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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.
51

Mapping of Sonoran Desert Vegetation Communities of San Cristobal Valley and Southern Sentinel Plains, Barry M. Goldwater Range AND Variables Influencing Route Proliferation in the Barry M. Goldwater Range's San Cristobal Valley

Whitbeck, Douglas Craig January 2013 (has links)
The vegetation associations in the Eastern San Cristobal Valley of Barry M. Goldwater Range-East (BMGR) were mapped using a combination of field surveys (relevés) and interpretation of aerial imagery in order to contribute to ongoing mapping efforts of Barry M. Goldwater Range-East. Throughout the San Cristobal Valley, 149 relevé samples were collected to characterize the vegetation associations. Seventeen vegetation associations were identified and mapped, including a new Larrea tridentata/Ambrosia dumosa/Grusonia kunzei (Creosote bush-White bursage-Devil's cholla) association. Accuracy assessment of the map was conducted using a contingency table finding the map to be 82% accurate. Route proliferation in the San Cristobal Valley of Barry M. Goldwater Range-East (BMGR) was also mapped and measured using remotely sensed imagery in geographic information systems and modeled with geographical variables in a multivariate regression. Throughout the San Cristobal Valley study site, 6,878 km of unauthorized routes were identified. Geographic explanatory variables distance from slopes greater than 34% (b = -3.252e-5, p<0.001) and the most influential variable distance from unauthorized routes (b = -0.006568, p<0.001) were tested for significance and influence in predicting unauthorized route density. The resulting model, built from the two significant geographic variables in a multivariate regression, was able to explain 57% of the variability in the data. The results from this study have shown that through the use of GIS and remote sensing, unauthorized route density can be predicted by geographic variables which can then be used to make future route management decisions.
52

Collection of endmembers and their separability for spectral unmixing in rangeland applications

Rolfson, David, University of Lethbridge. Faculty of Arts and Science January 2010 (has links)
Rangelands are an important resource to Alberta. Due to their size, mapping rangeland features is difficult. However, the use of aerial and satellite data for mapping has increased the area that can be studied at one time. The recent success in applying hyperspectral data to vegetation mapping has shown promise in rangeland classification. However, classification mapping of hyperspectral data requires existing data for input into classification algorithms. The research reported in this thesis focused on acquiring a seasonal inventory of in-situ reflectance spectra of rangeland plant species (endmembers) and comparing them to evaluate their separability as an indicator of their suitability for hyperspectral image classification analysis. The goals of this research also included determining the separability of species endmembers at different times of the growing season. In 2008, reflectance spectra were collected for three shrub species (Artemisia cana, Symphoricarpos occidentalis, and Rosa acicularis), five rangeland grass species native to southern Alberta (Koeleria gracilis, Stipa comata, Bouteloua gracilis, Agropyron smithii, Festuca idahoensis) and one invasive grass species (Agropyron cristatum). A spectral library, built using the SPECCHIO spectral database software, was populated using these spectroradiometric measurements with a focus on vegetation spectra. Average endmembers of plant spectra acquired during the peak of sample greenness were compared using three separability measures – normalized Euclidean distance (NED), correlation separability measure (CSM) and Modified Spectral Angle Mapper (MSAM) – to establish the degree to which the species were separable. Results were normalized to values between 0 and 1 and values above the established thresholds indicate that the species were not separable . The endmembers for Agropyron cristatum, Agropyron smithii, and Rosa acicularis were not separable using CSM (threshold = 0.992) or MSAM (threshold = 0.970). NED (threshold = 0.950) was best able to separate species endmembers. Using reflectance data collected throughout the summer and fall, species endmembers obtained within two-week periods were analyzed using NED to plot their separability. As expected, separability of sample species changed as they progressed through their individual phenological patterns. Spectra collected during different solar zenith angles were compared to see if they affected the separability measures. Sample species endmembers were generally separable using NED during the periods in which they were measured and compared. However, Koeleria gracilis and Festuca idahoensis endmembers were inseparable from June to mid-August when measurements were taken at solar zenith angles between 25° – 30° and 45° – 60°. However, between 30° and 45°, Bouteloua gracilis and Festuca idahoensis endmembers, normally separable during other solar zenith angles, became spectrally similar during the same sampling period. Findings suggest that the choice of separability measures is an important factor when analyzing hyperspectral data. The differences observed in the separability results over time also suggest that the consideration of phenological patterns in planning data acquisition for rangeland classification mapping has a high level of importance. / xii, 93 leaves : ill. (some col.) ; 29 cm
53

Urban Vegetation Mapping Using Remote Sensing Techniques : A Comparison of Methods

