Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Bibliography: leaves 305-312. / by William Henry Ledsham, Jr. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by Donald Charles Fyler. / M.S.

Este trabalho teve como objetivo avaliar as restrições e potencialidades ao uso turístico de parte da área do Parque Nacional Serra da Canastra (MG), na escala 1:50.000. Analisou-se a evolução temporal do uso e ocupação do solo e os impactos negativos ocasionados ao meio físico pela localização inadequada das vias de acesso. Por meio de técnicas de sensoriamento remoto, geoprocessamento e trabalhos de campo foram mapeadas as vias de acesso, delimitadas bacias hidrográficas com ordens hierárquicas iguais ou superiores a dois, realizadas análises de densidade de vias de acesso e canais de drenagem e elaborados produtos cartográficos básicos (modelo digital de elevação hidrologicamente consistente, carta de declividade, carta de distância vertical da drenagem mais próxima e mapas de uso e ocupação do solo de 1964/1967, 1989 e 2009). Estes resultados foram combinados a trabalhos de outros autores para elaboração dos seguintes documentos interpretativos: carta de restrição à implantação de vias, carta de predisposição a movimentos de massa, carta de suscetibilidade à inundação de planícies, carta de suscetibilidade à ocorrência de incêndios e carta de trafegabilidade. Com base nestes documentos interpretativos, foram obtidos os níveis de suscetibilidades e restrições das bacias hidrográficas mapeadas. A partir de critérios de classificação, foram adotadas cinco classes de adequabilidade ao uso turístico. De modo geral, as bacias hidrográficas mostraram-se bastante restritivas a este uso, 81% foram classificadas como semi-adequadas ou inadequadas e apenas 19% como adequadas. Não foram identificadas bacias que se enquadravam como totalmente adequadas ou totalmente inadequadas. Apesar de prevalecerem condições de restrição ao uso turístico da área de estudo, estas não necessariamente inviabilizam a sua utilização para o turismo. A partir dos documentos interpretativos, que apresentam suscetibilidades e restrições, o uso turístico da área pode ser melhor planejado, de maneira a reduzir impactos e riscos. Em relação à evolução temporal do uso e ocupação do solo na área de estudo, o mapeamento mostrou que não ocorreram grandes mudanças ao longo dos períodos analisados, contudo houve uma pequena melhora na preservação das formações florestais. As vias de acesso também não apresentaram um aumento significativo no período compreendido entre 1989 e 2009. Quanto aos impactos negativos causados ao meio físico, as rodovias de tráfego periódico mostraram-se mais preocupantes quanto ao desenvolvimento de processos erosivos que os caminhos/trilhas, devido a sua localização sobre materiais inconsolidados mais suscetíveis à erosão. No entanto, os caminhos/trilhas podem ser deflagradores de outros impactos pela concentração do escoamento superficial, como assoreamento dos corpos dágua, aumento da turbidez e vazão dos rios. / This study had the objective of evaluating the potentialities and restrictions regarding the touristic use of Serra da Canastra region (MG), in scale 1:50.000. The temporal evolution and soil occupation were analyzed as well as the negative impacts caused to the environment due to improper location of the access roads. The access roads were mapped through remote sensing, geoprocessing and field work, the hydrographic Basins were delimited with hierarchical order equal or higher than second hierarchical order, access road and drain canal density analysis was performed, and basic cartographic products were done (digital model of hydrologically consistent elevation, slope map, vertical distance of the nearest drain and the soil use and occupation in 1964/1967, 1989 and 2009). These results were combined on the study of other authors in order to have the following interpretative documents: restriction map to the road implementation, mass movement predisposition map, susceptibility to floodplains map, susceptibility to fire map, and trafficability map. Based on those interpretative documents, susceptibility and restriction levels were obtained to the mapped watersheds. These levels were used to define the criteria for classification of the watersheds in five classes of suitability for the tourist use. In general, the watersheds showed very restrictive to this use, 81% were classified as semi-suitable or unsuitable and only 19% as suitable. No watershed was considered completely suitable or unsuitable. Although conditions to restriction regarding the touristic use of the study area remain, those do not necessarily stop its use to the tourism. From the intermediate products, which present susceptibility and restrictions, the touristic use of the area can be better planned, in such a way to reduce impacts and risks. Regarding the temporal evolution of the soil use and occupation in the study area, the mapping has shown that big changes along the analyzed periods have not occurred, however there was a small improvement when it comes to preserving the forest formation. The road access did not present a significant increase between 1989 and 2009 either. Regarding the negative impacts caused to the environment, the traffic roads presented as more worrying about the development of erosive processes than the paths, due to its location on more susceptible to erosion unconsolidated materials. However, the paths may trigger other impacts because of the concentration of superficial flowing, such as drainage channels silting, increase of turbidity and river discharge.

