National Institute for Space Research
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Avaliação da Qualidade Geométrica das Imagens RapidEye Ortorretificadas
No full textRapidEye imagery has quickly increased in importance for Brazilian users of remote sensing data, mainly due to its high temporal availability as well as special features related to spatial, spectral and radiometric resolutions. RapidEye imagery can be purchased in two processing levels: the first includes only radiometric correction and band-to-band registration; the second is an orthorectified product, which includes all previous corrections of the basic product. Recently, Brazilian government has purchased a complete territorial coverage under a special license that allows those images to be used for all federal government agencies, as well as environmental state agencies. This paper presents a case study on geometric evaluation of 3A RapidEye images. The main goal is to estimate their accuracy for localization purposes and measurements of distances, angles, and areas. The performed evaluation is divided, according to its nature, into relative and absolute. Relative evaluation is based on comparison of positions measured directly onto a set of multi-temporal 3A images, from which a set of parameters related to their relative accuracy and state of satellite constellation is estimated, while absolute evolution derived another set of parameters from the comparison of those positions with a set of control points measured over the terrain and used as ground truth. The obtained results in both relative and absolute evaluations showed a great temporal stability of the entire RapidEye constellation, as well as the high geometric quality of RapidEye images. Some evaluation parameters indicate their usability for mapping projects at scales greater or equal to 1:50.000.Pages: 1213-122
Proposta para avaliação da simbologia aplicada em mapas de uso do solo dos assentamentos paranaenses
No full textLand use maps are important tool for urban planning of cities and also for cadastre, monitoring and supervision of rural properties. This paper presents a proposal to evaluate the symbology used on land use maps of settlement projects of Agrarian Reform, located in the state of Parana. The main objective is to identify problems related to the currently symbology. The topic of this paper arose from the difficulties reported by some users of these maps in relation to reading and interpreting the information represented in them. The methodology shown comprises steps of description of the features contained in these maps with their respective symbols and a proposal for evaluation this symbology. The features shown on these maps can be divided into three themes, highlighting the classes of land use and features overlapping on these classes, as Permanent Preservation Areas and Legal Reserve areas. It is intended through the theory of thematic cartography, with emphasis on the study of visual variables, examine the application of these variables on the maps in question, in order to propose the most appropriate use of visual variables to represent the variation of each phenomenon present in these maps. As expected results, the goal is an improvement in the representation of the information in these maps, in order that, they can meet the needs of its users.Pages: 2157-216
Variação Sazonal da TSM do Atlântico Equatorial Ocidental a partir do Sensor AVRHH
No full textThe sea surface temperature (SST) in the equatorial Atlantic has variability over the years with many interacting processes in the region that is influenced by the dynamics of winds, currents, tides and discharge of the Amazon River. The present study is an analysis of SST near the northern coastal region, using AVHRR sensor monthly data aboard the NOAA satellite for the period of January 1998 to December 2007. It was possible to avaliate through this time series the SST behavior in space and time with an objective description of the images and quantify the time-scale variability by wavelets transformed. It was also analysed the correlations of SST data with OLR (Outgoing Longwave Radiation) and the flow of the Óbidos station to represent the Amazon River flow, in order to understand the processes that are related. The correlation between SST and OLR weren´t significant for the study period, the correlation between SST and low flow, indicating that the flow is not a dominant factor for the variability of SST of the northern waters of Brazil. The correlation between the SST anomalies for the three points, and the SST anomalies in the basin of the North and South Atlantic have clearly shown the influence of the dipole in the study area, suggesting that they are strongly associated.Pages: -781
Mapping burned area at the global scale using remotely sensed data under the fire_cci project: the SPOT-VGT algorithm
