National Institute for Space Research
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Satellite-based relationships between malaria vector density and environmental drivers in Portugal
No full textMalaria is a vector borne disease responsible for thousands of deaths around the world each year. Malaria was endemic in Europe up to 1950s and, although the current risk is considered minimal, environmental changes can lead to malaria resurgence. In this study we analyze and quantify the relationships between temperature and landscape and the most efficient malaria vector in Southern Europe: An. Atroparvus. For that purpose we use remote sensing derived data and show the spatio-temporal patterns of potential risk of malaria resurgence in Portugal.Pages: 8530-853
Determinación de la deforestación en los Bosques Secos del Santuario Histórico de Pómac
No full textThe north coast of Peru has the best preserved portion of Equatorial Dry Forest Ecoregion, with the Forest Historical Sanctuary Pómac your sample more representative and emblematic. The Historical Sanctuary Pomac Forest is established in the Lambayeque Region, Peru. It is a natural area protected by the Peruvian State, part of the National System of Natural Protected Areas - SINANPE and is administered by the Ministry of Environment, through the National Service of Natural Protected Areas (SERNANP). Will worked with the bands 3, 4 and 5 of the TM/Landsat sensor of the years 2000, 2006 and 2008, which we had used the 2000 (orthorectified) as a reference for georeferencing the 2006 and 2008. Then we cut the images according to the study area and, which were segmented using a region growing algorithm, which divides the image into regions which are considered in a set of contiguous pixels that have a certain uniformity, trying with thresholds of similarity testing of 6, 8 and 10 and area 20 and 30. In the classification stage was used the supervised algorithm based on Bhattacharya distance with a threshold of acceptance of 95%, providing training samples that were representative for each class, validating the information with the control points provided by SERNANP. Selected classes were Forest, Not Forest and Hydrography. The results were optimal accuracies being higher than 85% in all three cases, demonstrating the responsiveness of the Bhattacharya algorithm in the detection of deforestation in different forest types.Pages: 2996-300
Detección de la salinidad de los suelos en los cultivos de algodón usando imágenes ASTER, TM y ETM+ en la cuenca de zaña, costa norte del Perú
No full textThe objective of this work is the detection of soil salinity with the use of the images of reflectance of soil of the sensor ASTER, TM and ETM + and its validation with in situ data of soil electrical conductivity (EC) of the study areas the Vineyard, San Antero, Saltur and Úcupe located in the basin of Zaña the North Coast of Peru. Satellite images from the sensor ASTER, TM and ETM + were processed using the software ENVI 4.5 and IDL. We used principal component analysis (PCA), the rate of salt (IndSal), the Normalized Difference Vegetation Index (NDVI) and spectral reflectance images. We applied the multiple linear regression analysis to the data in situ EC, principal components (PC) of the bands, the index of salt (IndSal), Normalized Difference Vegetation Index (NDVI) and the reflectance spectral of soil. For The Viña was used images ASTER, ETM + and TM getting a correlation coefficient of -0.87, -0.89 and -0.80 respectively. For San Antero, Saltur and Ucupe use an image TM and obtained correlation coefficients of -0.92, -0.75 and -0.82 respectively.Pages: 1525-153
Análise preliminar da dinâmica de inundação na cidade de Boa Vista-Roraima
No full textBoa Vista city has experienced a population increase accelerated in last 30 years and as result presents a contrasting urban landscape. This urbanization process interact synergistically regional biogeophysical features and makes the city susceptible to inundation events in rainy season. In this context, present study aimed analyze the inundation dynamics in Boa Vista city. For this, had conducted a preliminary mapping of flooded areas by 2011 inundation event, through data integration extracted from satellite images, topographical maps and field visits. These data analysis allowed to evaluate the urban expansion process and topographical condition of the city well as to characterize the inundation dynamics. With the integration of this information have been generated maps of flooded areas mainly related to floodplain Branco and Cauamé river, lakes, drainage and igarape mouths that cross urban city area. Then, it is concluded that the topographical condition flat of Boa Vista becomes the city susceptible to slow or fluvial inundations. Others types of inundations are related with elevation of water level lakes occupied irregularly and fluvial backwater in mouth of paved igarapes. The holistic and spatial view of this process can serve as a basis for surveys more detailed to formulate strategies to manage those events.Pages: 882-88
Visualização e Geometria de Mapas em Perspectiva de Cidades Disponíveis na Internet
No full textNowadays, there is a growing offer of high resolution mosaics of satellite images which compose image maps, in browsers on the internet (such as Google Maps or Bing Maps), beyond cartographic basis of geographic information from public and private institutions made available for consultation. The image maps of big cities in high resolution even allow the view of the facades of the buildings and can be classified as oblique or perspective maps, which are easier to interpret than traditional maps with orthogonal projection. However, as most images used in mosaics are from satellites, selected from a previously existing database, the azimuths and inclination angles of the views are different and in many cases, dont allow a good visualization of tall elements, such as skyscrapers. Also, the perspective effect chosen by the user is not informed, what may be necessary if the map is used to measure distances. This article analyses the types of geometric perspectives used in oblique maps and found in the cities image maps, as well as the optimum visualization conditions according to the recommendations of cartography and technical drawing rules. It also shows that the visualization in true perspective is only possible in systems with 3D data handling resources. Key words: Oblique digital images, perspective maps, 3D maps, imagens digitais oblíquas, mapas em perspectiva, mapas 3D.Pages: 2141-214
Mapeamento do uso e ocupação do solo do município de Feira de Santana, Bahia
