|
|
|
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
The main goals of these preliminary cartographies were focused to serve us for generate a sketch map in which we able to embedded firsts order structural and tectonic lineaments as well as the main drainage systems. So, we can able to construct a master cartographic tool for most civil engineers works as well as for the future planning civil works and sustainable development of the humankind.
These basical and fundamentals actions are certainly valid at the first stages of many engineerical civil projects and human activities, with special importance to prevent hazardous risks and all classes of large landslides movements doing possible to studied and monitored themselves.
These actions and documents are always necessary in order to planning and monitoring different human and natural processes and phenomena with special attention at sustainable region and development.
Materials and Methods
Satellite imagery analyses were carried out to interpreting and sketching-map about of 3,000,000 millions km2 area which are located at the plains and plateaus of South America continent including Brazil, Argentina, Venezuela, Colombia, Guyana, Suriname, French Guyana, Bolivia, Paraguay and Uruguay.
According to Drury (1987) and Sabins (1997), we focused in the employed of optical Landsat TM 5 sensors scenes named as the thematic mapper optical sensor (a special on-board satellite scanner) and some new ones Argentinian’s SAC – C multispectral medium resolution scanner (MMRS) in order to make some comparisons, either spatial, temporal, seasonal, multispectral and radiometric resolutions.
The SAC – C orbits employed were 222/000, 223/000, 224/000, 225/000, 226/000, 227/000, 228/000, 229/000, 230/000 and 231/000 all acquired on fall and autumn season on 2000 and 2001.
The multispectral medium resolution scanner has a “standard” spatial resolution of 175 meters and its spectral resolution bands include channel 1, 2, 3, 4, 5 being 1, 2, 3 visual spectra and 4-5 near infra-red spectra, somewhat similar to the Landsat sensor.
After digital image composition was generated and histogram matching and directional and non-directional filtering was performed, then we made a mosaick with a 4/5/3 enhanced composition. Classical digital image processing software were employed to handle the raw archives of the SAC - C satellite as well as many Landsat TM 5 scenes.
Many images observed in the Glo Vis® project (USGS) were studied to complement our analyses of the structural and drainage continent. The images of the Glo Vis servers are resized to 240 and 1000 meters. However, four this class of studies they were fully applicable and very useful. For each orbit-point they are a complete set of composed scenes from different dates which serve us for several critical comparisons.
The created sketch-map mosaick was not geo-referenced because the objective of the work.Previously, we made the histogram matching and the feathered processes. We used the five/seven bands that carry the Landsat/SAC – C satellites in order to make several masters datasets in two combinations: 3/4/5 and 4/5/3.
So, we create the false-colored images, the unsupervised and supervised classifications and then, we also used it for other transformations as the called as Principal Components Analysis (PCA). Some of these actions were useful for later geomorphological and health-forest interpretations.
It necessary to mention that field recognition was made out in several selected field-points to check out interpretations, with special attention to the railroad crossing places.
We finally used this temathic-planimetric preliminary cartography for structural and drainage visual analysis and interpretation as well as to outline lowland areas (recurrent floodable sectors) and many active geomorphic elements (i.e. large distal alluvial fans present at the foothill of the Andean foreland areas.
Herein, it is include the drainage network system which is basic for any planning of medium-to-large projects as well as a fundamental quantification of the forest and vegetated scarce wrapper area.
|
|
|