No full textWe introduce an algorithm for daily, global burned area map, at 1km spatial resolution, using imagery from the Système Probatoire dObservation de la Terre VEGETATION (SPOT-VGT) European satellite, developed under the framework of the European Space Agency (ESA) Climate Change Initiative, within the fire_cci project. The algorithm relies on time series analysis of near-infrared (NIR) reflectance at the single pixel level. The time series of are preprocessed to extract the minima values of each BRDF-induced oscillation, and then despiked using a robust filtering procedure. Potential burning dates are identified with the recently developed Pruned Exact Linear Time (PELT) change point detection approach. Multiple change points detected at each pixel are scored relatively to their likelihood of corresponding to a burning event. The dates of potential burn detection are also taken into account via the development of local fire climatologies described by fitting von Mises circular statistical distributions to MODIS active fire count data, and scored relatively to their timing of occurrence on the typical local fire season. The change point score and the date score are combined to yield a joint score and joint score maps are revised with a Markov Random field approach, to yield the final burned area maps. Accuracy of the SPOT-VGT burned area maps will be assessed against high spatial resolution imagery, prior to release to the public.Pages: 8736-874
Caracterização da paisagem da Sub-bacia do Rio da Prata-RS
No full text. Mankind continues to go through periods of great change which require it to dominate different areas and, as consequence, destroying and modifying the natural ecosystems. In this context, this work aims to characterize the landscape of the sub-basin of the river of Prata, RS. The satellite image was acquired by the National Institute of Spatial Research (INPE) and was processed and worked at software of Geographic Information Systems (GIS) IDRISI Selva. The indices of landscape ecology were calculated with the software Fragstat. As results it was found that natural fields and forest areas covers 50.61% of the total landscape, and agriculture areas and exposed soil occupy 46.43%. This exposed area could be soil prepared for agriculture or abandoned areas. The great majority of fragments (45.65%) have less than 1ha, and only 26.08% have core area, an important attribute to keep native fauna and flora species. This work could serve to better planning of land use in the river of Prata sub-basin and can be used as an example to be adopted by other regions like a planning tool for environmental decision making allowing for better use of natural resources.Pages: 6025-603
Uso de Geotecnologias para avaliação da agropecuária de Moçambique
No full textThe aim of this study was the use of geotechnology for generating maps and information that will subsidize the integrated management of the geographical space "Nacala Corridor" (North Zone) and "Maputo Corridor" (South Zone), as well as the diagnosis Mozambique's agriculture from surveys and organization of geographical database of natural resources and agricultural potential of agricultural information from government agencies, consulting and agricultural census and data validation in field in distinct missions in north and south of Mozambique. The results showed that building land use and land cover maps and detailed coverage, both in the north and south of Mozambique is hampered by the excessive number of small farms which represent 95% of the agricultural area of the country. The excessive occupation of agricultural land with basic food crops in small areas provides the formation of extensive agricultural landscapes that are often indistinct. This fact makes it impossible to distinguish any one continuous area of agricultural plant species. The identification of land use and land areas occurs only on large farms cultivate only exportation crops, especially sugar cane. However, the activities of data collection and field missions allowed the effective organization of the database in both Corridors as well as extensive knowledge of Mozambican agriculture and way of life of Mozambican farmers. Furthermore, it reveals the advantage of combining remote sensing with etno-agrnomic data colected in field in the study of land use/cover changes.Pages: 143-15
Aplicação de microtomografia computadorizada em estudos geológicos: a visualização 3D de estruturas rúpteis
No full textThis paper describes the methodology applied in five basalts samples from Serra Geral Formation, Santa Catarina State, Brazil, using images obtained by X-ray computed tomography (μCT), which allow 3D visualization. The rocks samples were oriented collected and sent to the Soil Imaging Laboratory - Guelph University, in Canada, for the images acquisition and processing. The steps for the enhancement of micro-brittle structures and mineral density differences, termed in this study as anisotropic markers, consist of filters to detect edges, smoothing filters and particle analysis. The results are shown in rose diagrams for each axis (X, Y and Z) of the samples and was established the relationship between the axis and the surface fault system. In order to evaluate whether the methodology can be applied to oriented rock without the fault surface, another set of images were analyzed, based on a subvolume of the samples, without the surface fault. The results showed that the new technology can be applied in oriented rock sample, even if the main fault system was not identified in the field, and the axis with the more homogeneous direction define the direction of the main fault system. Special attention has to be given to the presence of ring artifact that influences the results of the analysis.Pages: 3672-367
