MONITORING TROPICAL FOREST FROM SPACE: THE PRODES DIGITAL PROJECT
D. M. Valeriano, E. M. K. Mello, J. C. Moreira, Y. E. Shimabukuro, V. Duarte,
I. M. e Souza, J. R. dos Santos, C. C. F. Barbosa, R. C. M.de Souza
National Institute for Space Research (INPE)
C.P. 515-CEP 12210-970. Säo José dos Campos, SP. Brazil
e-mail:(dalton, kalil, yosio, valdete, iris, jroberto)@dsr.inpe.br
(moreira, claudio, cartaxo)@dpi.inpe.br
Commission VII, WG VII/3 Integrated Monitoring Systems for Resource Management
KEY WORDS: Terrestrial, Monitoring, Land Use, Change Detection, Segmentation, Classification, Forestry, GIS
ABSTRACT:
This paper presents the results of a new methodological approach to identify and to estimate deforested areas. The work refers to the
PRODES DIGITAL PROJECT, which develops an automatic procedure to analyze satellite data, using the techniques of Linear
Spectral Mixture Model, Image Segmentation and Classification by regions, that are available on software SPRING
(GEOREFERENCED INFORMATION PROCESSING SYSTEM), a state-of-the-art GIS and remote sensing image processing
system with an object-oriented data model, which integrates raster and vector data representations in a single environment.
1. INTRODUCTION
PRODES (Monitoring the Brazilian Amazon Gross
Deforestation) is the largest forest monitor project in the world,
based on orbital remote sensing.
For many years, the NATIONAL INSTITUTE FOR SPACE
RESEARCH (Ministry of Science and Technology) has been
promoting the interpretation of images provided by the U.S.
LANDSAT satellite to monitor the evolution of the extent and
rate of gross deforestation in the Brazilian Amazon (Figure 1).
Due to the geometric problems faced during the development of
the manual interpretation of multi-temporal TM images (image
hardcopies with different scales, overlays digitizing/scanning,
complexity of deforestation pattern), the availability of these
deforestation maps in a digital format has been restricted to
some areas.
Over the last years, an effort to find a methodology to overcome
this problem has been successtul (Mello et al., 2003 and
Moreira ct al., 2003).
The digital image analysis is an alternative to perform this task.
However, the conventional digital classification using a pixel by
pixel approach has shown to be feasible only for small (local)
areas, where is possible to have a good quality control of the
image classification.
For large areas, as the ones studied by PRODES, two factors
had been restricting the digital analysis of TM images: lack of a
reliable image classifier and the huge amount of disk space
required to process several TM scenes.
With the increasing capacity of computers in terms of
processing and storage, the development of a methodology to
study large areas using digital techniques is now possible
(Shimabukuro at al., 1998).
Data from PRODES DIGITAL PROJECT, properly
georeferenced, form a database of multi-temporal layers with
easy access and integrated with different information sources
and or computer systems (www.obt.inpe.br/prodes).
2772
Figure 1 — Brazilian Amazon - WRS-TM/LANDSAT
2. ANEW METHODOLOGICAL APPROACH
2.1 Satellite Data and Image Processing System
Amazon Brazilian WRS-TM/LANDSAT images of bands 3, 4,
and 5 were used. The Landsat TM data were resampled to à
pixel size of 60 m by 60 m resulting on an image size of 3326
pixels by 3072 lines, in order to reduce computer processing
time.
Digital Charts at 1: 100 000, edited IBGE and DSG, were used
for georeferencing the satellite images.
The GIS software package SPRING (GEOREFERENCED
INFORMATION PROCESSING SYSTEM) with basic
functions of image processing (including ‘segmentation’ and
'per-field clustering classifier’ — ISOSEG) was used
(www .dpi.inpe.br/spring). Spring is a state-of-the-art GIS and
remote sensing image processing system with an object-oriented
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