APPLICATION OF FUSION TECHNIQUES TO (ETM+/SRTM) IMAGES TO RECOGNIZE AND INTERPRET DEPOSITIONAL LANDFORMS: AN EXAMPLE FROM THE NEGRO RIVER ALLUVIAL PLAIN, PANTANAL MATO-GROSSENSE

APPLICATION OF FUSION TECHNIQUES TO (ETM+/SRTM)IMAGES TO RECOGNIZE AND INTERPRET DEPOSITIONAL

LANDFORMS: AN EXAMPLE FROM THE NEGRO RIVERALLUVIAL PLAIN, PANTANAL MATO-GROSSENSE

Deborah MENDES1,2

Mario Luis ASSINE3

Mônica Mazzini PERROTTA2

Fabrício Aníbal CORRADINI1,4

Aguinaldo SILVA5

Abstract

The objective of this paper is to demonstrate the application of HSV fusion techniques ofde-correlated spectral bands from Landsat 7 ETM+ with NASA SRTM data for the extraction ofdrainage networks and identification of depositional and erosive landforms of Negro River fluvialplain, located in the southern Pantanal, Mato Grosso do Sul State, central-west Brazil. Thistechnique allowed a significant gain at the interpretation of landforms, as compared tointerpretation carried out using only satellite images. The landforms were highlighted in theresultant merged images with SRTM data, allowing the identification of relief features poorly evidentin satellite images. The images generated clearly showed the existence of erosive landforms,such as tributary streams and channels, degrading relict landscapes represented by ponds, similarto those of the Nhecolândia area that characterize the southern part of the Taquari fluvial megafan.The use of this technique helped to establish the chronological sequence of depositional anderosive events on the Negro River plain, showing that merged images can be successfully used tointerpret the geomorphologic evolution of alluvial plains, and a potential tool for the interpretationof other fluvial systems in the Pantanal of Mato Grosso.

Key-words: Image Fusion. SRTM. ETM sensor. Pantanal. Fluvial Systems.

1 Universidade Estadual Paulista Julio de Mesquita Filho � UNESP, Instituto de Geociências e Ciências Exatas� IGCE, Programa de Pós Graduação em Geociências e Meio Ambiente, Av. 24A, 1515, 13506-900 - RioClaro - SP, Brasil

2 Companhia de Pesquisas de Recursos Minerais � CPRM, Rua Costa, 55, 01304-010 - São Paulo - SP, Brasil.E-mail: [email protected]; [email protected]

3 Universidade Estadual Paulista Julio de Mesquita Filho � UNESP, Instituto de Geociências e Ciências Exatas� IGCE, Departamento de Geologia Aplicada, Av. 24A, 1515, 13506-900, Rio Claro - SP, Brasil.E-mail: [email protected]

4 Universidade Federal do Pará � UFPA, Campus Marabá, Folha 31, Quadra 7, Lote Especial S/N - Caixa-Postal 101, 68501-970, Marabá - PA, Brasil, E-mail: [email protected]

5 Universidade Federal de Mato Grosso do Sul � UFMS, Departamento de Ciências do Ambiente, Av. RioBranco, 1270 � 79304-902, Corumbá - MS, Brasil, E-mail: [email protected]

GEOGRAFIA, Rio Claro, v. 36, Número Especial, p. 85-95, jun. 2011.

