Caracterização espectral de plantios de Eucalyptus utilizando dados Hyperion EO-1 e SRTMSpectral characterization of Eucalyptus plantation using Hyperion EO-1 and SRTM data

A disponibilidade de dados hiperespectrais trouxe expectativas nos meios acadêmicos e empresariais quanto à potencialidade de sua aplicação no setor florestal. O objetivo deste trabalho foi avaliar a aplicação de dados hiperespectrais do sensor Hyperion EO-1 na caracterização espectral de plantios de Eucalyptus spp. e os efeitos da geometria de iluminação nesse processo. Para avaliar a geometria de iluminação foram utilizados dados topográficos provenientes do SRTM (Shuttle Radar Topography Mission) e as condições de iluminação presentes no momento da aquisição da imagem de satélite, gerando assim um fator de iluminação para a área de estudo. Os dados hiperespectrais foram convertidos para valores de FR de superfície, os quais passaram a constituir os dados fundamentais de todo o trabalho. A área de estudo contemplou os plantios do gênero Eucalyptus spp., pertencentes à empresa Fibria S.A., localizados no município de Capão Bonito (SP). Foram coletados dados de diferentes espécies e em diferentes etapas de desenvolvimento, o que caracteriza diferenças estruturais nos dosséis dos plantios. As componentes principais foram aplicadas nos dados e foram confeccionados gráficos dos fatores referentes às duas primeiras componentes, dos quais foram extraídas informações estruturais sobre os plantios. AbstractThe availability of the hyperspectral data brought expectations in academic and business circles regarding the potential of its application in the forestry sector. The goal of this work was to evaluate the implementation of hyperspectral data of the Hyperion EO-1 sensor in spectral characterization of the Eucalyptus spp. plantations and the effects of illumination geometry in this process. To assess the illumination geometry, topographical data were used from the SRTM (Shuttle Radar Topography Mission) and illumination conditions present at the time of the acquisition of satellite image, thereby a factor of illumination for the study area. Hyperspectral data were converted to values of surface bidirectional reflectance factor BRF, which become the fundamental data of all the work. The study included the plantations of the genus Eucalyptus spp., belonging to the company Fibria S.A., located in the Capão Bonito city, state of São Paulo. Data were collected from different species and in different stages of development, indicating structural differences in the plantations canopy. The principals components have been applied to the data and graphics were made of factors relateding to the first two components were made, and they were extracted provided structural information about the species studied

Phytophysiognomic and land use mapping of partial Alto Taquari basin using TM/Landsat and HRV/SPOT images

TM/Landsat temporal images (dry and wet seasons) and HRV/SPOT images from a dry season, in analogical and digital presentation forms, were used in a physiognomic vegetation and land use mapping in part of Alto Taquari (MS) river basin. The images were available in form of color compositions (TM3B, TM4G and TM5R bands, and HRV1B, HRV2G and HRV3R bands). Visual interpretation was carried out considering the following vegetation and land use classes: Grassland, Savanna (Cerrado), Woodland (Cerradão), Savanna and aluvial forest, Aluvial forest, Disturbed formation, Cultivated pasture, Field crops, and Water bodies. The performance evaluation of TM and HRV products has shown a small superiority of HRV images, compared to TM images. The digital image processing was carried out over the Pedro Gomes topographic chart area, considering only the TM images. Principal component technique was applied in order to generate new images. These two new images were used in the Maxver digital classification procedure. The result of that classification was also transferred to the GIS and compared with visual thematic map through Kappa (KHAT) statistical parameter. The results have shown low similarity between these maps.Imagens TM/Landsat referentes a duas épocas do ano e HRV/SPOT foram utilizadas nos mapeamentos fitofisionômico e de uso da terra de parte da bacia do Alto Taquari (MS). Imagens analógicas foram dispostas sob a forma de composições coloridas (TM3B, TM4R e TM5G; HRV1B, HRV2R e HRV3G). Estas imagens foram interpretadas visualmente, procurando-se identificar os seguintes itens: 1) Campo; 2) Cerrado; 3) Cerradão; 4) Cerrado + mata aluvial; 5) mata aluvial; 6) formação alterada; 7) áreas destinadas à agropecuária; 8) culturas agrícolas implantadas; e 9) espelho d'água. A avaliação dos desempenhos dos dois produtos revelou uma ligeira superioridade dos produtos HRV/SPOT em relação aos produtos TM/Landsat. A área referente a uma das folhas topográficas (Pedro Gomes) foi considerada no processamento das imagens digitais TM/Landsat. Aplicou-se a técnica de componentes principais para a elaboração de duas novas imagens. Seguiu-se a classificação digital pelo algoritmo Maxver (Máxima Verossimilhança), cujo resultado foi introduzido no banco de dados mencionado sob a forma de um Plano de Informação (PI). O PI referente à interpretação visual da folha Pedro Gomes foi então comparado com o PI desta mesma folha, elaborado a partir da classificação digital pela estatística Kappa. Os resultados indicaram pouca similaridade entre os dois PIs