Palm, Fredrik January 2015 (has links)
The aim of this study is to compare remote sensing methods in the context of a vegetation mapping of an urban environment. The methods used was (1) a traditional per-pixel based method; maximum likelihood supervised classification (ENVI), (2) a standard object based method; example based feature extraction (ENVI) and (3) a newly developed method; Window Independent Contextual Segmentation (WICS) (Choros Cognition). A four-band SPOT5 image with a pixel size of 10x10m was used for the classifications. A validation data-set was created using a ortho corrected aerial image with a pixel size of 1x1m. Error matrices was created by cross-tabulating the classified images with the validation data-set. From the error matrices, overall accuracy and kappa coefficient was calculated. The object-based method performed best with a overall accuracy of 80% and a kappa value of 0.6, followed by the WICS method with an overall accuracy of 77% and a kappa value of 0.53, placing the supervised classification last with an overall accuracy of 71% and a kappa value of 0.38. The results of this study suggests object-based method and WICS to perform better than the supervised classification in an urban environment.
54

Remote sensing-based identification and mapping of salinised irrigated land between Upington and Keimoes along the lower Orange River, South Africa /

Mashimbye, Zama Eric. January 2005 (has links)
Thesis (MSc)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.
55

Predictive mapping of landtype association maps in three Oregon national forests /

Peterman, Wendy L. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 44-50). Also available on the World Wide Web.
56

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

Bortoleto, Ludmila Araújo [UNESP] 04 June 2014 (has links) (PDF)
Made available in DSpace on 2015-03-03T11:52:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-06-04Bitstream added on 2015-03-03T12:07:01Z : No. of bitstreams: 1 000803320.pdf: 1396713 bytes, checksum: 9e5ef599d92bbbeade83f7eda640d30c (MD5) / 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... / 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
57

Estudo da cobertura vegetal nativa da bacia do rio Ocoy, oeste do Paraná: subsídios para a implantação de um corredor de biodiversidade entre o Parque Nacional do Iguaçu e o Lago de Itaipu

Seganfredo, Diogo 27 March 2015 (has links)
Este estudo objetivou avaliar aspectos da estrutura da paisagem relacionados à conservação da biodiversidade em uma microbacia situada em região de importância estratégica para a implantação do Corredor de Biodiversidade do Rio Paraná. Os mapas foram elaborados a partir de imagens de satélite e manipuladas no software de geoprocessamento Spring. A partir do mapa de uso e cobertura do solo gerou-se 4 diferentes cenários: situação real (vegetação atual), considerando efeito de borda (faixa de 50 m entorno dos fragmentos como borda), sem as Áreas de Preservação Permanente – APP (desconsiderou-se a existência das APPs) e o cenário com a restauração de todas as APPs (de acordo com a legislação vigente). Com base em métricas da paisagem analisou-se os resultados do uso e cobertura da terra e dos demais cenários. Os resultados indicaram que o uso predominante é agricultura e 24,6% da área total estudada é composta por vegetação natural, sendo que o maior remanescente possui 315,3 ha. As APPs ocupam 3,1% da área de estudo e 75% dessas áreas estão cobertas com cobertura vegetal natural. Os outros 25% restantes da APP encontram-se sem vegetação. Os resultados mostraram que ao considerar o efeito de borda nos remanescentes restaram apenas 28% como área central, no cenário em que se desconsiderou a presença das APPs gerou-se grande impacto na fragmentação, com diminuição na área da classe e aumento no número de fragmentos. No cenário que se considerou a restauração de APPs faltantes promoveu-se aumento na conectividade efetiva da paisagem, a partir dos resultados do índice de PROX. Desta forma, concluiu-se que as APPs possuem papel fundamental na conectividade de fragmentos florestais. A avaliação dos cenários mostrou que ações de restauração com abrangência espacial restrita em áreas de preservação permanente podem resultar em um expressivo aumento da conectividade da paisagem. / This study aimed to evaluate features of landscape structure related to the conservation of biodiversity in a watershed located in strategically important region for the implementation of the Paraná River Biodiversity Corridor. The maps were made from satellite images and manipulated in the Spring GIS software. From the land use and land cover map 4 different scenarios were generated: real situation (current vegetation), considering edge effect (50 m surrounding the fragments as edge), without the Permanent Preservation Areas - PPA (dismissed the existence of the PPAs) and the scenario with the restoration of all PPAs (according to the Brazilian Forest Code). Based on landscape metrics the results of the land use and land cover and other scenarios were analyzed. The results indicated that the predominant land use is agriculture and 24.6% of the total study area consists of natural vegetation, and the largest remnant has 315.3 ha. The PPAs occupy 3.1% of the study area and 75% of these areas are covered with natural vegetation. The other remaining 25% of PPA have no vegetation. The results showed that when the edge effect in the remnants was considered it remained only 28% as the central area; in the scenario that the presence of PPAs was disregarded it was generated a great impact in fragmentation, with a decrease in the area of class and increase in the number of fragments. In the scenario that considered the missing PPAs restoration it was promoted an increase in the effective connectivity of the landscape, from the results of the PROX index. Thus, PPA have a fundamental function in connecting forest fragments. The evaluation of the scenarios showed that the restoration of small areas of PPAs, according to the Brazilian Forest Code, could generate strong benefits for the landscape connectivity.
58

Estudo da cobertura vegetal nativa da bacia do rio Ocoy, oeste do Paraná: subsídios para a implantação de um corredor de biodiversidade entre o Parque Nacional do Iguaçu e o Lago de Itaipu

