National Institute for Space Research
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Uso do Geoprocessamento na determinação das perdas de solo por erosão laminar na Bacia Hidrográfica do Córrego Canabrava
No full textSoil erosion is a natural occurring process and is one form of soil degradation, but, nowadays is one of the most critical environmental hazards of modern times. Soil erosion creates serious problems in agriculture and water resources because removes the top fertile soil and its subsequent deposition in reservoirs and lakes. Therefore, is necessary quantifying this kind of erosion by predictive erosion models. For this purpose, Universal Soil Loss Equation (USLE) is commonly used for erosion model. This equation uses parameters that are mandatory inputs to USLE, such as, rainfall erosivity factor (R), soil erodibility factor (K), slope length and steepness factor (LS), crop management factor (C) and conservation practice factor (P). USLE is useful tool for evaluating soil erosion and establishing soil erosion management plans. The objective of this research was apply Shuttle Radar Topographic Mission (SRTM) data for erosion modeling through USLE equation, to map erosion prone areas in Watershed of Canabrava River, in Guaraciama County, using Geoprocessing. The area of study is approximately 4547.94 ha. The results identify erosion susceptibility zones based on USLE parameters, and, about 30% of area of research was classified as severe erosion. The Geoprocessing is an essential tool in soil erosion studies and consequently in the development of appropriate soil conservation strategies.Pages: 4002-400
Fortran and C codes for higher order and degree geopotential and derivatives computation
No full textGeopotential computation in general did not present numerical problems in older models where order and degree were as low as 30. However with the appearance of much higher order and degree the older conventional algorithms could not be used anymore. The kernel of such algorithms is the recursive computation of the Legendre polynomials. They must be computed in their normalized recursions and variants to avoid numerical flaws at a cost of more expensive processing times mainly due to the need of square roots computations. This paper outlines the main implementation aspects of the geopotential computation and derivatives to higher order and degree. The codes were tested up to 2159 order and 2190 degree without any noticeable flaw. It is expected some numerical degradation near the poles, however to the 0.000001° of proximity, i.e. \ub189.999999° latitude, no problems are reported. Computer codes were developed in double precision and are freely available in Fortran-77 and ANSI-C languages.Pages: 2201-221
Mapeamento e Zoneamento Agroclimatológico do parque cafeeiro de Iúna, ES
No full textEsse estudo objetivou-se dimensionar a área ocupada com a cultura do café no município de Iúna, ES e realizar o zoneamento agroclimatológico para as culturas do café conilon (Coffea canephora Pierre ex Froehner) e café arábica (Coffea arabica L). A fotointerpretação foi feitas nas aerofotos obtidas pelo levantamento aerofotogramétrico do estado do Espírito Santo, referente a julho de 2007. Os resultados revelam que o município de Iúna, ES, possui 25,90% de seu território ocupado pela cafeicultura, o que representa 119,16 km². O zoneamento foi elaborado no mesmo programa, por meio da combinação dos mapas da temperatura média anual do ar e da deficiência hídrica anual, favoráveis ao desenvolvimento da cultura. Detectou-se que 100% da área do município é apta para a implantação do café arábica. Para o café conilon (99,30%) é restrita para temperatura e apta par Déficit Hídrico. Em geral da área do município, só á restrições apenas para o café conilon (0,70%) inapta para Temperatura < 20\ub0C e apta Déficit Hídrico.Pages: 289-29
Aplicação de geotecnologias na caracterização da qualidade da água de um trecho do Rio Extrema, no município de Anápolis - Goiás
