Claudio Dupas 
  
SAR AND LANDSAT TM 
IMAGE FUSION FOR LAND COVER CLASSIFICATION 
IN THE BRAZILIAN ATLANTIC FOREST DOMAIN 
Claudio Azevedo Dupas 
ITC, PO Box 6, 7500 AA Enschede, The Netherlands 
cadupas Q hotmail.com 
KEY WORDS: Synthetic Aperture Radar (SAR), Landsat TM, Orthorectification, Image fusion, Gaussian maximum 
likelihood classification, Error matrix. 
ABSTRACT 
This paper demonstrates the applicability of Landsat TM and SAR image fusion for land cover classification in the 
Brazilian Atlantic forest domain. The Atlantic forest is considered one of the most threatened of the world's rain forest. 
Although Landsat TM has been used as an efficient tool for tropical forest monitoring, several problems remain. First, 
cloud cover is a constant problem in the tropics, which limits the vegetation cover assessments by the optical sensor. 
Second, forest, regrowth and clearings are not easily differentiated. 
Recently, imaging radar satellites have been introduced to map natural resources. With long wavelengths, radar's 
radiation is not reflected or absorbed by clouds or haze, thereby allowing more frequent and systematic assessments of 
land cover changes and deforestation. The same principle allows penetrating in the canopy to assess data on the trunks 
level, which increases the potential of distinction between different stages of regrowth. 
Two different SAR images were fused with a Landsat TM image using two different image fusion techniques. Image 
classification was performed and the classification accuracy was assessed. The classification accuracy from each fused 
image was compared the one from the Landsat TM. The best results were achieved by the image originated from 
combining the JERS-1 image with the Landsat TM image using the IHS cylindrical transformation. The results suggest 
that the image fusion Landsat TM / SAR could be an important alternative for land cover mapping in the Brazilian 
Atlantic forest domain. 
1 INTRODUCTION 
The Atlantic Forest, or *Mata Atlantica', once covered more than a million square kilometers along the Brazilian coast. 
Its ‘anthropogenic disturbance’ began as soon as the colonists arrived, almost five centuries ago. The timber of 
‘Pau-brasil’ (Caesalpinia echinata), commercially prized, was the forest's first major product and was logged almost to 
extinction. Afterwards, deforestation for sugarcane cultivation, mining, coffee, banana and rubber plantations also 
occurred as the settlers moved inland. This region is now the major agricultural and industrial area in Brazil and 
includes in its surrounding area over 100 million inhabitants. As a result, deforestation is still occurring and only 8.3 
percent (SOS Mata Atlantica ef al., 1998) of the forest original area remains intact, irregularly distributed over 
fragments of different sizes, shapes and forest formations. ‘These last vestiges of Atlantic forest are now considered to 
be one of the most threatened of the world's rain forests, sharing this distinction with the remains of the tropical forest in 
Madagascar’ (IUCN, 1996). Recognizing its singularity and importance, in 1991 UNESCO declared the Atlantic forest 
as being a high priority area to create new biosphere reserves. 
Although there are a considerable number of conservation areas in the Atlantic forest, the total area covered by parks, 
reserves and ecological stations amounts to only 3000 sq. km of the estimated 100,000 sq. km of actual forest area 
(IUCN, 1996). Based on these numbers, it’s reasonable to say that the preservation of its remaining cover can only be 
achieved if new conservation areas are created. In order to indicate which parts of this unique biome are technically and 
strategically most important to be protected in a reserve, mapping and monitoring the land cover in a systematic and 
continuous way are needed. Moreover, precise numbers on the deforestation rate must be obtained. 
Recently, a project has been implemented by INPE and the NGO SOS Mata Atlantica for continuously monitoring by 
quantifying the totality of the remaining forest using Landsat TM and with a five years temporal resolution. Up to now, 
the project generated two reports covering ten Federal States for the periods from 1985 to 1990 (SOS Mata Atlantica 
and INPE, 1993) and from 1990 to 1995 (SOS Mata Atlantica ef al., 1998). Both reports pointed cloud cover as being a 
constant problem, which leaded to gaps in all the maps and even to cancellation of the Bahia State map update. 
  
96 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B1. Amsterdam 2000. 
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