Seganfredo, Diogo 27 March 2015 (has links)
Este estudo objetivou avaliar aspectos da estrutura da paisagem relacionados à conservação da biodiversidade em uma microbacia situada em região de importância estratégica para a implantação do Corredor de Biodiversidade do Rio Paraná. Os mapas foram elaborados a partir de imagens de satélite e manipuladas no software de geoprocessamento Spring. A partir do mapa de uso e cobertura do solo gerou-se 4 diferentes cenários: situação real (vegetação atual), considerando efeito de borda (faixa de 50 m entorno dos fragmentos como borda), sem as Áreas de Preservação Permanente – APP (desconsiderou-se a existência das APPs) e o cenário com a restauração de todas as APPs (de acordo com a legislação vigente). Com base em métricas da paisagem analisou-se os resultados do uso e cobertura da terra e dos demais cenários. Os resultados indicaram que o uso predominante é agricultura e 24,6% da área total estudada é composta por vegetação natural, sendo que o maior remanescente possui 315,3 ha. As APPs ocupam 3,1% da área de estudo e 75% dessas áreas estão cobertas com cobertura vegetal natural. Os outros 25% restantes da APP encontram-se sem vegetação. Os resultados mostraram que ao considerar o efeito de borda nos remanescentes restaram apenas 28% como área central, no cenário em que se desconsiderou a presença das APPs gerou-se grande impacto na fragmentação, com diminuição na área da classe e aumento no número de fragmentos. No cenário que se considerou a restauração de APPs faltantes promoveu-se aumento na conectividade efetiva da paisagem, a partir dos resultados do índice de PROX. Desta forma, concluiu-se que as APPs possuem papel fundamental na conectividade de fragmentos florestais. A avaliação dos cenários mostrou que ações de restauração com abrangência espacial restrita em áreas de preservação permanente podem resultar em um expressivo aumento da conectividade da paisagem. / This study aimed to evaluate features of landscape structure related to the conservation of biodiversity in a watershed located in strategically important region for the implementation of the Paraná River Biodiversity Corridor. The maps were made from satellite images and manipulated in the Spring GIS software. From the land use and land cover map 4 different scenarios were generated: real situation (current vegetation), considering edge effect (50 m surrounding the fragments as edge), without the Permanent Preservation Areas - PPA (dismissed the existence of the PPAs) and the scenario with the restoration of all PPAs (according to the Brazilian Forest Code). Based on landscape metrics the results of the land use and land cover and other scenarios were analyzed. The results indicated that the predominant land use is agriculture and 24.6% of the total study area consists of natural vegetation, and the largest remnant has 315.3 ha. The PPAs occupy 3.1% of the study area and 75% of these areas are covered with natural vegetation. The other remaining 25% of PPA have no vegetation. The results showed that when the edge effect in the remnants was considered it remained only 28% as the central area; in the scenario that the presence of PPAs was disregarded it was generated a great impact in fragmentation, with a decrease in the area of class and increase in the number of fragments. In the scenario that considered the missing PPAs restoration it was promoted an increase in the effective connectivity of the landscape, from the results of the PROX index. Thus, PPA have a fundamental function in connecting forest fragments. The evaluation of the scenarios showed that the restoration of small areas of PPAs, according to the Brazilian Forest Code, could generate strong benefits for the landscape connectivity.
59

Using Classification and Regression Tree and Valley Bottom Modeling Techniques to Identify Riparian Vegetation in Pinal County, Arizona

Hickson, Benjamin 01 January 2015 (has links)
The ecological value and functionality of riparian systems along ephemeral, intermittent, and perennial streams in the Southwest is well established. In Pinal County, Arizona the existing datasets available to environmental managers and governing bodies drastically underestimate the extent and presence of riparian zones. This study addresses the issue through the use of remote sensing land cover classification techniques. Landsat 8 data, topographic data, and high-resolution color infrared (CIR) imagery, and several derived vegetation indices are used to construct a classification and regression tree (CART) model. Using training data, the CART model is used for the identification and delineation of basic land cover classes across the County. Woody annual and perennial species are identified and associated to riparian zones using a valley bottom model (VBM) developed by the United States Department of Agriculture. The CART model (kappa value of 0.76) found that 929 square-miles of annual vegetation and 651 square-miles of perennial vegetation are present across Pinal County. Annual and perennial vegetation classifications are assessed for density using a 0.33 acre moving window. The density values for both classes are then used in conjunction to differentiate upland, xeroriparian, mesoriparian, and hydropriarian vegetation zones. Vegetation zones are clipped to regions where the VBM identifies valley bottom probability to be 62 percent or greater. The results generated provide a sufficiently comprehensive dataset that gives County managers and environmental professionals improved insight into the presence and distribution of important riparian habitats.
60

Vegetation description and mapping along a strip transect in central Namibia with the aid of satellite imagery

Strohbach, Marianne Margarethe 02 August 2007 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MSc (Botany))--University of Pretoria, 2007. / Plant Science / MSc / unrestricted

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