Vegetation index and spectral linear mixing model for monitoring the Pantanal region

This paper presents the contribution of the normalized difference vegetation index (NDVI) and the fraction images derived from linear mixing model for monitoring the dynamic of the land cover in the Pantanal region. The vegetation index and the vegetation, soil, and shade or water fraction images were derived from Landsat TM (Thematic Mapper) digital data acquired over the alto Taquari (MS) region, on December 22, 1992 (dry season) and on March 12, 1993 (rainy season). These images permitted to analyze the land cover in this region for the image dates, as well as to detect changes occurred during the period of image acquisition. The results indicated an apparent higher sensitivity of vegetation fraction image to land cover variation when compared to vegetation index image. The radiometric rectification method presented a good performance, indicating that the selected dark and bright targets in the images have not changed in the interval between dates of image acquisition.Este trabalho apresenta a contribuição da imagem índice de vegetação de diferença normalizada (NDVI) e das imagens-fração derivadas de modelo linear de mistura espectral para o monitoramento da dinâmica da cobertura do solo na região do Pantanal. As imagens índice de vegetação e as imagens-fração (vegetação, solo e sombra ou água) foram derivadas dos dados digitais do TM (Thematic Mapper) do Landsat obtidos sobre a região do alto Taquari (MS), em 22 de dezembro de 1992 (período seco) e 12 de março de 1993 (período chuvoso). Estas imagens permitiram analisar a cobertura de solo da região nas datas das imagens, bem como detectar as mudanças ocorridas entre o período de aquisição dessas imagens. Aparentemente, os resultados indicaram maior sensibilidade da imagem-fração de vegetação às variações de cobertura vegetal do solo quando comparada com a imagem índice de vegetação (NDVI). O método de retificação radiométrica apresentou bom desempenho, indicando que tanto os alvos escuros quanto os alvos claros, selecionados nas imagens, não sofreram mudanças durante o intervalo de aquisição das imagens

IMPACT OF TOPOGRAPHIC CORRECTION ON SOIL AND VEGETATION COVER SPECTRAL CHARACTERIZATION BY TM/LANDSAT 5 IMAGERY

Several topographic correction methods have been developed to be applied to orbital imagery. The main objective of these initiatives has been focused on improving land cover mapping. Despite of some discussions that include spectral approaches, no attention has been given to the impact of such correction on the spectral characterization of different targets. That impact can influence relationships commonly explored between radiometric data from orbital imagery and biophysical and/or geophysical parameters. TM/Landsat 5 images (orbit 218, row 76) from a mountainous region located between São Paulo, Minas Gerais and Rio de Janeiro states (Brazil) were converted to surface reflectance values. Two topographic correction methods considering different sampling strategies were applied. The local illumination was taking into account during the result analysis in order to evaluate the selective effect of the topographic correction on the spectral characterization of bare soils and vegetated surfaces. The results indicated that the sampling strategy influences both the visual aspect of the topographic corrected images and the spectral characterization of targets. Spectral distortions caused by the topographic correction procedures were higher at darker illumination conditions. The topographic correction is a procedure that deserves attention when exploring spectral characterization of different targets. Sometimes it contributes positively in qualitative approaches such as mapping or digital classification, but it can imply in severe influence on quantitative approaches that are dependent on the targets spectral characterization

Dados TM/LANDSAT na identificação do ataque da Vespa-da-Madeira em plantios de Pinus sp

Landsat/TM images (TM3 TM4, TM5 and TM7 spectral bands) from areas covered by Pinus sp. (pinus) stands, sub-tropical forests and grasslands, were selected considering four dates related to the outbreaks of a woodwasp (Sirex noctilio, Fabricius). The selected dates were: 03/27/88, 08/08/90, 06/10/92 and 07/15/93. In 1988 the woodwasp has not been detected in these pinus stands. During the year of 1990, it killed an average 10% of trees. In 1992 and 1993, the outbreaks were reduced to an average of 1% of killed trees, due the application of silvicultural procedures, including timely selective thinning for sustained vigour. All images were matched considering that of 1988 as a reference. Then, they were transformed in reflectance images. Atmospheric correction method was applied in order to reduce the atmospheric influence in the reflectance values. Vegetation index images were made by the ratio between TM4 and TM3 bands images. Multitemporal vegetation indexes were compared with the woodwasp outbreaks and selective thinning data. Meteorologic data were also considered in that comparison. Visual analysis was carried out, using color compositions that have been made by TM3, TM4, TM5 and TM7 bands combinations, trying to identify patterns that could be related to the woodwasp outbreaks. The results showed that the outbreaks and the selective thinning were not detected through both visual analysis and vegetation indexes evaluation.Pages: 557-56

A fisionomia da cobertura vegetal do Parque Nacional do Pantanal Matogrossense (PNPM) identificada através do sensor TM/Landsat: uma análise multitemporal

Pages: 670-67

Reflectância espectral de folhas "ex situ": uma abordagem metodológica

Pages: 15-2