O emprego de câmeras digitais multiespectrais torna possível a utilização de índices de vegetação, obtidos por meio de operações matemáticas entre bandas espectrais de uma mesma imagem. Estes índices podem ser empregados na estimativa de produtividade de culturas agrícolas e no delineamento de zonas de manejo, por apresentarem relação com o vigor da cultura. Algumas variáveis obtidas no campo, como o índice de área foliar (IAF), a altura de plantas e o número de plantas por metro linear, também podem ser empregadas na avaliação do vigor da cultura. O objetivo principal deste trabalho foi avaliar imagens obtidas por meio de videografia aérea digital multiespectral, quanto ao seu potencial na estimativa da produtividade e na determinação de zonas de manejo em culturas de grãos. As imagens foram adquiridas por meio de uma câmera de vídeo digital multiespectral (Duncantech MS3100). Também foram utilizados mapas de produtividade, referentes a duas áreas cultivadas, primeiramente com trigo, no inverno de 2001, e na seqüência com soja, no verão de 2002. Além disso, foi realizado um trabalho de campo, na cultura da soja, em uma das áreas de estudo, onde foram determinados, em uma grade amostral, o índice de área foliar, a altura de plantas e o número de plantas por metro linear. As imagens aéreas foram corrigidas geometricamente e normalizadas radiometricamente no software Idrisi32, após o que foi realizada uma regressão linear simples entre as imagens e os mapas de produtividade, pixel-a-pixel e com as imagens classificadas. Os dados coletados em grade foram analisados por meio da estatística descritiva e da geoestatística, sendo posteriormente interpolados, gerando os mapas de superfície das variáveis estudadas. Os mapas de superfície criados para as variáveis medidas no campo apresentaram elevada correlação entre sí. A imagem NDVI apresentou uma melhor relação com a estimativa de produtividade, quando comparada com as imagens das bandas espectrais individualizadas, do vermelho e do infravermelho próximo. Concluiu-se que as imagens aéreas digitais multiespectrais obtidas por videografia são eficientes na estimativa da produtividade de grãos quando existe elevada variabilidade nas imagens e as mesmas não apresentam valores discrepantes. Também proporcionam informações importantes ao delineamento de zonas de manejo. / The utilization of multispectral digital cameras makes it possible the use of vegetation indices, generated by means of mathematical operations between spectral bands from the same image. These indices can be used to estimate crop yields and delineate management zones due to the relation between them and crop vigor. Some variables, measured on the field, such as leaf area index (LAI), plants height and plants per linear meter, can also be used in the assessment of the crop vigor. The main objective of this work was to evaluate multispectral digital aerial videographic images regarding their potential in crop yield estimate as well as in management zones delineation. The images were acquired with a multispectral digital camera (Duncantech MS3100). Yield maps were also used, for two cropped areas, firstly with wheat, in the 2001 winter, and afterwards, with soybean, in the 2002 summer. Moreover, a field work was accomplished, for soybean, in one of the study areas. Three variables were measured, on a sampling grid: leaf area index, plants height and plants per linear meter. The aerial images were geometrically rectified and radiometrically normalized, in the software Idrisi32, and then a simple linear regression was performed between images and yield maps, pixel-by-pixel and with the classified images and maps. Data collected on the sampling grid were analyzed by means of descriptive statistics and also geostatistics. After an interpolation procedure, surface maps of these variables were generated. The surface maps generated for the variables measured on the field presented high correlation among themselves. The NDVI image showed a better relation with yield estimate than the individual spectral bands, red and near infrared. One can conclude that the multispectral digital aerial videographic images are efficient for grain crops yield estimates, when there is a high variability on the images, without outliers. These images can also provide important information to the management zones delineation.

