced exceptionally
far reaching changes in recent years. I t includes one of t h e most rapidly growing urbanized areas in North America, concentrated
along t h e Gold Coast b u t also extending increasingly inland. A t t h e same time, i t is almost t h e only region t h a t has undergone very
substantial agricultural development on land
never before used for this purpose. South
Florida, in fact, is one of t h e last frontiers in
t h e nation for massive development on a
regional scale. T h e availability of high-altitude imagery made i t feasible to evaluate
* hi^ NASA mission was planned and directed
by Dr. James P. Latham, Principal Investigator
of NASA Test Site No. 164 and of Contract No.
14-08-001-10936 supported by the Geographic Applications Office of the U.S. Geological Survey. The
present study was conducted by the author under
this contract.
30/23 Aerial Mapping Camera was used t o
record t h e imagery.)
Attention has been focussed on three main
aspects of change in t h e region, which in f a c t
overlap. These are:
1. The transformation of the southeast Florida
wetlands, popularly though not entirely accurately known as the Everglades,
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T h e limits of all these three elements in t h e
regional pattern were known from d a t a obtained in 1956 b y the U.S. Geological Survey
which used both photogrammetry and t h e
Corps of Enginground surveys of t h e
neers 1:25,000 quadrangles. ' h e development analyzed therefore covered the period of
13 years from 1956 to 1969.
I n 1956 there were 9750 km2 of undrained
wetlands within t h e tri-county region. During
1149
TABLE
I. REGIONAL
ANALYSIS
OF DADE,
BROWARD
AND PALMBEACHCOUNTIES
FLORIDA
USING1 8 - ~COLOR
~ .
AND COLOR-INFRARED
PHOTOGRAPHY
Major Changes 1956-1969
km2
Undrained wetlands, 1956
Drained 1956-1969
(a) Utilized for 1. Sugar Cane
2. Truck farming
(So. Dade)
3. Grassland
4. Citrus and undifferentiated
Total
Agriculture
5. Sand and Gravel
Quarries
6. Urban expansion
7. Military, recreation,
utilities
(b) Unutilized or undifferentiated
Undrained wetlands, 1969
(a) Water Conservation Areas
(b) Everglades National Park (Dade
Co.)
(c) Indian Reservation
(d) Corbett Wildlife Area
(e) West Palm Beach Water Retention Area
(f) Unreserved wetlands
Urban built-up area, 1956
Expansion 1956-1969
Urban built-up area, 1969
Total area of Dade, Broward and Palm
Beach Counties
I
374
1032
1406
13,400
t h e thirteen years t h e drainage a n d water
regulation work of t h e U.S. Corps of E n gineers and t h e operations of t h e Central a n d
Southern Florida Flood Control District with
headquarters a t West Palm Beach have reduced this b v 2600 km2 t o 7150 km2. Of this
newly drained area, 6 percent has been built
over, 68 percent has been developed for
agriculture a n d 2 percent has been p u t t o all
other uses (airfields, mining, recreation, etc.) ;
24 percent was undeveloped a s of October
1969 (Table 1).
T h e remaining 7150 km2 of undrained wetlands a r e not homogeneous in character, a n d
t h e color-infrared transparencies were very
useful in distinguishing various subtypes.
Very striking is t h e pattern formed b y t h e
three W a t e r Conservation Areas (Figure 1).
These a r e very large bodies of shallow freshwater, totalling 3275 km2in all, impounded b y
levees, a n d a r e used to control t h e natural
flow of water from Lake Okeechobee southwards to t h e Gulf of Mexico, Florida B a y a n d
t h e Atlantic Ocean, mainly t o prevent flooding. Sawgrass a n d algae, t h e vigorous growths
of which occur throughout t h e W a t e r Conservation Areas, can be noted by characteristic streaks a n d blotches of red o n t h e colorinfrared (Figure 1). Variations i n d e p t h ean
also be detected where stretches of open water
occur.
A second division of existing undraincd
wetland comprises 2122 km2 of reserved areas
under various authorities. These include t h a t
portion of t h e Everglades National P a r k
within D a d e County, t h a t p a r t of t h e Sem-
FIG.1. Water Conservation Areas have a characteristic pattern of surface water, lenticular hamrnocks
rising slightly above the water level, sawgrass and algal growth. The linear feature is a levee. (North is to
the right).
