Automatic classification of reforested Pinus SPP and Eucalyptus SPP in Mogi-Guacu, SP, Brazil, using LANDSAT data

The author has identified the following significant results. Single date LANDSAT CCTs were processed, by Image-100 to classify Pinus and Eucalyptus species and their age groups. The study area Mogi-Guagu was located in the humid subtropical climate zone of Sao Paulo. The study was divided into ten preliminary classes and featured selection algorithms were used to calculate Bhattacharyya distance between all possible pairs of these classes in the four available channels. Classes having B-distance values less than 1.30 were grouped in four classes: (1) class PE - P. elliottii, (2) class P0 - Pinus species other than P. elliotii, (3) class EY - Eucalyptus spp. under two years, and (4) class E0 - Eucalyptus spp. more than two years old. The percentages of correct classification ranged from 70.9% to 94.12%. Comparisons of acreage estimated from the Image-100 with ground truth data showed agreement. The Image-100 percent recognition values for the above four classes were 91.62%, 87.80%, 89.89%, and 103.30%, respectively

Estimation of the sugar cane cultivated area from LANDSAT images using the two phase sampling method

A two phase sampling method and the optimal sampling segment dimensions for the estimation of sugar cane cultivated area were developed. This technique employs visual interpretations of LANDSAT images and panchromatic aerial photographs considered as the ground truth. The estimates, as a mean value of 100 simulated samples, represent 99.3% of the true value with a CV of approximately 1%; the relative efficiency of the two phase design was 157% when compared with a one phase aerial photographs sample

Thin-ribbon tapered coupler for dielectric waveguides

A recent discovery shows that a high-dielectric constant, low-loss, solid material can be made into a ribbon-like waveguide structure to yield an attenuation constant of less than 0.02 dB/m for single-mode guidance of millimeter/submillimeter waves. One of the crucial components that must be invented in order to guarantee the low-loss utilization of this dielectric-waveguide guiding system is the excitation coupler. The traditional tapered-to-a-point coupler for a dielectric rod waveguide fails when the dielectric constant of the dielectric waveguide is large. This article presents a new way to design a low-loss coupler for a high- or low-dielectric constant dielectric waveguide for millimeter or submillimeter waves

Caracterização das unidades da paisagem em ambiente de floresta tropical por meio de imagens-fração MESMA.

O objetivo deste trabalho foi discriminar classes de uso e cobertura da terra por meio de imagens-fração derivadas do modelo múltiplo de mistura espectral (multiple endmember spectral mixture analysis - MESMA), considerando as diferentes formações florestais e sistemas agropecuários na FLONA Tapajós e seu entorno, com vistas à caracterização dos principais padrões da paisagem na região

A long-term perspective on deforestation rates in the Brazilian Amazon

Monitoring tropical forest cover is central to biodiversity preservation, terrestrial carbon stocks, essential ecosystem and climate functions, and ultimately, sustainable economic development. The Amazon forest is the Earth’s largest rainforest, and despite intensive studies on current deforestation rates, relatively little is known as to how these compare to historic (pre 1985) deforestation rates. We quantified land cover change between 1975 and 2014 in the so-called Arc of Deforestation of the Brazilian Amazon, covering the southern stretch of the Amazon forest and part of the Cerrado biome. We applied a consistent method that made use of data from Landsat sensors: Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+) and Operational Land Imager (OLI). We acquired suitable images from the US Geological Survey (USGS) for five epochs: 1975, 1990, 2000, 2010, and 2014. We then performed land cover analysis for each epoch using a systematic sample of 156 sites, each one covering 10 km × 10 km, located at the confluence point of integer degree latitudes and longitudes. An object-based classification of the images was performed with five land cover classes: tree cover, tree cover mosaic, other wooded land, other land cover, and water. The automatic classification results were corrected by visual interpretation, and, when available, by comparison with higher resolution imagery. Our results show a decrease of forest cover of 24.2% in the last 40 years in the Brazilian Arc of Deforestation, with an average yearly net forest cover change rate of -0.71% for the 39 years considered

Alterações antropogênicas nos remanescentes de vegetação natural (RVN) de savana do estado de São Paulo no ano de 2009.

Deforestation in São Paulo State was mainly driven by sugarcane and coffee crops during the XVIII and XIX centuries which caused a significant fragmentation in native forests. More recently, between the 1970?s and 1980?s decades the native forest fragmentation process was intensified and also the savannah area was drastically reduced due to sugarcane expansion for ethanol production. Much native vegetation was deteriorated and fragmented into smaller disconnected portions during this period. This work was performed within the scope of a technical cooperative agreement between the Environmental Secretary of São Paulo State (SMA) and the National Institute for Space Research (INPE). It consisted in monitoring monthly the land cover changes of 7,000 polygons of remanescent native vegetation (RVN) in the São Paulo State. The environmental assessment of the vegetation cover status was performed based on mesoregions for better discussion of the geographical distribution of the deforested RVN's from May to December 2009. The results showed that Bauru and Ribeirão Preto mesoregions presented the highest land cover changes with 19.4 and 12.1 km², respectively

Índice de vegetação na detecção de áreas recém-queimadas no Pantanal utilizando imagens CBERS.

Dentre os indicadores de sustentabilidade das fazendas pantaneiras, destaca-se o grau de intensidade de queimadas das paisagens, portanto, há a necessidade de um método prático para quantificar especialmente a intensidade da queima

Utilization of LANDSAT data to inventory the sugar cane in the state of Sao Paulo

There are no author-identified significant results in this report

A novel approach to improve GNSS Precise Point Positioning during strong ionospheric scintillation: theory and demonstration

At equatorial latitudes, ionospheric scintillation is the major limitation in achieving high-accuracy GNSS positioning. This is because scintillation affects the tracking ability of GNSS receivers causing losses of lock and degradation on code pseudorange and carrier phase measurements, thus degrading accuracy. During strong ionospheric scintillation, such effects are more severe and GNSS users cannot rely on the integrity, reliability, and availability required for safety-critical applications. In this paper, we propose a novel approach able to greatly reduce these effects of scintillation on precise point positioning (PPP). Our new approach consists of three steps: 1) a new functional model that corrects the effects of range errors in the observables; 2) a new stochastic model that uses these corrections to generate more accurate positioning; and 3) a new strategy to attenuate the effects of losses of lock and consequent ambiguities re-initializations that are caused by the need to re-initialize the tracking. We demonstrate the effectiveness of our method in an experiment using a 30-day static dataset affected by different levels of scintillation in the Brazilian southeastern region. Even with limitations imposed by data gaps, our results demonstrate improvements of up to 80% in the positioning accuracy. We show that, in the best cases, our method can completely negate the effects of ionospheric scintillation and can recover the original PPP accuracy that would have existed without any scintillation. The significance of this paper lies in the improvement it offers in the integrity, reliability, and availability of GNSS services and applications.</p

Uso de um modelo linear de mistura espectral e índice de vegetação na avaliação de pastagens em degradação no Pantanal.

Este estudo teve por objetivo avaliar áreas de campos degradados por malva-branca por meio de imagens criadas a partir do modelo linear de mistura espectral e índice de vegetação de diferença normalizada utilizando imagens LANDSAT, em período de seca no Pantanal