47°20'
47° 11'
IS.
6 22°03
LEGEND
1- LV
2-LR
3- PV
4- Hi
5- TE
6-LE
7 -AQ
== Main River
—~< Tributaries
Q Soil Limites
Escale
0 1 2Km
et
ESTATE OF SAO PAULO
52° 48° 44°
22°10'
Fig. 2- Study area as mapped in 1982 by field work of the IAC- Instituto Agronômico de Campinas,
published at 1:100.000.
and reflected infrared radiation. The
images were from orbit 220/75D for the
month of December. The topographic
quadrilateral of Araras (1:50,000) by the
IBGE was used as the cartographic base
for plotting information.
The digital images were processed
with the SITIM-150 system on a
microcomputer with a PROCON
projector/enlarger. The work sequence is
presented in Figure 3.
3.Analysis of the images
For selecting the subgroups of
bands for generation of the color
composites, the Jeffreys-Matusita
distance method was used, as discussed by
Swain and King (1973). The JM distance
is an appropriate technique to measure
the average separability between spectral
classes, calculated as functions of
probability density. The following
researchers implemented or applied the JM
method: Bendat and Piersol (1986),
Andrade (1985), and Paradella (1984).
This technique is a convenient
alternative for selecting the best color
composite images. The series of
interband statistical measurements of the
JM method results in a reduction of the
dimensionality, processing and redundance
of data.
In general, each class of
interest (e.g. Typic Eutrorthox) in an
image can be characterized by a function
298
of density of probability Pl (x) that
gives the values of probability densities
that the pixels x belong to a -class in
function of x. For two classes wj and
Wy, the JM distance is defined as:
2
JMij = fx {es ce) V2. -« [p309] 1/2} ax
where:
JMjj = JM distance between classes wj and
wa:
J?
Pj (x) = probability density of the pixels
belonging to class Wi;
Pix). = probability density of the pixels
belonging to class wj;
X = range of interest for the X values
The software implemented on the
SITIM system calculates the JM distances
between classes selected by the user for
all possible combinations of bands. The
output includes subsets that maximize the
JM average and minimum distance criteria.
As the method to classify the
scene, a multi-variate analysis was
applied that offers the advantage of
working with both parametric and non-
parametric data. Cluster analysis was
adopted in order to work with a group of
units characterized by diverse variables.
The result is the separation of existing
groups characterized by homogeneity