No full textThis study aimed to characterize the water quality of the Extreme River in Annapolis City using geotechnologies support. The characterization was to evaluate the quality of raw water, stretches through the sample quality indicators physico-chemical and bacteriological parameters. The sampling was conducted upstream and downstream of potential sources of pollution that these locations were georeferenced and the results were analyzed by means of the CONAMA 357/2005 Legislation which provides for the water classification and guidelines for your ambient and also establishes the conditions and effluent discharge standards. Along with Extrema River waters analysis was also performed to calculate the IQA (WQI -Water Quality Index), which served a support for this diagnosis, thus were spatialized in risk maps of the points location that were collected water samples along the studied stretch. For this were used GPS receivers to the demarcation point in place and the use of GIS (Geographic Information System) software for creating this mapping, these tools serve as support to conduct this study efficiently enabling the generation of subsidies for environmental monitoring agencies in making decisions and monitoring of potentially polluting activities in the region, mainly because it is a river that serves as water source for supply of coastal communities.Pages: 5315-532
Caracterização morfométrica e delimitação da bacia hidrográfica do Córrego Samambaia-GO a partir de dados do SRTM
No full textThe present article has as objective show boundary and morphological characterization of the watershed of córrego Samambaia, located in Goiânia City- TO, state of Goiás. Therefore, a Digital Elevation Model (DEM) from the SRTM (Shuttle Radar Topography Mission) mission was processed using the ArcGIS SIG-software for the extracting of principal morphometric parameters and boundary. The contribution area was found to be 32,67 km², with a perimeter of 29,78 km. The watershed has an elongated form, a coefficient of compacity of 1,45 an index of circularity of 0,46, not favoring flood, and drainage density of 0,695 km/km², average slope of the watershed of 2,93% while your main stream, córrego Samambaia, has a value of 1,14%, the average elevation of the watershed is 775 m, the concentration time obtained by two methods, Tsuchiya methods and direct methods, obtaining values equal to 75,41 and 76,32 minutes, respectively. DEM processing has shown to be highly efficient for watershed parameterization watershed study.Pages: 5880-588
Efeito do sombreamento do relevo em relação à latitude nas imagens Landsat TM e ETM +: qual a melhor época do ano para aquisição no Hemisfério Sul?
No full textWhen images acquisition choose up scenes with low cloud cover to prevent targets loss spectral information. But shaded areas appears especially in training samples collecting for supervised classification. This fact is similar to the clouds reported because "shadow" spectral information is the same in all bands. This problem in mountainous areas can be steep and conducive to greater coverage of this class due to higher projected shadows. To resolve this issue the same conditions of relief was simulated under the shading variation due to latitude increase. To this, were processed direct solar radiation models for the days and pass times Landsat TM and ETM+ in the Southern Hemisphere. Thus, it was found that 30°S and 40°S latitude the area shading goes loss from 27% to 91% one should images acquire between October and February. At 0° and 10°S latitudes loss can be negligible if a minimum threshold of occurrence be fix by 10%. In terms of exposure radiation for solar surfaces, it was found that south and west surfaces received less illumination throughout the year and in the higher latitude, it problem can be considered if the images are acquired during the equinoxes in noonday sun time.Pages: 4899-490
Cálculo de la fracción de agua subpixel en datos MODIS para el monitoreo de inundaciones en la provincia de Buenos Aires
No full textThe aim of this work is to develop an easy methodology to evaluate, quantify and monitoring the flooded areas within Buenos Aires province. This study investigates how to derive water fraction and flood mapping from the Moderate-Resolution Imaging Spectroradiometer (MODIS) onboard the Earth Observing System (EOS) satellites using the linear mixture model. Satellite- derived flood maps in near-real time are vital to stake holders and policy makers for disaster monitoring and relief efforts. Precise mapping of floods and standing water is also required for detecting deficiencies in existing flood control and for damage claims. MODIS Band 5 and the difference Band2-Band1 were used to find the threshold values to determine pure water pixel, pure land pixel and those mixed pixels, where the water proportion is calculated. Finally, using administrative vector the flooded area was calculated and using weekly products is possible to monitoring the evolution. The preliminary results by visual evaluation with Landsat data acquired on same date show that the simple methodology can be employed for mapping water, although adjustment of the threshold based on actual situations is necessary.Pages: 1322-132
Detecção da necessidade de suplementação nitrogenada para o algodoeiro usando imagens do sensor AWiFS e espectrorradiometria