A elaboração de modelos pode ser entendida como um processo de simplificação da realidade. Desta forma, foram utilizados neste trabalho dados multitemporais estatísticos e de sensoriamento remoto, para que fossem caracterizadas as mudanças nos padrões de uso e cobertura da terra na bacia do Taiaçupeba nos últimos 30 anos. Para uma melhor aferição das informações obtidas a partir de imagens de satélite e uma posterior verificação das mesmas, foi necessária a utilização de dados colhidos durante levantamentos de campo, bem como o uso de estatísticas oficiais e trabalhos científicos sobre a área de estudo, dando ao presente trabalho um papel de complementação e atualização desses últimos. / Modeling is the process that makes reality simpler. Thus multitemporal statistics and remote sensing data were applied to this work, so that the land use and cover pattern changes in Taiaçupeba basin could be traced during the past 30 years. For a better checking of the remote sensing acquired information and its later comparison, it was necessary to use field data, as well the official statistics and earlier scientific works about the area, which was complemented and updated by this work.

Global demand for agricultural products is an increasingly important driver of deforestation in the Amazon Basin. This dissertation examines the consequences of agricultural expansion for stream ecosystems in the southern Amazon's agricultural frontier. At regional scales, the removal of watershed forest cover is known to change the energy balance and influence hydro-climatic cycling by altering stream flow, regional rainfall patterns, and land surface temperatures. At the landscape scale, these physical changes may be further exacerbated by land management practices that lead to the degradation of riparian forest buffers; decreases in connectivity; changes in the amount of light, nutrient, and sediment inputs; and decreases in water quality. Together, land use and management influence the quality and distribution of aquatic habitats within stream networks, potentially decreasing stream biotic integrity and resilience to further disturbances. Brazil's Mato Grosso state is one of the most actively expanding agricultural frontiers in the world and represents an ideal case study for examining the linkages among tropical deforestation, agricultural expansion, and the conservation of freshwater ecosystems. Mato Grosso accounted for 40% of deforestation in the Brazilian Amazon during the early 2000s - primarily due to the expansion of soybeans and cattle ranching. Deforestation rates have since dropped throughout the Amazon, but there is a lack of spatially explicit information about the land use transitions accompanying this decline. To address this gap, I combined government data on deforestation and production with the MODIS satellite time series to quantify the spatial-temporal dynamics of land use change in the region. Although agricultural expansion during this period slowed with declining commodity prices, the decline in deforestation is partly explained by a shift from soybean expansion into forests (26% of expansion from 2001-2005) to expansion into already cleared pasture lands (9% of expansion form 2006-2010). Beyond documenting these trends, the resulting dataset is a critical first step in evaluating the influence of land use and land use history on freshwater ecosystems at multiple scales. In the headwaters region of the Xingu River Basin, the proportion of small watersheds (microbasins) dominated by agriculture (>60% of area) increased from 20 to 40% from 2001 to 2010. At the same time, the stream network became increasingly fragmented by the removal of riparian forest buffers and installation of farm impoundments. I used high resolution satellite data (ASTER) to produce the first landscape-level documentation of farm impoundments in the region, mapping approximately 10,000 impoundments (one per 7.6 km of stream length) in 2007. At the catchment scale, I collected field data in 12 headwater streams to examine the effect of land management on instream water quality. Watershed forest cover (from MODIS), the density of impoundments (from ASTER), and the percent forest in upstream riparian buffers (from Landsat) were all associated with substantial increases in stream temperature. These increases in fragmentation and water temperature may have large cumulative effects on the stream network and reduce the ability of downstream protected areas to conserve freshwater resources. At the scale of the Amazon Basin, my analysis indicates that 30% of indigenous lands and protected areas are highly vulnerable to future reductions in hydrologic connectivity, simply because of their location within their watersheds. These impacts could be substantially mitigated through enforcement of existing legislation to protect riparian buffers and new regulations to limit the number of impoundments in emerging agricultural landscapes.

