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Interpretation of structural and major drainage systems studied and interpreted by means of remote sensing techniques employing SAC-C and LANDSAT TM 5 images. South América
Roberto Torra
Departamento de Geociencias.
Facultad de Ingeniería. Universidad Nacional del Nordeste.
Güemes st No 749, H3500CBO. Resistencia, Chaco, Argentina.
roberto_torra@arnet.com.ar
Abstract
A remote sensing study of structural (tectonic assemblage) and network drainage systems of the South American continent was made. We used SAC - C raw scenes and composed .jpg “free mosaickings” of Landsat TM 5 images which were released by the Geological Survey of the United States (USGS) in your servers. We assemble the SAC-C images in graphic design programs. The LANDSAT TM 5 satellite series, which were nine scenes assembled per each digital archive were handled by means of digital image processing software. We determine the main structural lineaments, geological regional units and the principal drainage systems, including Amazonas, Orinoco, Del Plata, Paraguay, Uruguay and Paraná rivers catchments. Both visual and digital interpretations were made always helped by field works. Continental and regional studies are largely improved by using satellite images of these kinds which carry medium spatial resolution sensors. So, it is very useful for make preliminary structural and drainage interpretations helping land-use and land-management projects due to relative low cost and rapid peer review of the relief and structural framework.
Introduction
During the last four decades satellite imagery appeared (1972) as a primary tool-technique to help many human activities including most types of physical, human and environmental studies. They are strongly related to civil works due to its direct relation with the study of “sites” of medium-to-large humankind activities as civil works projects emplacements among others.
Land use, land management, forestation planning, deforestation exploitation, floodings disasters, risk erosion soils, aridification-desertification geo-indicators, large hydraulic works, “continental pipelines”, strategic dams all were embraces as well as the cattle rising and engineering civil works benefits, among others branches.
At the east and central zones of South America, the landscape is largelly characterized by widely flat and/or depressed (lowlands) as well as many medium ridges and extensive plateaus especially at the Brazil, Guyane, Suriname and Venezuela countries relief.
A conspicuous extensive “forest” named as the Amazonic Jungle and the inter-tropical wrapper robust vegetation jungles (sometimes called as “Jungas” as in the foreland foothill near the orogen semi-low ridges margin to the Andean Cordillera) covers mainly the Colombia, Ecuador, Perú, Bolivia and Argentina adjoining sectors.
These very large vegetated areas constitute a special case for satellite imagery application in order to take quick knowledge of the whole region which comprises approximately about of 3,000.0|00 km2 in opposition to the arid morpho-climatic systems and so take advantage about natural resources.
Besides, we must take in consideration that the costs and the fast work in perform all classes of cartographies (i.e. today we are making 3D digital cartography based on satellite imageries and ground position systems points spacially located) are now easily realized with satellite imagery.
These results are in this way like largely more effective because of their intrinsic thematic properties, captured for the optical Landsat TM 5 sensor series which are due to sun electromagnetic radiation reflection over the different earth surfaces objects, either natural or anthropogenic.
In order to overcome a future long time sustainable program of general planning in the natural resources and communication lines among south-american countries we began several laboratory and field cartographic actions.
These were in order to carry out a “preliminary” cartography based on satellite digital data, acquired by means of the Landsat 5 thematic mapper sensor and the SAC – C which have on-board the multispectral medium resolution scanner (MMRS) sensors series (175 m spatial resolution).
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