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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

A comparison of high spatial resolution images for fine scale vegetation mapping /

West, Christine. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 38-43). Also available via Humboldt Digital Scholar.
42

Modelling and mapping potential hooded warbler (Wilsonia citrina) habitat using remote sensing /

Pasher, Jonathan. January 1900 (has links)
Thesis (M.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 125-133). Also available in electronic format on the Internet.
43

Quantification of reservoir operation-based losses to floodplain physical processes and impact on the floodplain vegetation at the Kootenai River, USA /

Benjankar, Rohan Man. January 1900 (has links)
Thesis (Ph. D., Civil Engineering)--University of Idaho, August 2009. / Major professor: Klaus Jorde. Includes bibliographical references. Also available online (PDF file) by subscription or by purchasing the individual file.
44

Vegetation mapping and estimation of the extent of near-surface permafrost in Mackenzie Delta, Northwest Territories /

Nguyen, Thai-Nguyen, January 1900 (has links)
Thesis (M.SC.) - Carleton University, 2007. / Includes bibliographical references (p. 136-146). Also available in electronic format on the Internet.
45

Estimation of seedling density and evaluation of woody competition in young loblolly pine plantations using 35mm color aerial photography

Heer, Richard C. January 1986 (has links)
The potential for using large scale, small format aerial photography to obtain seedling density and woody competition information was investigated. Factors affecting photo interpretation of seedlings were examined and equations to predict seedling density and woody competition levels were developed and evaluated. Two scales of imagery, 1:4000 and 1:6000 were considered to compare their relative merits for these purposes. Greater age of the seedlings and their inherent development generally served to improve photo interpretation. The amount of woody competition present in the plots tended to hinder seedling identification at the 1:4000 scale, while enhancing it when 1:6000 scale data was used. Seedling density estimation and evaluation of competition through Free-To-Grow classification predictions yielded results comparable to ground surveys. Estimation of total groundline basal area in all woody competition, and classification of the plots by the amount of hard-to-control competition they contained, were less successful. These results may have been due in part to the partial leaf fall that occurred prior to obtaining the imagery. Many of the results found in this study favored the larger scale (1:4000) imagery, and its use for the procedures described is recommended. / M.S.
46

Use of ancillary data in a Landsat classification of a forested wetland

Prisley, Stephen P. January 1982 (has links)
Digital Landsat cover-type classifications have often proved less accurate than hoped for, or have been less detailed than needed. Recent research efforts have used additional data to supplement the four bands of Landsat MSS data in an attempt to increase the accuracies of computer classifications. The goal of this study was to evaluate the use of vegetation-related ancillary variables for improving the performance of a Landsat classification of the Great Dismal Swamp. Ancillary data considered to be related to the distribution of vegetation types in the swamp were registered with Landsat multispectral scanner data to a 50 meter UTM grid. The ancillary variables were peat depths and elevations from field surveys, and spectral texture values from the Landsat data. Discriminant analyses of a sample of pixels were performed to investigate the ability of spectral and ancillary data, separately and in combination, to discriminate between vegetation cover types. A layered classification procedure was developed that used discriminant analysis of ancillary data after a previous unsupervised spectral classification. This was compared to a spectral stratification classification and a straightforward unsupervised classification of spectral data alone. The layered procedure resulted in an accuracy of 21.46% for level III classes and 41.71% for level II classes. The accuracies for level III and level II classifications using the unsupervised procedure were 41.58% and 63.77%, respectively. Some possible explanations of the seemingly contradictory results were posed, and alternative procedures suggested. / Master of Science
47

Hybrid image classification technique for land-cover mapping in the arctic tundra, North Slope, Alaska

Chaudhuri, Debasish. January 1900 (has links)
Dissertation (Ph.D.)--The University of North Carolina at Greensboro, 2008. / Title from PDF t.p. (viewed Aug. 10, 2009). Directed by Roy Stine; submitted to the Dept. of Geography. Includes bibliographical references (p. 154-165).
48

Mapping of Sonoran Desert Vegetation Communities and Spatial Distribution Differences of Larrea Tridentata Seed Density in Relation to Ambrosia Dumosa and Ambrosia Deltoidea, San Cristobal Valley, Arizona