HIGH-ALTITUDE COLOR PHOTOS
inole Indian Reservation outside t h e levee of
Water Conservation Area No. 3, t h e West
Palm Beach Water Retention Area and t h e
Corbett Wildlife Area. T h e third division
comprises those wetland areas not utilized for
specific purposes in October 1969. T h e boundaries between the reserved areas and the undeveloped lands are often quite distinct on t h e
imagery even where their physiographic
characteristics are similar.
If t h e color and color-infrared photography
are used together, a very detailed picture of
this semi-aquatic environment can be obtained, a s well a s the broad regional physiographic changes from north to south a n d
from the d r y coastal ridge inland. This unique
environment ranges from marine and brackish
mangrove swamp in t h e extreme south a n d
southeast, through sawgrass with slightly
elevated tree hammocks and intervening
sloughs, to t h e so-called Florida karst in t h e
north. This last is a curious marshland topography with many low, circular solution features, the details of which are far more apparent from the high altitude photography
than on t h e ground (Figure 2).
T h e expansion of agriculture, almost all b y
occupance of drained wetland, can be interpreted at a macro level. Four principal
types of development can be detected. These
are :
(1) sugar cane, (2) vegetable and truck
farming, (3) citrus, and (4) grassland.
T h e signatures of the first two o n t h e
photography are very distinctive, and the expanded acreages of each easily calculated. Between 1956 a n d 1969 t h e area under sugar
cane increased b y 1207 km2, all of i t reclaimed
from drained Everglades muckland. This expansion is the direct result of the Cuban
situation when sugar supplies to t h e United
States were curtailed after 1959. T h e industry
is highly mechanized although both domestic
migrant and West Indian labor plays a significant role. Major citrus development (also
in t h e form of large-scale enterprises) has
entered the area, mainly in Palm Beach
County, since 1956 on drained wetland underlain b y t h e Florida karst topography. Some
citrus developments in a very early stage were
difficult to differentiate from some other possible land uses. For this reason citrus had t o
be included with a n undifferentiated category
in Table 1. T h e truck farming is primarily in
southern Dade County. Here, although 85
km2 were taken in from the wetlands, 212 km2
were lost to urban development, a trend
which is continuing.
T h e fourth category, grassland, posed a
1151
FIG.2. The Florida karst topography is easily
recognized on the 18-lun photography. Variations
in relief are within a range of a meter or two. Algal
growth and in some cases eutrophication of the
s be identified. (North a t top).
karst ~ o n d can
difficult problem of interpretation. There are
three types of grass cover in this region, all
derived from drainage of the wetland. These
are pasture, sod a n d natural herbaceous cover
developing from former wetland now drained
b u t unutilized. I n t h e d r y season t h e last
category would probably be distinguishable,
b u t in October the rains give a n almost uniform red t o all grasses on the color infrared.
T h e pasture is used a s open, b u t improved,
range for cattle, and the presence of faint
tracks and watering points sometimes can
give indication of this land use. Large sod
farms cultivate St. Augustine grass for trucking to gardens in nearby urban areas: from
18 km, however, this specialty is not easily
distinguishable from improved pasture or fodder crops. For the drained b u t unutilized
areas, t h e semi-aquatic sawgrass vegetation
quickly gives way to a variety of seasonal
scrub a n d bunch grasses a n d low ligneous
plants, with t h e gradual invasion of larger
shrubs a n d palmetto. Most of the unutilized
areas are being held a s speculation in anticipation of large-scale urban development. Even
immediately adjoining t h e Everglades National Park, 61 k m from Miami and 13 k m
beyond t h e present limit of suburbia in Dade
FIG. 3. Expansion on to drained wetlands is
taking place rapidly. Development proceeds by the
purchase of 640-acre square sections and their subsequent subdivision for residential use. The development at top is lower middle income whereas
diagonally southeast across the expressway is a
prestige community. (North at top).
County, land is being subdivided for sale a s
homesites. On some lands of this type, an extensive type of low-density livestock rearing
is practiced as a temporary utilization. There
were a little over 600 km2 of drained former
wetlands not visibly utilized in October 1969.
The expansion of the urban area has been
in two directions: a linear development which
has linked all the coastal townships along a
160 km section of the Atlantic shoreline into
one continuous conurbation, and a westward
expansion into the drained wetlands. The latter movement is particularly characteristic of
Dade and Broward counties. With lower altitude photography such a s the NASA 1.5 km
and 4.5 km coverage of Test Site No. 164,
considerable potential for infilling of small
plots of vacant land can be observed*, but on
the high-altitude imagery the limits and extension of the urbanization is very sharply
defined. The type and density of the development can also be estimated within reasonable
limits. From a 1956 area of 374 km2, the
Dade-Broward-Palm Beach urban complex
has exploded 280 percent in 13 years to occupy a total land area in 1969 of over 1400
km2.
