53 research outputs found

    Polarimetric Responses and Scattering Mechanisms of Tropical Forests in the Brazilian Amazon

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    This chapter discusses the polarimetric responses of PALSAR (L-band) data and scattering mechanisms of some tropical forest typologies based on target decomposition. The fundamentals of polarimetric theory related to both SAR topics under development are summarized. For representation of polarimetric signatures, the cross-section of the forest target (σ) was plotted on a bi-dimensional graphic as a function of the orientation angle, ellipticity angle and the intensity of co-polar components of the radar signal. The analysis of scattering mechanisms was done by the association of entropy and mean alpha angle values of each sample, plotted in a bi-dimensional classification space. This study improves the understanding of the interaction mechanisms between L-band PALSAR signals and structural parameters, supporting the forest inventory in the Brazilian Amazon region

    Efetividade de uma iniciativa de manejo para contenção da exploração florestal ilegal em um Projeto de Desenvolvimento Sustentável em Anapu, Pará.

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    A pressão por áreas florestais a serem exploradas é constante na Amazônia. Projetos de Desenvolvimento Sustentável (PDS) constituem uma modalidade de assentamento rural com objetivos sociais e ambientais, tendo o manejo florestal sustentável como alternativa para geração de renda. Utilizando a metodologia de ?Detecção de exploração madeireira em tempo quase real? (DETEX), desenvolvida pelo Instituto Nacional de Pesquisas Espaciais (INPE), este estudo analisou a ocorrência de exploração florestal licenciada e não autorizada no PDS Virola-Jatobá (PDS-VJ), município de Anapu, Pará, no período de 1999 a 2016. Foram identificadas alterações não autorizadas em 18.519 ha, sendo que 92% desta alteração ocorreram anteriormente a 2004, quando houve o assentamento das famílias, e outros 4,9% ocorreram quando o plano de manejo conduzido pela associação local não havia iniciado ou estava interrompido. Os resultados comprovam a assertividade das técnicas utilizadas, embora limitadas pela resolução espacial das imagens Landsat. O PDS-VJ, apesar de ainda não ter sido eficaz na consolidação de meios de vida sustentáveis, tem no manejo florestal uma alternativa que se mostrou promissora na contenção da exploração florestal não autorizada, pois apenas 3,1% das alterações ilegais observadas ao longo de 18 anos ocorreram durante sua vigência

    Land-use and land-cover mapping of the Brazilian cerrado based mainly on Landsat-8 satellite images.

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    The Brazilian Cerrado is one of the world´s biodiversity hotspot and hosts some of the most intensive agricultural activities for food production in the world. The objective of this study was to produce a land-use and land-cover (LULC) map of the Cerrado based on Landsat-8 Operational Land Imager (OLI) images. A set of 121 scenes from 2013 was processed using the image segmentation technique. The segments were exported in the shapefile format and interpreted visually in a geographical information system software using RGB/564 color composites. The following LULC classes were considered: annual croplands, perennial croplands, cultivated pasturelands, reforestation, mosaic of occupation, urban areas, mining areas, bare soil, forestlands, non-forestlands, water bodies, and non-identified (clouds and burned areas). The overall accuracy was estimated by an independent scientist with large experience in Cerrado´s image interpretation. The results showed that 43.4% of the study area (88.5 million hectares) were already converted into agricultural, urban and mining areas, 54.6% (111 million hectares) were still natural areas, and 1.9% (3.9 million hectares) was classified as non-identified. Cultivated pasturelands were the most representative land-use type (29.5%), followed by annual croplands (8.5%) and perennial croplands (3.1%). The overall accuracy of the final map was 80.2%.Título em português: Mapeamento de uso e cobertura de terras do cerrado com base principalmente em imagens do satélite Landsat-8

    Land-use and land-cover mapping of the Brazilian cerrado based mainly on Landsat-8 satellite images.