Mineração de dados para análise da cobertura florestal
No full textThe landscape ecology metrics associated with spectral and space data mining can be used to increase the potential of the analysis and applications of remote sensing data becoming an important tool for decision making. The present study sought to use data mining techniques and metrics of landscape ecology to classify and quantify the different types of vegetation present in São Luis do Paraitinga city, Sao Paulo, Brazil. The images went through object-oriented analysis through the plugin GeoDMA to obtain spectral and spatial data. This information was used to classify classes by decision trees. Eucalyptus and Forest fragment areas represented 8.6% and 36,1% of the total area, respectively. The decision tree generated by the classification algorithm was used to obtain the map of forest cover. The classification by decision tree showed kappa of 0.80, indicating little confusion. The results indicate the importance of the forest sector and contribute in studies to contain the impacts and problems caused by the expansion of eucalyptus plantations in the municipality. The generation of classifications by the method of data mining metrics associated with landscape ecology proved to be an affordable and reliable tool to extract the spatial and spectral data with remote sensing techniques. The method was efficient for the separation of forest classes and the metrics used were important to better understand the objects inserted in the landscape and the pressures they suffer.Pages: 2400-240
Criação de um sistema de informações geográficas na auditoria em cadastro de rede de distribuição elétrica
No full textOne of the great difficulties encountered in projects that require field survey is to see how the information collected is true and correct according to what actually exists, a fact that does not differ in registrations in electrical distribution networks. Promoting an internal audit conducted by the registration staff prior to delivery of the final product to the client, it becomes extremely important for the survival and completion of the project, not only because the amount of data collected is important, but also, and mainly , their quality, preventing re-field, creating unnecessary burdens and not expected to project. About this information the following work aimed to create a Geographic Information System, the SIGAUDIT, facing an audit in the data in the design of Survey and Update Data Asset Distribution Network of Electrical Centers Para - CELPA in one of the feeders Mains Municipality of Prainha in western Pará State, Brazil. From queries and spatial analysis, data adequacy and later the creation of thematic maps was possible to verify a range of probable errors found in the survey and thus correct them using GIS software developed by the open source Conselleria d'Infrastructures i Transports (CIT) of the Community of Valencia, gvSIG.Pages: 4016-402
Dinâmica dos incêndios florestais no Estado do Acre nas décadas de 90 e 00
No full textA floresta Amazônica esta perdendo sua característica de agir como barreira aos incêndios florestais. Esta vulnerabilidade aos incêndios tem sido estudado principalmente na região da Amazônia oriental onde as florestas estão mais fragmentadas, com mais alta taxa de ocupação e com gradiente de seca e impacto das mudanças climáticas mais sentido. Nós utilizamos o mapeamento anual para reconstruir o histórico de fogo da Amazônia Ocidental usando como exemplo a cena 002/67 do satélite Landsat que representa a órbita ponto mais antropizada do estado do Acre. Foi utilizado o Indice de Cicatriz de Fogo (Burn Scar Index BSI) derivado das frações de Material Fotossintético, Não-Fotossintético e Solo gerados pelo software Claslite©, para mapear os incêndios florestais nos últimos 21 anos (1989-2010). Este histórico de cicatrizes anuais indica que somente 22% ou 3.482 km2 das florestas Acreanas nesta região foi queimada ao longo dos anos. Estas florestas tiveram uma baixa frequência de fogo, sendo que 82% foi queimada somente uma vez, enquanto que 13% queimou duas vezes e o restante queimou até no máximo até 5 vezes neste período. A maioria destas áreas queimadas ocorreram em florestas abertas com bambu e em anos de forte El Nino (1992 e 1998) ou em anos de outros fenômenos climáticos como em 2005 e 2009. Estes resultados indicam que, como na Amazônia Oriental, as regiões mais antropizadas da Amazônia Ocidental também são sensíveis aos eventos climáticos de seca extrema, entretanto recentemente estas regiões tem tido aumento das áreas queimadas mesmo em anos de precipitação media normal. Isso indica uma mudança de peso na contribuição do desmatamento em detrimento dos efeitos do clima para a vulnerabilidade das florestas desta região ao fogo.Pages: 8799-880