National Institute for Space Research
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Quantificação de atributos físico-químicos do solo através de dados espectrais (Vis-NIR-SWIR) obtidos em laboratório e por imagem aérea hiperespectral
No full textThe fertility assessment is essential to assure appropriate soil management and to perform a competitive and sustainable agricultural production. The soil sampling and analysis are the traditional instruments to determine physical, chemical and mineralogical soil attributes. However, to get information enough to mapping the soil variability its necessary high amounts of laboratorial analysis, which bring high costs, its time demanding and produces potentially polluting waste. The correlation of the soil attributes and the electromagnetic energy reflected by the soil can be an option to depict the soil attributes in a rapid and not destructive way. In the last years several authors have obtained promising results in the prediction of soil physical-chemical variability through the soil spectral behavior in the visible, proximal infrared and short wave infrared (Vis-NIR-SWIR, 350-2500nm) coupled with mathematical methods like Partial Least Squares Regression (PLSR). In this sense it was evaluated the use of different spectral information sources on the quantification of soil attributes. For that, the sensor FieldSpec Pro (ASD Inc., USA) at the laboratory level and images obtained by the hyperespectral airborne sensor ProSpecTIR V-S (SpecTIR LLC, USA) were employed, both devices collecting data on the Vis-NIR-SWIR. Better results were obtained with the laboratory sensor, but some satisfactory predictions were obtained with the airborne data proven the potential of this information source in the assessment of soil properties.Pages: 530-53
Análise espectral de Brachiaria brizantha cultivada em solo contaminado por diferentes volumes de hidrocarbonetos líquidos
No full textThis paper describes a method to identify small leakages across the underground hydrocarbon pipelines through the monitoring of the cultures that are at the surface since the leakage from the pipe will cause soil contamination causing loose of leaf and minimal grow from the roots. Such impact can be noticed by the remote sensing products once there will be changes in the spectral reflectance patterns of vegetation by comparing with healthy vegetation. The objective of this study is to benchmark different volumes of contaminants (diesel and gasoline) applied on the soil to then identify the volume that shall affect the development from the observed specie (Brachiaria brizantha) but without avoiding the germination of the seed and the leaf growth, which would impact the spectral data acquisition from the vegetation. Twenty one (21) recipients were built and store in a greenhouse then applied 140, 270, 500 or 530 ml of gasoline or diesel at the soil, afterward seeds of the Brachiaria brizantha were planted. After 45 days, new spectral measurements were taken in the leafs and canopy at each recipient. The acquired spectral curves allowed the identification from the health and non-health vegetation. The first derivative of the reflectance spectral highlighted the differences between the curve of the data samples (health and non-health). The conclusion of this study enabled the volume of contamination set that will be used into the next study with additional data samples that will allow a more representative analysis.Pages: 1533-153
Sensoriamento remoto no estudo de solos
No full textAs geotechnologies presently advance, remote sensing has been considered an important tool to monitor and evaluate natural resources, especially soil (Demattê and Garcia, 1999; Terra, 2011). The study of soils by remote sensing is based on the fact that the interaction between its physical, chemical and mineralogical with electromagnetic radiation occurs in specific lengths, so it is possible to identify and characterize them (Andronikov and Dobrovolskiy, 1991). This study aims to characterize the overall spectral behavior of a soil profile, through spectroradiometry in laboratory. The morphological characterization of the spectral curves of soils was performed by the means of qualitative evaluations based on methods employed by Demattê (2002), Bellinaso (2009), Demattê and Terra (2010) and Terra (2011). It is possible to verify the influence of constituents: iron, organic matter, particle size, moisture and mineralogy across the wavelength. It was observed that the sandiest horizons showed high reflectance of around 85%. The organic matter attenuated reflectance in the surface horizons, masking the effect of soil gradation to the length of 1850 nm. The qualitative evaluation method applied in this study allowed the characterization of the soil. The reflectance spectroradiometry proved to be a remote sensing technique highly effective in spectral characterization of soil.Pages: 9012-901
Estudio de acuíferos kársticos tropicales aplicando tecnologias de teledetección y sensores remotos
No full textThe study area corresponds to the karst aquifer of the Sierra de San Luis and is located in the central region of the state of Falcón (Venezuela) The more specific aspect of a karst aquifer heterogeneity is organized: the gaps, and the flow itself, to be nesting, the effect of the evolutionary process of karstification, from the surface to the upwelling. While the remote sensors are not able to provide direct information groundwater in most cases the morphology, hydrology and geology conditions governing groundwater can be studied and identified in a product obtained from a remote sensor. This paper describes the methodology followed for the main features of a karstic relief such as sinks and springs and inference hydrogeochemical processes affecting it. The best results refer to the supervised classification of LANDSAT7 ETM +, the multitemporal analysis, representation of variable height from uma DEM image ASTGTM and partnership, the surface temperature from the thermal band of Landsat behavior decarbonation process.Pages: 5079-508
Estimativa da Fração de Cobertura Vegetal para o ano de 2010 em Minas Gerais a partir do NDVI gerado pelos sensores MODIS e VEGETATION-2
No full textThe satellite remote sensing offers different means for acquiring the variability of vegetation cover dynamics important for many applications, such as agriculture, forest, meteorology, cartography and urban cadastre. A large amount of images produced by satellites, often available for free, facilitate remote sensing studies. Many of these studies use the Vegetation Indices (VIs) that are derived using the reflectance properties of vegetation. Different indices have different advantages in retrieving vegetation information. The Normalized Difference Vegetation Index (NDVI) allows not only map the vegetation, but also measure the quantity and condition of vegetation in a given area. In this research fraction vegetation cover (FVC) was estimated using the NDVI from MODIS/TERRA and VEGETATION-2/SPOT sensors. The MOD13Q1 NDVI product from MODIS and S-10 NDVI product from VEGETATION-2 were used by the state of Minas Gerais in 2010. The Integrated Land and Water Information System (ILWIS) software was used to support, import, process and analyze the special information. The results showed that the values of NDVI were higher from MODIS sensor. During the rainy season, from September to April, both sensors generated high NDVI values. The FVC values from MODIS were lower than the values of FCV from VEGETATION-2 for the entire period of study.Pages: 3275-328