86 GEOGRAFIA

Application of fusion techniques to (ETM+/SRTM) images to recognize andinterpret depositional landforms: an example from the Negro River

alluvial plain, pantanal mato-grossense

Resumo

Aplicação de técnicas de fusão de imagens (ETM+/SRTM) no reconhecimento einterpretação de geoformas deposicionais da planície do Rio Negro,

pantanal mato-grossense

Este trabalho tem como objetivo mostrar a aplicação de técnicas de fusão HSV de imagensde satélite do sensor ETM+ do LANDSAT 7 com dados SRTM da NASA na extração de redes dedrenagem e na identificação de geoformas deposicionais e erosivas da planície fluvial do rio Negro,situado na área sul do Pantanal Mato-Grossense. Com a aplicação da técnica utilizada, houveganho significativo em relação à interpretação realizada unicamente com imagens de satélite, asgeoformas foram ressaltadas nas imagens resultantes da fusão com dados SRTM, o que permitiuidentificar feições de relevo pouco evidentes nas imagens de satélite. As imagens geradasmostraram com bastante clareza a existência de geoformas erosivas, tais como vazantes e canaistributários atuais, desfigurando paisagens relictas representadas por lagoas semelhantes às daNhecolândia, que caracterizam a porção sul do megaleque do Taquari. A utilização da técnicacontribuiu para estabelecer a sucessão de eventos deposicionais e erosivos na planície do rioNegro, mostrando que a fusão de imagens pode ser utilizada com sucesso na interpretação daevolução geomorfológica de planícies fluviais, sendo ferramenta potencial para a interpretaçãode outros sistemas fluviais do Pantanal Mato-Grossense.

Palavras-chave: Fusão de imagens. SRTM. Sensor ETM. Sistemas Fluviais. Pantanal.

INTRODUCTION

The Pantanal Mato-Grossense is an extensive sedimentary plain with an area ofabout 138,000 km² and altitudes varying between 80 m and 190 m located in the States ofMato Grosso and Mato Grosso do Sul (SILVA; ABDON, 1998). It is located in the UpperParaguay River Basin, which is bordered from north to south by the Parecis, Guimarães,Taquari-Itiquira, Maracajú-Campo Grande and Bodoquena plateaus, and to the west by theresidual relief of Urucum-Amolar plateau (Figure 1). The Paraguay River is composed ofvarious fluvial mega-fans with its drainage basins in the neighboring plateaus. The Taquaririver megafan, which is the largest one, occupies approximately 40% of the Pantanal areaand it is easily recognized in satellite images (BRAUN, 1977; ASSINE; SOARES, 1997; ASSINE,2005).

The Pantanal is a heterogeneous sedimentary plain, because its landscape showsdifferent shapes, reflecting morphological features of different environments which makesup this depositional system, filling up the basin since the Pleistocene. The surface of Pantanalshows both active and relict relief. The characterization of these morphological featuresshould be the first step for the interpretation of the processes responsible for the origin ofthe actual landscape and, as highlighted by HORTON (1945), it is the basic assumption forthe paleogeographic reconstitution and the formulation of evolutionary models.

Landforms in macro- and mega-scale, especially in flat and/or difficult areas to access,are very easily seen by remote sensing data and respective enhancement methods. In thecase of Pantanal Mato-Grossense, images with higher resolutions allowed the recognition ofmorphological features, until recently, not seen on available images. Furthermore, theavailability of altimetry data, collected by C-band SAR from the Shuttle Radar TopographicMission (SRTM), which supplied in part the lack of topographic data from the Pantanal,provided a better understanding of various relief aspects (ZANI et al., 2009).

In this paper, the use of a fusion technique aims to explore the spectral informationof ETM+ data enhanced by de-correlation and altimetry data of SRTM image, integrated in

87Mendes, D. / Assine, M. L. / Perrota, M. M. /

Corradini, F. A. /Silva, A.v. 36, Número Especial jun. 2011

only one product. The behind this procedure was to highlight the geomorphic features ofNegro River, its modern or ancient distributaries and tributaries and its drainage patterns,and also to interpret its role in the modeling and evolution of the Negro River fluvial plain.

STUDY AREA

The Negro River shows changes in its fluvial style along its course from its sources toits confluence with the Paraguay River (MENDES; ASSINE, 2010).

The drainage basin, sculptured in the Maracaju-Campo Grande plateau, is locatedsoutheast from the Pantanal wetland. At the Pantanal entrance, the river forms a fluvial fan,where active and abandoned depositional lobes can be identified (CORDEIRO et al., 2010).

