National Institute for Space Research
Biblioteca Digital da Memória Científica do INPENot a member yet
6175 research outputs found
Sort by
Variação anual do EVI e NDVI de tipologias vegetais na APA de Ibirapuitã, Rio Grande do Sul, Brasil
No full textThis aimed to study the phenology of different vegetation typologies that cover the Ibirapuitã environmental protection area (APA), located within the Pampa biome, Rio Grande do Sul. The objective was to verify the existence of seasonal patterns to allow discrimination of vegetation types through analysis of MODIS/vegetation indices time series. Also, we investigated the differences in the responses of the two vegetation indices - EVI and NDVI - of the main vegetation typologies of the APA for 2011. EVI and NDVI annual and intra-annual averaged data were collected and analyzed in the form of graphs and z statistics. The results showed that, during the summer and spring, there is a higher spatial heterogeneity and a greater productivity of the studied typologies, while in winter and autumn, during the period of senescence, there is less biological activity and increased spatial homogeneity of the spectral responses of plant types (with the exception cultivated pasture which is planted in autumn and winter). Among the herbaceous typologies, prostrate and cespitous grasslands, cultivated pasture and invasive-annoni showed varied mean values of EVI and NDVI, however, with similar seasonal trends. Despite the intra-annual differences found, typical patterns, which would allow the discrimination of vegetation types through temporal series analysis, were not observed here. NDVI values showed greater sensitivity to intra-annual phenological variations of the vegetation types considered.Pages: 2778-278
Ferramenta QLMODIS para rápida visualização e seleção de produtos MODLAND
No full textThe importance of MODIS (Moderate Resolution Image Spectroradiometer) products have been presented by several works available in the literature. These works presented and discussed the high quality of the products derived from MODIS sensors such as: high geometric quality of its images, 36 spectral bands, coverage of terrestrial globe each 2 days, i.e., high temporal resolution and free downloaded, what has caused a significant increase on temporal rate of data volume for several applications and researches. These products are provided free of charge by NASA (National Aeronautics and Space Administration) in a systematic way, allowing to use them for several studies. However, the multiplicity of data types, data specifications and the different functions they were developed to feature require a clear understanding by potential users of the whole set in a systematic schedule. In this context, the main objective is to present the QLMODIS tool, an interface for data distribution developed to facilitate the users to choose the best image dates, or periods, to obtain MODLAND data, designed for the studies of terrestrial ecosystems, in a simple and rapid way, so speeding up the selection of the data layers properly designed for each application. The proposed tool will facilitate to select images for the users who already have defined their research objectives, as well as a support in the planning stage of hardwork main processing of environmental information. Therefore,the present description of QLMODIS tool will be very useful for several (and potential) users of MODLAND products.Pages: 8162-816
Padrões da evapotranspiração e índice de NDVI nos diferentes usos de cobertura do solo em três sub bacias do rio Paracatu/MG
No full textThe accurate mapping of the land use and land cover (LULC) and its influence on hydrological cycle form the basis for future conservation and catchments management. The goal of this paper is to analyze the impact of land use and land cover on evapotranspiration, land surface temperature (LST) and NDVI of the tree sub basins in Paracatu catchment. The results demonstrate that the high values of NDVI were found on riparian vegetation, irrigates cultures an eucalyptus plantations and the lowest values were restricted to pastures. The LST has the same behavior, that is, that the temperatures between 170C a 200C were registered on riparian vegetation, irrigates cultures an eucalyptus plantations, and the highest on pastures areas. The highest values on evapotranspiration (ET) (mm/day) were registered on water bodies (rivers and lakes) and irrigated areas with values of (8.18 a 10 mm/day) and eucalyptus plantations registered values between (9.38 a 10mm/day). The pastures and areas with poor vegetation has ET values of (6.3mm/day). The parameters LULC, NDVI, LST and ET are interconnected, i.e., the different LULC will constrain the vegetation of a certain area, which will have a particular value of NDVI, LST and ET. Accurate information of these parameters will have a crucial importance as they can contribute to the understanding its influence in physical parameters on catchments dynamics.Pages: 7492-749