Taxas de uso em uma série histórica de pivôs centrais em uma bacia do Cerrado
No full textWater consumption is a key element in water resources plans. The one sector that most consumes water is agriculture, which drags around 72 % percent of all water used in Brazil. The technification of agriculture and the increasing demands for higher yields has put irrigation at the front edge of water consumption growth. This scenario requires that the irrigating activity be better known as to let good prognosis be done, producing more trustable figures. This paper proposes a methodology to qualify the use of central pivot irrigation equipment installed in a catchment in central Brazil, the São Marcos catchment. Based on the NDVI, calculated on Landsat imagery, it was determined the rate of effective use of irrigating structures. It is possible to see that the effective use of water is around 55% of all the area destined to irrigation under central pivots during the dry season in the area studied. This method opens doors to new possibilities in water management and water balance in planning scenaries.Pages: 320-33
Variabilidade espaço temporal do albedo da superfície no semiárido pernambucano com base em imagens do TM/Landsat 5
No full textIn this study we used remote sensing techniques to estimate and evaluate the spatial and temporal variability of surface albedo in semiarid Pernambuco. Four images of the sensor Thematic Mapper (TM), Landsat 5, dated 12/12/1991, 09/12/1996, 13/12/2003 and 27/11/2009, constituted the experimental unit, which were estimated using the algorithm Surface Energy Balance Algorithms for Land (SEBAL). In general, it can be seen that where there are natural vegetation albedo was always lower in relation to the modified areas, which are systematically with higher values on all investigated days. It is concluded that remote sensing techniques proved efficient to quantify the spatio-temporal variability of surface albedo for the semiarid conditions of Pernambuco.Pages: 7468-747
Estimativa de totais de domicílios por pixel com o uso de sensoriamento remoto: uma aplicação do modelo People in Pixel
No full textThe spatialization of data socioeconomic considering the unit of the spatialization in matrix based in the pixel allows greater freedom in defining the spatial slices, enabling the quantification of variables linked to the spatial resolution of the pixel. Thus, there is the need to estimate and to spatialize the socioeconomic variables to understanding about spatial patterns, and with this get support to the urban planning actions in big cities. The aim of this study is to quantify the number of households per pixel, using the sensor Landsat TM5, in the city in Rio de Janeiro, and mapping the distribution of this variable by watersheds and along the avenue Brazil. For development this research was used a methodology developed in Brazil and known as "people in pixel", initiated by Nogueira (2005) enhanced by the Cruz et. al (2007), with innovation in this research, focused on quantification of households. The methodology presented good results allowing to conclude that in the area of direct influence of Avenue Brazil, with about 2km, there are an estimate of 25,861 households, and in the distribution of households by basins, the highlight is the Sepetiba basin with 340.420 households. This research can contribute to the dissemination of the model "People and pixel", in the quantification and estimation of households, with support of satellite images, in the various researches on socioeconomic data. The model can support the count of households conducted by the IBGE, presenting estimates and projections and yet support for the years between the Census in Brazil, among other applications.Pages: 1167-117
Detecção e estimação da velocidade de alvos móveis em imagens SAR multivisada
No full textThis work presents a methodology for ground moving target detection and velocity estimation with a single channel SAR. A multilook processor generates two coregistered complex SAR images that are used in a DPCA (Displaced Phase Center Array) processor to detect moving targets and reject the stationary clutter. Given the moving targets position, the targets slant range velocity is estimated by the Doppler shift in the azimuth spectrum of the target. The target azimuth velocity is estimated by the distance between the two different positions that the target, with azimuth velocity, appear in the DPCA output image. Using simulated raw data and the Range-Doppler algorithm, the processor performance is evaluated with good results in presence of the noise and stationary clutter.Pages: 8351-835
Uso de geotecnologias gratuitas na avaliação de imoveis decretados para desapropriação por interesse social no INCRA do Rio de Janeiro: O caso do quilombo de Santana
No full textSince the Federal Decree 4887-2003 was publish, it has been attributed to National Institute of Settling and Agrarian Reform (INCRA) the execution ofprocedures for recognizing, establishing limits and regularization ofethnic territories identified as quilombolas. Many technical analysis are necessary to regularize these territories, including the obtaining of rural properties inserted into a predetermined perimeter for expropriation by social interest. The process of obtaining properties includes legal guidelines established in own normative instrument witch provides the study of criteria for land use and occupation as well as the verification of compliance with environmental law by the property owner at the time of evaluation, under penalty of discounts on the values offered for the Brazilian State in indemnity action as compensation for recovery of permanent preservation areas and deployment of legal reserve. In this article we present the application of free softwares SPRING and QuantunGis in the spatial analysis of land use and occupation and also the verification of compliance with environmental law by rural property in expropriation process. Thus, we will describe the working structure performed on INCRA of Rio de Janeiro (INCRA SR07) by technical team responsible for the preparation of a property appraisal report (LAF) which supports expropriation process aiming to provide the land titles of Santana's quilombo, located in the city of Quatis, state of Rio de Janeiro, Brazil.Pages: 5259-526