One trend is of particular interest: the tendency for middle-income residential development (identified by lot size and subdivision
* See L. Alan Eyre. Three Million New Southerners: Depopulation and Migration in five southeast
states 1950 to 1968. Florida Planning and Deuelopment, Vol. 21, No. 2, February 1970, pp. 1-8.
design on the photography) to expand westwards in Broward and Dale counties' former
wetland drained by the U.S. Corps of Engineers as far as the levee of the Water Conservation Areas 1 and 2 (Figure 3). The continuous 128-km long eastern levee of the
Conservation Areas forms a unique barrier to
expansion of a major metropolitan region.
With the Everglades National Park blocking
expansion to the south, and the ocean on the
east, this island of development is hemmed in
on all sides except a t a 16-km wide neck near
Boynton Beach (Figure 4). Expansion is open
only from this point northwards. Under these
conditions i t is apparent that enormous demographic and economic pressures will be built
up during the 1970's upon the remaining
agricultural areas of the tri-county region and
westward into Collier County beyond the
Conservation Areas. More seriously, they will
also be brought to bear upon large undeveloped but ecologically vital tracts of the Ever-glades National Park.
As water is particularly emphasized on the
color-infrared, it is possible to identify the
principal features of the complex hydraulic
system operated by the Flood Control District. This vast system, which extends from
Orlando, Florida to the Keys and includes
hundreds of kilometers of canals with associated sluices, pumping stations and spillways,
maintains more or less effective control over
the entire water regime of a shallow basin
50,000 km2 in extent. From the high-altitude
photographs, the effects of pollution can be
observed upon this enormous, slow-moving
mass of water a t several places. Particularly
evident are the vivid red of water hyacinth
infestations, excessive algal growth in semistagnant areas and several major pollution
features in Lake Okeechobee. A t some localities specific effects of canalization such as silt
transportation and deposition can be noted.
In the kind of regional overview obtainable
from imagery a t this scale, i t is possible to
recognize by characteristic signatures unusual
features which occur a t widely separated localities and calculate the area they occupy.
For the region under discussion such features
include drilling rigs, missile launch sites, commercial nurseries, sand and gravel quarries,
golf courses and junk yards. Gravel pits and
golf courses both occupy an unusually large
area in the tri-county region (Figure 5).
With this October 1969 photography, covvering both an urbanized region of two million people and one of the few major agricultural developments of the past decade, its
potential for detailed spatial analysis of the
HIGH-ALTITUDE COLOR PHOTOS
1153
FIG.4. A portion of the regional analysis made of Dade, Broward, and Palm Beach counties, Florida,
from 18-km photography a t the Remote Sensing Laboratory, Florida Atlantic University. Heavy dotted
line indicates limits of drained area in 1956, with built up area solid black. Stippled, built up area 1969;
hatched, water storage; utilization of land drained since 1956 is shown,-As, sugar cane; Ag, grassland;
Ac, citrus; U, unutilized; M, Mining and quarrying.
FIG.5. Sand and gravel quarries (left) occupy 41
km2 in the tri-county area. Golf courses (right
center) are also a major land use in this region
where more than a third of the male population
consists of retirees. (North a t top).
April 1970 Census of Population is considerable. I t seems from t h e imagery t h a t t h e
great expansion of agricultural land i n Palm
Beach County has not been accompanied b y
a n y corresponding dispersal of rural settlement. N o t only is t h e development capital
intensive and associated with very large land
holdings, b u t t h e universal availability of
road transportation has enabled almost all
t h e increased population t o be accommodated
in a n d around t h e existing centers such a s
Belle Glade and West Palm Beach.
T h i s evaluation is of a preliminary nature,
a n d only o n t h e broadest scale. I t is obviously
possible t o analyze landscape with this t y p e
of photography a t a much more detailed level
t h a n t h a t reported in this particular study.
However, almost t h e only comparable tool
u p t o t h e present for providing a broad synoptic picture for regional analysis b y photogrammetry has been t h e black-and-white
photo-mosaics prepared b y t h e U.S. Department of Agriculture. Results using this new
18-km photography a r e clearly superior because of t h e degree of resolution, t h e combined
power of color a n d color-infrared interpretation, a n d t h e large area covered b y each
frame. However, t h e greatest advantage of
this high altitude imagery is undoubtedly t h e
time-saving element, because i t is possible t o
delineate and identify major geographic patof 'quare
terns Over
very rapidly.