Variações de MDTs gerados a partir de dados LiDAR: Estudo comparativo entre diferentes classificadores
No full textAutomatic cloud point classification of airborne LiDAR (Light Detection and Ranging) data into ground and non-ground points is an important step for both ecological and forest management analysis. We evaluated three freeware filtering algorithms for ground classification. Our study area is located in western Washington State (USA). The area contains different land use classes ranging from bare soil to shrubland, log forest and dense forest. We compare the different ground classification results each other and faced it with a topographic map. The high point density of the LiDAR dataset (>4 points·m2) brought us good classification results based on RSME, CV and MAE. Elevation profiles encompassing different land use types did not show significant contribution of vegetation. Since the forest is managed, less contribution were found from the understory stratum and the ground floor level. However, some outliers were found in abrupt topographic changes, requiring therefore manual edition. Further investigation should take into account the relief changes at different land use types and evaluate the impact of the topography on the extraction of individual trees.Pages: 6113-612
Avaliação da qualidade do produto Globcover para o Estado do Mato Grosso, Brasil, por meio de imagens do Google Earth e séries temporais de índices de vegetação derivados de imagens MODIS
No full textGlobcover is a global land cover map derived from an automated processing chain of 300m resolution MERIS time series and is provided as a major reference for applications such as climate and ecological modeling. The objective of this study was to validate the Globcover product for the State of Mato Grosso Brazil using Google earth images and temporal profiles of MODIS derived vegetation indices as a support to validate the landcover classes. The Vegetation Map Types produced by Radam Brasil Projects was used as an auxiliary information to check the mapping product. The procedure was divided into 4 steps: i) elaborating a random set of points for each class to validate the map; ii) translating landcover classes described in the Globcover Map into landcover classes as described in Radam Brasil Project; iii) extract temporal profiles of vegetation indices concerning the main landcover classes in the State of Mato Grosso iv) interpreting Google Earth images (reference data) to check the accuracy of Globcover classes. For each of the 16 classes evaluated it was sorted random samples totaling 108 points for the whole study area. Temporal profiles of Enhanced Vegetation Index (EVI 2) were selected from the Visualization of MODIS time-series for land use and landcover change analyses tool developed at National Institute for Space Research within the concept of a Virtual Laboratory of Remote Sensing in order to describe the main land use classes. These profiles can be used to describe the behavior of mapped classes along the period previous the mapping (2000 to 2011) and give support for interpretation of the high resolution imagery by its seasonal dynamics in future mappings. The confusion matrix resulted a kappa index of 0.43 and an overall accuracy of 0.47. These values are lower than those reported on the Globcover Products Description and Validation Report. The six main classes presented about 95% of the area of Mato Grosso State. Class 14 presented the larger area with about 50% of the total mapped and producer and user accuracies of 0.67 and 0.75, respectively. Temporal profiles of EVI showed that the classes describing single land cover types are properly defined since there is a well defined pattern of EVI profile. The classes describing a mixture of land cover types, showed similar temporal profiles of EVI and could not be well discriminated.Pages: 3486-349
Sistema de Alerta temprana de Incendios Forestales en México
No full textLa Comisión Nacional para el Conocimiento y Uso de la Biodiversidad (CONABIO) implementó el programa Detección de puntos de calor mediante técnicas de percepción remota en el año de 1999, en respuesta a la situación de emergencia registrada por los incendios forestales de la temporada de 1998. En la cual se registraron 14,445 incendios forestales afectando 849,632 hectáreas en el territorio mexicano (CONAFOR, 2012). Este programa ha evolucionado para convertirse en el Sistema de alerta temprana de incendios forestales. El sistema consiste de tres componentes asociados con las etapas de manejo de emergencias: antes (alerta temprana), durante (monitoreo de puntos de calor) y después (identificación de áreas quemadas). El sistema es utilizado por la Comisión Nacional Forestal, quien es la institución responsable de la atención de los incendios forestales.Pages: 6807-681