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    The Brazilian Cerrado is one of the world´s biodiversity hotspot and hosts some of the most intensive agricultural activities for food production in the world. The objective of this study was to produce a land-use and land-cover (LULC) map of the Cerrado based on Landsat-8 Operational Land Imager (OLI) images. A set of 121 scenes from 2013 was processed using the image segmentation technique. The segments were exported in the shapefile format and interpreted visually in a geographical information system software using RGB/564 color composites. The following LULC classes were considered: annual croplands, perennial croplands, cultivated pasturelands, reforestation, mosaic of occupation, urban areas, mining areas, bare soil, forestlands, non-forestlands, water bodies, and non-identified (clouds and burned areas). The overall accuracy was estimated by an independent scientist with large experience in Cerrado´s image interpretation. The results showed that 43.4% of the study area (88.5 million hectares) were already converted into agricultural, urban and mining areas, 54.6% (111 million hectares) were still natural areas, and 1.9% (3.9 million hectares) was classified as non-identified. Cultivated pasturelands were the most representative land-use type (29.5%), followed by annual croplands (8.5%) and perennial croplands (3.1%). The overall accuracy of the final map was 80.2%.Título em português: Mapeamento de uso e cobertura de terras do cerrado com base principalmente em imagens do satélite Landsat-8

    Dinâmica das áreas de reflorestamento no município de Paragominas, Estado do Pará, considerando dados temporais do projeto TerraClass.

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    The municipality of Paragominas is considered a model among the municipalities of the "Legal Amazon", being the inspiration for the program "Municipios verdes", because it was through him and other public policies that the municipality managed to leave the list of municipalities that more Deforested and has been showing an expansion of reforestation practice. This study aims to analyze the dynamics of land use and occupation in the municipality of Paragominas, from 2008 to 2014, with emphasis on reforested areas in the municipality, using maps with land use and land cover data derived from remote sensing and Geoprocessing. The results indicated that although Paragominas faced an apparent consolidated situation in relation to the dynamics of land use, it continues to suffer a huge loss of forest resources. However, this municipality also showed a high conversion of pasture fields to agriculture, forest plantations or regrowth areas. Despite being a region apparently consolidated in terms of space exploration, Paragominas continues to suffer a great loss of forest resources, which can be seen in the gradual increase of the areas of use, the changes in the areas destined to reforestation projects came from the increase of the planted areas And the diversity of plant species

    A confiabilidade do PRODES: estimativa da acurácia do mapeamento do desmatamento no estado Mato Grosso.

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    PRODES is completing almost thirty years of uninterrupted monitoring of clear-cut deforestation over the Brazilian Amazon. Until now, no estimate of its mapping accuracy has been made. In this sense, this article brings a first approximation of mapping accuracy estimation of PRODES deforested areas, taking as example the state of Mato Grosso for the year 2014. For this, a random sampling panel was constructed, stratified with two strata, the deforestation of 2014 and the remaining forest. The sample size was calculated using the binomial function. In addition, a web platform was built to evaluate the points drawn by three independent evaluators. The global accuracy of the mapping of deforestation for the state of Mato Grosso, for the year 2014 was 94.5%, and may vary between 92.4% and 96.5%, in the evaluated scenario there was no class discordance to be found. Regarding the Forest class, the user accuracy was 90.5% and the producer's accuracy was 88.4%, this imbalance between user accuracy and producer accuracy indicates that there is a tendency for the forest class area to be underestimated for this mapping, in this year

    Land use dynamics in the Brazilian Cerrado in the period from 2002 to 2013.

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    The objective of this work was to analyze land use dynamics in the Brazilian Cerrado region from 2002 to 2013. This analysis was based on the interpretation of Landsat satellite images carried out by the projects Projeto de Conservação e Utilização Sustentável da Diversidade Biológica Brasileira (Probio) and TerraClass Cerrado 2013, both coordinated by Ministério do Meio Ambiente. In 2002, 38.9% of the Cerrado was covered by some type of anthropic activity. In 2013, this percentage increased to 43.4%. One of the main highlights is the emergence of a new agricultural frontier in the northern region of the study area, known as Matopiba.Título em português: Dinâmica do uso das terras no Cerrado no período de 2002 a 2013
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