As with many rivers thata form fluvial fans as they enter the Pantanal basin, theNegro River also flows in a meandering belt that is entrenched within a valley cuttingthrough ancient depositional lobes that are apparent in terraces.

In spite of forming fluvial fans at the Pantanal entrance, the Negro River differssignificantly from other Paraguay tributaries because, downstream, the river flows in ameander belt located between fluvial megafans, being the base level for the Taquari (to theNorth) and Aquidauana and Taboco fluvial fans (to the South) (ASSINE, 2003).

The middle river course section, which comprises the fluvial fan and the meanderbelt, is investigated in this paper. It is located between the geographical coordinates S 19°00' to S 19° 45� and W 55° 00' to W 56° 00'.

88 GEOGRAFIA



Figure 1 � Map of the Upper Paraguay river indicating diverse plains whichconstitute the depositional system of Pantanal Mato-Grossense (modified by

ASSINE, 2003). The study area is indicated by a red rectangle



MATERIALS AND METHODS

To visualize the modern and ancient depositional forms, images from the ETM+ sensoraboard Landsat 7 satellite were processed (http://www.dgi.inpe.br/CDSR/ of the NationalInstitute for Space Research � INPE), referring to the following Orbits/Points (dates): 225/073 and 225/074 (01/08/2001), 226/073, 226/074 (08/08/2001) and 227/073 (30/07/2001).The software used in this paper was ENVI 4.6.1 and ArcGIS 9.3.

The images from the ETM+ sensor were geo-referenced taking as a reference theGeoCover2000 mosaic, for UTM, Datum WGS84, zone 21S. After this procedure, a mosaicwas made, and a 7R4G3B composition was enhanced by de-correlation to remove thecorrelation between the bands and increase the variance of the color composition (MATHER,2004). These bands are located within the electromagnetic spectrum, respectively, in shortwave infrared, near infrared and visible portion. In the composition chosen the blue colorrepresents the water bodies (with suspension sediments), the green color represents thevegetation and the purple color represents the exposed sandy red soils.

SRTM images were obtained from http://srtm.csi.cgiar.org/ of the Consultative Groupfor International Agriculture Research - Consortium for Spatial Information, CGIAR-CSI,fourth edition. SRTM is a cooperative project between the National Aeronautics and SpaceAdministration (NASA) and National Imagery and Mapping Agency (NIMA) of the UnitedStates Department of Defense, the German Aerospace Center (Deutsches Zentrum für Luft-und Raumfahrt � DLR) and the Italian Space Agency (Agenzia Spaziale Italiana � ASI). Thepurpose of the SRTM is to acquire a digital elevation model between latitudes N 60° and S56°, totaling approximately 80% of the Earth�s surface (FARR; KOBRICK, 2000). SRTM usestwo synthetic aperture radars, C-band SAR system (Wavelength 5.6 cm) and X-band system(X-RADAR=3.1 cm). NASA Jet Propulsion Laboratory (JPL) was responsible for the C- bandSAR (FARR et al., 2007).

In quantitative terms, cartographic products derived from SRTM data are sampled ina grid of 1 x 1 arc-second (approximately 30 x 30 m in low to middle latitudes), with linearvertical absolute error less than 16 m, linear vertical relative error less than 10m, circularabsolute geo-location error less than 20 m and circular relative geo-location error less than15 m. (FARR et al., 2007).

