EVALUATION OF SIR-C/X-SAR DATA FOR THE IMPROVEMENT OF GEOMORPHOLOGY AND SOIL 
MAPS IN ACRE STATE, BRAZIL 
Hermann J. H. Kux (*) 
Joäo Roberto dos Santos (*) 
Manfred Keil (**) 
Dominic R. Scales (**) 
(*) INPE - Instituto Nacional de Pesquisas Espaciais, DSR 
Caixa Postal 515 - 12.227-010 Sáo José dos Campos, SP, Brazil 
Tel.: +55-123-25-6426, Fax: +55-123-21-8743, E-mail: hermann@ltid.inpe.br 
(**) DLR - Deutsche Forschungsanstalt für Luft- und Raumfahrt, DFD, Münchener Str., 20 - D-82234 Wessling/ 
Oberbayern, F.R. Germany 
Tel.:+49-8153-281377, Fax:+49-8153-281843, E-mail: keil@dfd.dir.de 
Commission VII, Working Group 3 
KEYWORDS: Geography, SAR Analysis, Amazonia. 
ABSTRACT 
An evaluation of a X-SAR scene from the SIR-C mission is made with special interest for the improvement of 
geomorphology and soil maps in Acre State, SW Amazonia, Brazil. Potential operational applications of X-SAR data 
are discussed, indicating the possibility of the use of relatively straightforward procedures and methods. 
1. INTRODUCTION 
Experience with the analysis and evaluation of airborne 
X-SAR data in the tropics, specially for natural resources 
mapping, go back to the late 60's and early 70's. There 
are many good examples on the utility of these imaging 
systems, after aerial surveys performed in remote areas of 
Asia (Indonesia, Borneo), Africa (Nigeria, Togo, Ivory 
Coast) and Latin America (Nicaragua, Colombia, 
Venezuela and Brazil) (Koopmans, 1983, Trevett, 1986). 
Brazil established, worldwide the most ambitious 
mapping program of natural resources, setting up Projeto 
Radam. During the early 70's the X-SAR GEMS 
(Goodyear Environmental Mapping System), mounted in 
a Caravelle aircraft imaged the entire country to produce, 
among others, semi-controlled radar mosaics, to be 
evaluated for Geology, Geomorphology, Soils, 
Forest/Landuse, and Potential Landuse by Brazilian 
scientists (Bittencourt Neto, 1979). The results are 
available as reports and thematic maps, at 1:1,000,000 
SCALE, for the entire country. 
Since 1990, there is a cooperation program between 
(German Aerospace Research Establishment) and INPE 
(National Brazilian Institute for Space Research) in Acre 
State, SW Amazonia, to evaluate the usefulness of 
different sensor systems to map the dynamics of changes 
in the tropical rainforest, due to human interference 
(Hônsch 1993, Kux et al., 1993, 1995, Keil et al. 1995a, 
394 
1995b). In the frame of this cooperation program, testsite 
Acre was selected as a project area for ecology and 
tropical rainforest monitoring, using multifrequency and 
multipolarization SAR data of the SIR-C (Shuttle 
Imaging Radar)/X-SAR mission. Different datasets from 
different sensor systems TM-Landsat, ERS-1, airborne C- 
band SAR) have been used for comparison with 
multifrequency (L, C and X-band) and multipolarization 
(HH, VV, HV, VH) data of this mission. 
In this context, the objective of this paper is to analyz 
the information content of X-SAR data separately and to 
discuss on how existing geomorphologic and soil maps of 
this region could be improved. A companion paper, 
presented at this Symposium by Santos et al. (1996) 
refers to the joint analysis of SIR-C, L band, and TM- 
Landsat data to characterize the land cover of an 
adjoining area. 
2. MATERIALS AND METHODS 
The X-SAR scene analyzed (Fig.1) was taken in Apri 
18th, 1994, at descending orbit, VV polarization, with à 
nominal resolution of 25x25 m, and an incidence angle 
at the middle of swath, of 27.4°. The following pré 
processing was made at DLR/DFD: tone adjustment 
between near and far range, and application of a MAP 
filter, with a 3x3 window, to reduce speckle noise without 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996