No full textThe result of spatial dynamics and the different factors that impact on the territory are reflected directly in the use and occupation of ground. Map and analyze key patterns of use and occupation of ground in the county of Feira de Santana - Bahia was the object of this study, which used images of Landsat sensors and RapidEye, with the final product characterization of different types of occupation verified, beyond composition of a georeferenced database, with the main features of the current standard of occupation of the county, represented in a thematic map base produced at 1:50,000 scale. We identified ten classes of use (Irrigated agriculture, Agriculture, Urban area, Country-houses and small farms, secondary forest, lake / pond / dam / river, pasture, Eucalyptus cultivation, Exposed soil / withdrawal of material and Caatinga vegetation). The class was predominantly agriculture, pastures and crops formed by temporary alternate seasonally. The map was drawn with the index validated and confirmed with the Kappa-PABAK coefficient, obtaining an excellent accuracy.Pages: 7398-740
Evaluation of the temporal dynamics of spectral indices and their relationship with biophysical variables on wheat for the purpose of yield estimation
No full textEarly crop yield estimation is extremely relevant to assist on management decisions and to plan harvest logistics and commercialization. The purpose of this study is to evaluate the ability of widely reported spectral indices to estimate leaf area index (LAI) and total above ground biomass (DW) through the season, and their capacity to provide useful information for crop yield estimation. Particular emphasis is placed in identifying indices that can estimate the biophysical parameters of crops that accumulate large amounts of DW and LAI. The study site located in the south west of Uruguay was planted with wheat cultivar Biointa1006. From emergence until maturity the site was imaged approximately every 15-20 days with a UAV carrying a multispectral camera with channels in the green, red and NIR regions. Three indices were estimated, NDVI, NDVIgreen, CIgreen. Approximately at the same date of the flight sampling points were visited, DW and LAI were measured. The evolution of indices resembled the evolution of LAI and DW accumulation. CI_green was the index that discriminated better differences in LAI at zadoks 4.7, while NDVI showed a diminished ability to reflect increments in LAI after zadoks 3.0. Results suggest that there is a trade off among indices, between indices that show a tight relationship to biophysical variables but loose sensitivity at larger LAI or DW, and those that maintain sensitivity but present more error. Further analysis is necessary to confirm these hypotheses and evaluate different methods of yield estimation based on remote sensing and biophysical models combined.Pages: 39-4
Identificação do desmatamento através da análise comparativa do Normalize Difference Vegetation Index (NDVI) e Ratio Vegetation Index (RVI) no município de Juiz de Fora - MG
No full textThe vegetation indices are used in various areas of remote sensing. They are mainly used in environmental studies interested in doing analysis on land cover in a certain region. This study has as objective to compare two types of vegetation indices in rural Juiz de Fora (MG). This comparison will be done with images georeferenced. The proposed work can provide data for monitoring and prevention of common deforestation in the region. The reason of deforestation has been: creating new roads, mains, pipes for sanitation and urban sprawl. The data analyzed in the LANDSAT TM sensor - 5 which make it possible to monitor natural resources. The comparison between the vegetation index (NDVI) and ratio vegetation index (RVI) is performed on an area in a given time period. This comparison allows the identification of biomass and its spatial distribution for auxiliary information in many geographical information systems to date and accurate fashion. The results showed that the images with the values of RVI and NDVI are very similar; however the NDVI has better clarity to target classes. The RVI detected almost twice deforested areas, which makes the NDVI a more reliable indicator, also shows an important tool in the identification of plant biomass.Pages: 4411-441
Resposta espectral dos índices EVI e NDVI dos bancos de macrófitas em lagos de meandro abandonado na região do Rio Purus, AM
No full textThe objective of this study was to analyze the feasibility of using multi-temporal images of Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) for the distribution of aquatic macrophytes in different seasons. The analyzes were done in eight abandoned meander lakes near the Purus River, between Boca do Acre and Pauini, AM. We estimated species richness and coverage of macrophytes during 2012. Seasonal values of vegetation indices at a 250 m resolution were obtained from the average value of the images of 16-day composition MOD13 A1 product, between January 2001 to September 2012. We sampled four pixels of each lake. Data analysis tests included NMDS, PERMANOVA, ANOVA and Person correlation. Results indicated a correlation between the coverage area of macrophytes (EVI r = 0.5 and NDVI r = 0.4) and ecological groups (EVI r = 0.4 and r = 0.5 NDVI). EVI had more significant relation to macrophyte coverage (p = 0.01) while the NDVI responded ecological groups (p = 0.009). The influence of macrophytes in seasonal cycles was evident in temporal fluctuation of the indices NDVI and EVI.Pages: 3183-319
Avaliação e dimensionamento das propostas de continuidade para o Sistema Brasileiro de Coleta de Dados Ambientais
No full textThe Brazilian Environmental Data Collection System provides data collection services based on SCD-1 and SCD-2 satellites to an increasing user community. The SCD-1, with 19 years in flight operation, operates in a degraded mode as well as SCD-2 with 14 years in operation. If the data collection service is stopped as a consequence of SCD-1 or SCD-2 failure, many users specially National Water Agency will be impacted with lack of data and economic impacts due to remote installed platform replacement such as in Amazon region. The National Hydrometeorological network imposes additional demands for revisit time and coverage. To satisfy these new demands, a working group was established by AEB, ANA, and INPE to provide analysis and configuration proposals for the microsatellite constellation that have a revisit time lower than 1 hour and covering any Brazilian region. After selection of the simulated constellation solutions, another task was performed so that technical and economic benefits and impacts could be estimated for each one of the options, including launching costs. The cost and time estimation considers degrees of the Brazilian industry participation in the development of satellite constellation. The paper also describes additional requirements imposed to a satellite such as the need to have a propulsion subsystem as well as an attitude control subsystem to maintain the satellite constellation in the correct phase. The cost estimation is a kind of tool to help or to guide the selection of a solution to be adopted for system expansion or continuity.Pages: 9078-908