However, the models in C-band with 3 x 3 arc-second (approximately 90 x 90m) areavailable for the South American continent. As such, the images were converted to UTMcoordinates and the pixels interpolated from 90 to 30 m, with cubic convolution re-sampling.It is also possible to obtain refined data for 30 m from SRTM for all Brazilian territory onTOPODATA project site (http://www.dsr.inpe.br/topodata). Afterwards, in the refined digitalelevation model (DEM), obtained from the original SRTM data, the shaded relief techniquewas applied. This type of image enables better visualization of different relief in a certainregion. The image is generated from a rectangular grid on which a lighting model was appliedto determine the intensity of light reflected from a surface point, taking into considerationan artificial light source. According to Crepani e Medeiros (2004), the choice of azimuthangle and elevation angle of the light source is made by the interpreter from a qualitativeanalysis of the image, resulting from the application of these parameters. Such values mayvary according to the topographic characteristics and the orientation of the geologicalstructures of the area under study. The azimuth value of 35° and elevation value of 45°generated the best images for the interpretation of this area.

The images generated from these parameters are presented in shades of grey, andthose areas with more pronounced relief, illuminated and shaded, appear respectively in lightand dark shades, while flat areas corresponds to intermediate shades (CREPANI; MEDEIROS,2004).

90 GEOGRAFIA



To merge the images, an HSV technique from the ENVI image processing softwarewas used. HSV is an acronym for Hue, Saturation and Value. The RGB-HSV transformationseparates achromatic information (Value) and chromatic information (Hue and Saturation) ofan RGB image. In the fusion by HSV transformation method, three spectral bands of lowspatial resolution were transformed from RGB color space to HSV color space. The V componentis replaced by SRTM image, then, the reverse operation is performed returning to RGB colorspace (SCHNEIDER et al., 2003).

RESULTS AND DISCUSSION

In figure 2, it is possible to distinguish between a drainage basin (catchment area)and the alluvial plain of the Negro River; however the existing features in the plain are noteasily visualized. The analysis of the images generated by HSV fusion made it possible toseparate the drainage basin of the alluvial plain of Negro River (Figure 3).

The drainage basin of the Negro River, situated in the Maracajú-Campo Grande plateau,occupies an area of approximately 2,763 km². On the plateau, the Negro is a bedrock riverflowing over Paleozoic sedimentary rocks from Aquidauana, Ponta Grossa and Furnasformations. Near the plateau escarpment, the river cuts Ordovician-Silurian sandstones ofRio Ivaí Group, Neoproterozoic metamorphic rocks of the Cuiabá Group and associated graniteintrusions (�Rio Negro Granite�).

On the bedrock reach, the fluvial plain is controlled by NW-SE fractures. Near theentrance to the Pantanal wetland, the river flows in a meander belt 2 km wide, structurallyconstrained by a NW-SE fracture zone.

Within the Pantanal depositional domain the river acquires a distributary drainagepattern (Figure 4), recognized as a fluvial fan by Cordeiro et al. (2008). The fluvial fan islocated between gravity-dominated fans, aligned along the foot of the escarpments of theMaracajú-Campo Grande plateau, the SE border of Taquari megafan (BRAUN, 1977; ASSINE,2005) and the base of the Taboco fan located to the south (FACINCANI et al.,. 2006).

The resulting merged images from the ETM+ and DEM (SRTM) allow a better definitionof paleochannels, making it possible to identify a network of distributary paleochannels, withapex at the exit of the plateau (Figure 4), a record of changes which is occurring in thechannel since Pleistocene (ASSINE; SOARES, 2004).

From the confluence with the Anhumas stream, the river deflects to the SW andflows bordering the Taquari mega-fan, thus defining the peripheral drainage of the ancientNegro river fluvial fan. Downstream, the channel becomes narrower, its sinuosity is reduced,bifurcation occurs and the river loses its water to the plain (Figure 5).

The plain widens originating a large wetland, flooded for the most part of the year,where the river channel progressively loses its identity. It is not an active depositional area,because the fluvial sedimentary load is low and there are no recent depositional landforms.The images generated reinforce this interpretation, showing that the wetland is in a wideand shallow valley, cutting a landscape characterized by the presence of small circularponds similar to those of the Nhecolândia (Figure 5).