L’anticipation des effets des changements climatiques nécessite une bonne compréhension dufonctionnement carboné des écosystèmes continentaux. L’une des principales contraintes liées àl’étude de ces écosystèmes est la forte variabilité à la fois spatiale et temporelle de leurs flux decarbone et de leurs réponses aux contraintes abiotiques. L’usage de méthodes de télédétectionoptiques pourrait permettre de suivre de façon spatialisée le fonctionnement des couverts végétaux.Ce travail vise à évaluer le potentiel de méthodes de télédétection pour décrire la structure et lefonctionnement de couverts végétaux à des échelles spatiales et temporelles variées. Pour ce faire,les relations entre indices optiques et phénomènes biologiques ont été étudiées en suivant unedémarche de transfert d’échelle, des échelles les plus fines aux plus larges. Il a été montré que le PRI(Photochemical Reflectance Index), utilisé en tant qu’indicateur du LUE (Light Use Efficiency), est parnature un signal composite qui reflète principalement la régulation du rendement de laphotosynthèse sur des échelles de temps fines, et la structure et composition biochimique ducouvert à l’échelle de la saison. L’analyse de courbes de réponse du PRI au PAR (PhotosyntheticallyActive Radiation) a permis de déconvoluer ces deux sources de variabilité, via l’introduction duconcept de PRI0 ou PRI d’une feuille idéalement adaptée à l’obscurité. Ce PRI0, capturant la variabilitédu PRI indépendante du LUE, a pu être mesuré à l’échelle de la feuille, et estimé à l’échelle de jeunescouverts végétaux et de la parcelle. Cette variabilité a pu être expliquée à l’échelle de la feuille et dejeunes couverts végétaux par les variations du contenu en pigment des feuilles. A l’échelle depeuplements adultes et de l’année, elle résulte cependant d’effets combinés de la compositionbiochimique et de la structure des couverts qui n’ont pu être séparés. Ces effets sont susceptiblesaux échelles larges de masquer en bonne partie, voire de biaiser la relation entre PRI et LUE. Il a enoutre été montré que la représentativité du PRI est limitée aux strates supérieures des canopées etdépend de la structure du couvert et du climat lumineux, ce qui peut limiter son intérêt en tantqu’estimateur du LUE à l’échelle de l’écosystème. Ces résultats soulignent la nécessité de prendre encompte la structure et la composition biochimique des couverts végétaux dans le cadre d’uneutilisation du PRI en tant que proxy du LUE de l’écosystème. / In order to assess the effect of global warming, a good understanding of carbon functioning ofterrestrial ecosystems is needed. The study of terrestrial ecosystem carbon fluxes and responses toabiotic stress remain challenging due to their high spatial and temporal variability. The use of remotesensing may help us to describe those sources of variability. The aim of this work is to assess thepotential of remote sensing as a way to describe canopy structure and functioning over a broadrange of temporal and spatial scales. The relationships between optical indices and biologicalphenomenon were investigated over a range of increasing scales. The PRI (PhotochemicalReflectance Index), used as a proxy of the LUE (Light Use Efficiency) was shown to be a compositesignal, mainly impacted by the regulation of the LUE at short time scales, and by canopy structureand pigment content at seasonal scale. The analysis of PRI response to PAR (PhotosyntheticallyActive Radiation) allowed us to deconvolve those two sources of variability thanks to theintroduction of the PRI0 defined as the PRI of ideally dark adapted leaves. The PRI0 was shown toefficiently describe the LUE unrelated PRI variability, and could be measured at leaf scale, andestimated at the leaf, canopy and stand scales. This variability could be explained by changes in leafpigment content over the growing season at leaf and canopy scales. At the stand scale and over theyear, this LUE independent PRI variability resulted from combined effects of canopy structure andpigment content, which could not be separated. These effects may result in biased or masked PRIversus LUE relationships at larges scales. Moreover, it was shown that the in-situ PRI measurementsmainly responded to the LUE of sunlit leaves, depending on canopy structure and sky conditions. Thismay considerably hamper the use of the PRI as a proxy of the whole ecosystem LUE. These resultsillustrate the need to take canopy structure and pigment content into account while using the PRI asa proxy of the ecosystem LUE.