No full textRapid and non-destructive estimation of crop nitrogen content is a potentially important application for farmers optimize the management of nitrogen fertilization. The objective of this work was to study the behavior of three vegetation indices obtained by both AWiFS satellite images as by field spectroradiometry data and evaluate their sensitivity to distinguish the leaf N content during the 2011 cotton season, in commercial field of Goiás state. Hyperspectral reflectance was measured at 0.5 m above the cotton canopy on February 08 and April 01, 2011 using an PAR-NIR Apogee\uae spectroradiometer. Corresponding leaf area index, SPAD-502 readings and plant height were also measured on these dates. Hyperspectral data were carried out to compare performances of existing vegetation indices: Normalized Difference Vegetation Index (NDVI), Modified Soil-Adjusted Vegetation Index (MSAVI) and Tranformed Vegetation Index (TVI).Results show that hyperspectral reflectance data using vegetation indices reached significant levels of accuracy in the retrieval of N levels for both evaluation dates, where the NDVI and TVI showed the best performance. The low resolution of the images sensor AWiFS not allow identification of the spatial variability of nitrogen content in cotton plants at first flowering on February, 08. At the stage of maximum flowering, both hyperspectral vegetation indices as obtained by satellite images of medium resolution presented themselves as good estimators of leaf nitrogen. The NDVI and TVI obtained by spectroradiometry can be used as an economical and quick alternative to recommend supplementation of nitrogen fertilization on cotton planting in the Brazilian cerrado.Pages: 778-78
Avaliação temporal da vegetação, albedo de superfície e temperatura de superfície no Distrito Federal, por meio de imagens orbitais de média resolução
No full textThe purpose of this study is analyse the Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI), Leaf Area Index (LAI), surface albedo and surface temperature for the city Brasilia, Federal Distrito. The analysis was performed using Landsat satellite imagery - 5 provided by the National Institute for Space Research for the years 1985, 1994 and 2005. The results describe an increase in surface temperature due to process artificialization soil and variations in the albedo was clear the change in albedo of different periods, and the annual variation of albedo is a source of many factors, including variation in composition of the soil cover. The city of Brasília presents quite peculiar characteristics that come from being a planned city including as regards its location, and that over the years has been modified with the new trends of ownership and occupancy of their territorial space, Gomes (2011 ). The objective of this work is to obtain temporal assessment, the period between the years 1985 to 2005, vegetation cover, surface albedo and surface temperature in Brasilia no Distrito Federal, based on the quantification of the level of standards morphological that depend on geographic location and climatic conditions of the area imaged.Pages: 8277-828
Mineração de dados e análise de imagens baseada em objeto aplicadas ao mapeamento de cobertura da terra
No full textThis article is committed to evaluate the performance of a semantic network generated by data mining for the classification of land cover using GEographic Object-Based Image Analysis (GEOBIA) in a tropical mountainous area. The study area corresponds to the Nova Friburgo County, with an extension of 933 km², located in the region of the Fluminense Ridge, presenting thus a steep mountainous relief. Based on a visual interpretation of the images, eight land cover classes were defined: rockies, forest, grasslands, sparse grasslands, burn scars, reforestation, shadow, and urban areas. The dataset used for data mining was composed by 130 attributes and by 225 training samples accounting for all land cover classes. The algorithm C4.5, implemented in the software Weka 3.6.4, was employed for the data mining procedure. The following attributes were selected by C4.5: NDVI, fourth principal component, second angular moment, homogeneity, entropy, and slope. The obtained global accuracy was 88%, and the Kappa index reached 0.81. Only the class urban areas presented omission errors greater than 50%, being confused in some cases with sparse grasslands, forest, and burn scars. In view of the obtained value for the Kappa index, we can state that the classification presented an excellent accuracy according to a rating scale specially elaborated for such index.Pages: 2282-228