After the confluence with the Santa Clara, the Negro River deflects to W-NW, flowingbetween the Taquari (north) and the Aquidauana (south) fluvial megafans. The river meandersin a aggradation fluvial plain which is very prominent in the images generated by HSV fusion(Figure 6). For about 50 km, the Negro River drains the water from the southern portion ofthe Taquari megafan, crossing the typical landscape of ponds at the fringe of Nhecolândia.



Figure 2 � ETM+ sensor image, 7R4G3B, dated July/August 2001

Figure 3 � The merged image of HSV from the ETM+ Landsat 7 data (7R4G3B, July/August 2001) with DEM (applied relief shading) from SRTM. The figure shows

areas with different geomorphologic compartments of the Negroriver plain, presented in detail in figures 4, 5, and 6

92 GEOGRAFIA



Figure 4 � Distributary paleochannels allow us to delineate the Negro river fan,which flows in meandering belt section on the surface of older deposits,

characterized by the presence of distributary paleochannels. Fansdominated by gravity flows (LDFG) formed ramps at the

foot of the escarpment of the plateau to the east

Figure 5 � Negro river channel at the current distributary lobe of the fan, elongatedin a NE-SW direction. In this area, part of the southern area of the Taquari

(Nhecolândia) megafan was dissected by ebbs forming the currentlobe of the Negro river fluvial fan. Areas dominated by thepresence of the ponds remain as the relict landscape of

Nhecolândia amid the current channelsof the Negro river plain



CONCLUSION

The images resulting from the merger of the ETM+ Landsat 7 / SRTM proved to bevery useful, since individually these images do not allow clear visualization of relief features,such as distributary paleochannels and active channels, floodplains and modern tributarychannels. The data obtained from the digital elevation model may mask the limits of thedepositional forms and morphological features of the Negro River plain, impairing thegeomorphologic interpretation.

HSV fusion using shaded relief as a textural component, proved to be a great tool forthe identification of relict distributary networks, formed in different paleoclimatic conditions.The images obtained enabled a better visualization of drainage channels, possibly associatedwith geological structures.

The images highlighted important geomorphic features of the fluvial plain, such asmeander belt in the upper fan, entrenched on deposits of abandoned depositional lobes, aswell erosive channels, present in the lower fan, that are dissecting the relict Nhecolandialandscape characterized by ponds and salines.

The use of the technique helped to recognize depositional and erosional events inthe Negro River plain, showing that image fusion can be successfully used in fluvialgeomorphology, being a potential tool for the interpretation of other fluvial systems presentwithin the Pantanal wetland.

Figure 6 � The Negro river channel after the Santa Clara Ebb confluence, startsflowing in the plain in a WNW-ESE direction, river system of the fluvial plains

located to the north and to the south. In this compartment, the channelacquires a meandering pattern which changes anastomosed to the

west as it enters a tectonically more subsidence compartment

94 GEOGRAFIA



ACKNOWLEDGEMENTS

The authors are thankfull to CPRM for the agreement to Deborah Mendes to developher PhD dissertation at Unesp; to FAPESP for supporting this research (07/55987-3); toCNPq for grants to Mario Luis Assine.

REFERENCES

ASSINE, M. L.; SOARES, P. C. Quaternary of the Pantanal, West-Central Brazil. QuaternaryInternational, v. 114, n. 1, p. 23-34, 2004.

ASSINE, M. L. Sedimentação na Bacia do Pantanal Mato-Grossense, Centro-OesteBrasil. 2003. Tese (Livre Docência) - Instituto de Geociências e Ciências Exatas, UniversidadeEstadual Paulista, Rio Claro, 106 p.

ASSINE M. L. River avulsions on the Taquari megafan, Pantanal wetland, Brazil.Geomorphology, 70 p. 257-371, 2005.

BRAUN, E. H. G. Cone aluvial do Taquari, unidade geomórfica marcante na planície quaternáriado Pantanal. Revista Brasileira de Geografia, v. 4, n. 39, p. 164-180, 1977.