Discriminação de áreas cafeeiras de imagens multiespectrais da região de Três Pontas-MG através de Redes Neurais Artificiais e Extratores de Textura
No full textRemote Sensing Images show favorable to the study of spatial and temporal variations of the land surface. However the spectral information of these images may not be sufficient to discriminate objects that have similar pixel values as coffee areas and forests. An alternative is to use spatial attributes that consider the region and not only the pixel singly. In satellite images, coffee areas feature lines and shapes, whereas areas of natural vegetation are rough, irregulars and heterogeneous because of the various species of plants. Thus these two classes have different standards when it considers the regions itself and the texture was the spatial attribute chosen to be studied in this work. The application of the Artificial Neural Networks (ANNs) tends to be a promising approach for discrimination of classes of land use in satellite images. However, an ANN does not show a satisfactory performance when it uses only spectral data. In this work, it was developed a procedure for automatic pattern recognition using ANN and it was observed the potential of the inclusion of texture features in the class discrimination. The texture features were extracted from the LandSat5 image of the coffee region of Três Pontas, South of Minas Gerais. The ANN trained with the features of texture showed satisfactory performance proving that this kind of spatial attribute is significant in the discrimination of coffee areas and forests.Pages: 3795-380
Uso de geotecnologias para produção de carta de potencial geomorfométrico ao escoamento superficial
No full textRunoff processes are very important in the hydrological cycle and have strong influence over many of the physical processes on Earth surface. The runoff is frequently estimated by means of empirical techniques that consider aspects relating to relief and composition of earth materials. This paper propose a new automated methodology for obtaining a homogeneous hydrological zoning mapping based on geomorphometric potential from the digital terrain model. GIS tools were used to perform intermediate indexes: concentration index roughness (ICR), concentration index of drainage channels (ICCD) and concentration index gradients channels (ICGC). The intersection of these three index allows to carry out the Geomorphometric Runoff Potential Map. Comparing with Runoff Potential Map performed in traditional way the proposed map showed good agreement and more homogeneous distribution of runoff classes.Pages: 6252-625
Aplicação de redes neurais artificiais na identificação automatizada de coqueiros a partir de uma imagem de alta resolução
No full textMethods of pattern classification have been applied routinely in processing images obtained by remote sensing. Artificial neural networks are presented as an alternative computational method to traditional parametric classifiers and have been successfully used in remote sensing applications. This paper describes a case study supported by neural networks that aimed to recognize coconut trees present in a high resolution aerial image. Methodology was organized on two steps: image segmentation and recognition of coconut trees, both of wich were supported by Radial Basis Function and Growing Neural Gas neural networks. The Success rates achieved, above 80%, reinforce the hypothesis that neural networks are suitable methods for remote sensing applications.Pages: 7928-793
Origem tectônica de megaleques no norte da Amazônia com base em multisensores
No full textWe analyzed remote sensing data consisting of Landsat-5/TM (Thematic Mapper), Landsat-7/ETM+ (Enhanced Thematic Mapper Plus) and PALSAR images, and a Digital Elevation Model (DEM) derived from the Shuttle Radar Topography Mission (SRTM), in order to proceed with a morphostructural characterization of Quaternary megafan deposits in a large wetland area of northern Amazonia. The goal was to verify if the origin of this distributive alluvial paleolandscape that differs significantly from the modern fluvial tributary systems could be associated with tectonic subsidence. The data indicated several anomalous morphostructural features, consisting mostly of straight lineaments trending parallel to main faults from the adjacent crystalline basement, channel capture, orthogonal channel junctions, lateral deviation of megafan morphologies and of entire fluvial valleys, and termination of megafan in rectangular depressions bounded by straight lineaments. These features suggest that the formation of megafans in northern Amazonia was not random over a flat-lying area, but they were concentrated in pre-existing rectangular to wedge-shaped depressions formed by the combination of intrabasin normal and strike-slip faults. The presence of these depressions might have determined the development of distributary drainage systems and, consequently, the megafan geometries.Pages: 3580-358