Este trabalho tem como objetivo apresentar o sistema óptico desenvolvido para a câmera WFI (Wide Field Imaging Camera) que integrará os satélites CBERS 3 e 4 (China Brazil Earth Resources Satellite). O Brasil é responsável por duas das câmeras dos satélites CBERS 3 e 4, a WFI e a MUX (Multispectral Camera). Estas câmeras são destinadas a sensoriamento remoto orbital da Terra. É a primeira vez que câmeras destinadas a este tipo de aplicação são inteiramente desenvolvidas e construídas no país. Devido ao alto nível de vibração durante o vôo, à exposição a vácuo e a radiação espacial durante o período de vida útil em órbita, o desenvolvimento desta câmera exige um cuidadoso processo de análise e avaliação do desempenho óptico em terra de modo a garantir seu funcionamento a bordo. Em especial, serão apresentados as análises ópticas realizadas durante a fase de projeto preliminar e os testes ópticos realizados em terra dos requisitos: distância focal, campo de visada - FOV, função de transferência de modulação - MTF, distorção, sensibilidade à polarização, transmitância, sensibilidade à luz espalhada e degradação da transmitância com a radiação espacial. Os resultados obtidos comprovaram que o desempenho do sistema óptico atende os requisitos de projeto. / The purpose of this work is to present the optical system developed for the WFI camera (Wide Field Imaging Camera), which will be integrated to the CBERS 3 and 4 satellites (China Brazil Earth Resources Satellite). Brazil is responsible for two cameras of CBERS 3 and 4 satellites, WFI and MUX (Multispectral Camera). These cameras are used for orbital remote sensing of the Earth. It is the first time that cameras for this type of application are being entirely developed and built in our country. Due to the high vibration level during flight, the vacuum and space radiation exposure during the lifetime in orbit, the development of this camera requires a meticulous analysis process and evaluation of optical performance on the ground in order to ensure the effective operation on board. In particular, the optical analyses performed during the preliminary design and optical test requirements performed on ground will be presented, such as: focal length, field of view - FOV, modulation transfer function - MTF, distortion, polarization sensitivity, transmittance, stray light sensitivity and transmittance degradation with space radiation. The results obtained exhibit that the optical system performance satisfies all project requirements.

No description available.

Wild leek (Allium tricoccum) is a spring ephemeral of northeastern North America. In the Canadian province of Quebec, it is listed as threatened due to human harvesting, and in Gatineau Park its presence is used as an indicator of human impact. Wild leek grows in patches on the forest floor, and before the tree canopy develops its green leaves are clearly visible through the bare branches of deciduous forests, allowing it to be observed with optical remote sensing. This study developed and tested a new method for monitoring wild leek across large geographic areas by integrating field observations, UAV video, and satellite imagery. Three-cm resolution orthomosaics were generated for five <0.1 km2 sites from the UAV video using Structure-from-Motion, segmented, and classified into wild leek (WL) or other (OT) surface types using a simple greenness threshold. The resulting maps, validated using the field observations, had a high overall accuracy (F1-scores between 0.64 to 0.94). These maps were then used to calibrate a linear model predicting the per-pixel percentage cover of wild leek (%WL) from NDVI in the satellite imagery. The linear model calibrated for a Sentinel-2 image from 2018, covering all of Gatineau Park (~361 km2), allowed %WL to be predicted with an RMSE of 10.32. A similar model calibrated for a WorldView-2 image from 2018 was noisy (RMSE = 37.64), though much improved by resampling this image to match the spatial resolution of Sentinel-2, due to MAUP scale effect (RMSE = 13.06). Testing the potential for satellite-based monitoring of wild leek, the %WL prediction errors were similar when a new linear model was developed using the Sentinel-2 image from 2017 (RMSE = 12.84) and when the model calibrated with the 2018 Sentinel-2 image was applied to the 2017 satellite data (RMSE = 16.97). The linear models developed for the Sentinel-2 and WorldView-2 images from 2018 were used to map wild leek cover for Gatineau Park. Both images allowed production of similar wild leek maps that, based on field experience and visual inspection of the imagery, provide good descriptions of the actual distribution of wild leek at Gatineau Park.