CORDEIRO, B. M.; FACINCANI, E. M.; PARANHOS FILHO, A. C.; BACANI, V. M.; ASSINE, M. L.Compartimentação geomorfológica do leque fluvial do rio Negro, borda sudeste da Bacia doPantanal (MS). Revista Brasileira de Geociências, v. 40, n. 2, p. 175-183, 2010.

CREPANI, E.; MEDEIROS, J. S. Imagens fotográficas derivadas de MNT do projeto SRTMpara fotointerpretação na geologia, geomorfologia e pedologia. INPE-11238-RPQ/761.Publicações. São José dos Campos: INPE, 2004. 39 p.

FACINCANI, E. M.; ASSINE, M. L.; SILVA, A.; ZANI, H.; ARAÚJO, B. C.; MIRANDA, G. M.Geomorfologia fluvial do leque do rio Aquidauana, borda sudeste do Pantanal, MS. In:SIMPÓSIO DE GEOTECNOLOGIAS NO PANTANAL, 1. Anais... Campo Grande: Embrapa, 2006.p. 175-181.

FARR, T. G.; KOBRICK, M. 2000. Shuttle Radar Topography Mission produces a wealth ofdata. Eos Transactions, American Geophysical Union, v. 81/82, p. 583-585, 2000.

FARR, T. G.; ROSEN, P. A.; CARO, E.; CRIPPEN, R.; DUREN, R.; HENSLEY, S.; KOBRICK, M.;PALLER, M.; RODRIGUEZ, E.; ROTH, L.; SEAL, D.; SHAFFER, S.; SHIMADA, J.; UMLAND, J.;WERNER, M.; OSKIN, M.; BURBANK, D.; ALSDORF, D. The Shuttle Radar Topographic Mission.Reviews of Geophysics, v. 45, 2007.

FREITAS, D. M., MATOS, F. L. C. C.; SILVA, M. C. Fusão de imagens CBERS-2B com SAR/SIPAM para identificação de desmatamento na região amazônica. In: SIMPÓSIO BRASILEIRODE SENSORIAMENTO REMOTO, 14. Anais... Natal, Brasil. 2009. INPE, p. 2025-2032, 2009.

HORTON, R.E. Erosional development of streams and their drainage basins: hydro-physicalapproach to quantitative morphology. Bulletin of the Geological Society of America, v.56, n. 3, p. 275-370, 1945.

MATHER, P. Computer processing of remotely-sensed images. Nova York: John Wiley,324 p., 2004.

MENDES, D.; ASSINE, M. L. Estilos fluviais do rio Negro no Pantanal Matogrossense. In:CONGRESSO BRASILEIRO DE GEOLOGIA, 45. Anais... Belém, 2010, CD-ROM.

SILVA, J. S. V.; ABDON, M. M. Delimitação do Pantanal Brasileiro e suas sub-regiões. PesquisaAgropecuária Brasileira, v.33, Número Especial, p.1703-1711, 1998.



SCHNEIDER, M.J.; BELLON, O.R.P.; ARAKI, H. Experimentos em fusão de imagens de altaresolução. Boletim de Ciências Geodésicas, v. 9, n. 1, p. 75-88, 2003.

ZANI, H.; ASSINE, M. L.; SILVA, A.; CORRADINI, F. A.; KUERTEN, S.; GRADELLA, F. S.Geoformas deposicionais e feições erosivas no Pantanal Mato-Grossense identificadas porsensoriamento remoto. Geografia, v. 34, número especial, p. 643-654, 2009.

Documents

APPLICATION OF FUSION TECHNIQUES TO (ETM+/SRTM) IMAGES TO RECOGNIZE AND INTERPRET DEPOSITIONAL LANDFORMS: AN EXAMPLE FROM THE NEGRO RIVER ALLUVIAL PLAIN, PANTANAL MATO-GROSSENSE