Shepherd, Ashley Lauren January 2011 (has links)
Vegetation in the San Cristobal Valley of Barry M. Goldwater Range-East was mapped using a combination of field surveys and aerial imagery interpretation to contribute to ongoing inventory of natural resources for the BMGR-East as well as assist in resource management decisions. Eighteen vegetation associations were identified and mapped through collection of 186 samples to characterize vegetation associations. The most common vegetation association was Larrea tridentata monotype, covering 29% of the area mapped. Larrea tridentata is a widely spread shrub throughout the Sonoran, Chihuahuan and Mojave deserts; therefore understanding germination and seedling survival patterns is crucial. Ambrosia dumosa and A. deltoidea exhibit nurse plant-protégé interactions with L. tridentata. Seed density of L. tridentata was studied under Ambrosia species to determine factors controlling germination and seedling density. As expected seed density was greater under Ambrosia canopy than areas with no canopy. Ambrosia species and canopy type did not affect seed density.
49

Análise da dinâmica de fragmentos florestais : estudo de caso de Sorocaba-SP /

Bortoleto, Ludmila Araújo. January 2014 (has links)
Orientador: Alexandre Marco da Silva / Banca: Welber Senteio Smith / Banca: Cassio José Montagnani Figueira / Resumo: As mudanças na paisagem causadas por fatores antrópicos geram grandes impactos sobre os ecossistemas. Uma das principais alterações que vem acontecendo é a substituição da vegetação nativa por outros formas de cobertura, resultando num cenário de fragmentação da vegetação natural que resta. Neste trabalho, avaliou-se quantitativamente e qualitativamente os fragmentos florestais remanescentes no município de Sorocaba, utilizando mapas digitais de cobertura da terra de duas épocas (1988 e 2011) gerados a partir de imagens de satélite. As métricas da paisagem como tamanho dos fragmentos, distância entre eles e efeito de borda, foram calculadas. Analisou-se também a qualidade da cobertura da terra conforme a intensidade de uso humano e o potencial de percolação na matriz. Os resultados apresentaram que apesar da alta variação da paisagem, ocorreu um aumento da área de Vegetação Natural Remanescente/Reflorestamento. Houve também um grande aumento da área urbana em 18,1%. O número de fragmentos florestais diminuiu em 161 fragmentos no período. Contudo, notou-se que os fragmentos estão maiores em áreas. A distância entre os fragmentos teve sua maior variação na classe <100m, sugerindo haver uma maior conectividade entre eles. Apesar da proximidade entre os fragmentos, eles estão sob efeito de borda, e a tendência se manteve para o período de estudo. A qualidade da cobertura da terra mostrou que a paisagem do município passou por um processo de transformação induzido por atividades antrópicas. Além disso, o potencial de percolação da classe não habitat revelou dados tabulares que sugerem preocupação com as áreas onde há intensificação de uso humano e, ainda, mapas com regiões importantes que favorecem a recomposição da paisagem. De forma geral, o estudo se torna base para o conhecimento da paisagem local e dá sustentabilidade para a tomada de decisões quanto ao planejamento ambiental e urbano do... / Abstract: Changes in the landscape provoked by anthropogenic factors usually cause that threat for ecosystems. One important change that has occurring is the replacement of native vegetation by other kinds of land cover, resulting in a fragmentation process of the remaining vegetation. Here we investigated the dynamic of the land cover change, as well as the dynamic of patches of the natural remnant vegetation (NRV) in the Sorocaba municipality - Brazil for a period of 23 years (1988 and 2011) using digital land cover maps, which were generated from satellite images. Several landscape metrics as fragment size, distance between them and also edge effect were calculated. The quality of land use was also analyzed, according to the intensity of human use, and percolation potential in the matrix. The results showed that despite the high variation in the landscape, there was an increase in the area of remaining vegetation. There was also an expressive increase in the urban area 18.1%. The number of forest fragments declined in 161 fragments in the period. However, it was noted that the fragments are denser. The distance among the fragments had a greater variation in class < 100m, suggesting that there was greater connectivity among them. Despite the connectivity among the fragments, they are under edge effect, and the trend continued for the period of study. Through the quality of land use, it was verified that the landscape of the city experimented a process of transformation induced by anthropogenic activities. Moreover, the potential percolation of non habitat area revealed tabular data that suggest concern about areas where there intensification of human use and also with important regions that favor the restoration of the landscape. Overall, the study becomes the basis for knowledge of the local landscape and provides sustainability for making decisions about the environmental and urban planning of Sorocaba city / Mestre
50

Using multiple resolution digital images and GIS to determine vegetation sampling locations at Whiskeytown National Recreation Area /

McGovern, Ian Patrick. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2008. / Includes bibliographical references (leaves 53-55). Also available via Humboldt Digital Scholar.

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