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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.
811

An interface between the GRASS geographic information system and ORACLE relational detabase management system

Buker, David Gordon 30 November 1993 (has links)
A query and display interface has been developed between the GRASS geographic information system and the SQL-based ORACLE relational database management system (DBMS) . This interface enables multiple non-spatial attributes of GRASS map features to be maintained with the DBMS. GRASS alone is capable of storing only one attribute per feature. The interface allows the user to provide both spatial (GRASS) and non-spatial (SQL) selection criteria for any query. Spatial selection methods include picking items from the GRASS map with a mouse, and specifying areas of interest with user-drawn (via a mouse) polygons and transects. The results of the combined query are displayed both graphically (the selected GRASS map features are highlighted in a graphics window) and textually (the DBMS attribute data are shown in a text display window). Options include creating reclassified maps based on the DBMS output, and updating the attributes retrieved by a query.
812

A multiscale remote sensing assessment of subtropical indigenous forests along the wild coast, South Africa

Blessing, Sithole Vhusomuzi January 2015 (has links)
The subtropical forests located along South Africa’s Wild Coast region, declared as one of the biodiversity hotspots, provide benefits to the local and national economy. However, there is evidence of increased pressure exerted on the forests by growing population and reduced income from activities not related to forest products. The ability of remote sensing to quantify subtropical forest changes over time, perform species discrimination (using field spectroscopy) and integrating field spectral and multispectral data were all assessed in this study. Investigations were conducted at pixel, leaf and sub-pixel levels. Both per-pixel and sub-pixel classification methods were used for improved forest characterisation. Using SPOT 6 imagery for 2013, the study determined the best classification algorithm for mapping sub-tropical forest and other land cover types to be the maximum likelihood classifier. Maximum likelihood outperformed minimum distance, spectral angle mapper and spectral information divergence algorithms, based on overall accuracy and Kappa coefficient values. Forest change analysis was made based on spectral measurements made at top of the atmosphere (TOC) level. When applied to the 2005 and 2009 SPOT 5 images, subtropical forest changes between 2005-2009 and 2009-2013 were quantified. A temporal analysis of forest cover trends in the periods 2005-2009 and 2009-2013 identified a decreasing trend of -3648.42 and -946.98 ha respectively, which translated to 7.81 percent and 2.20 percent decrease. Although there is evidence of a trend towards decreased rates of forest loss, more conservation efforts are required to protect the Wild Coast ecosystem. Using field spectral measurements data, the hierarchical method (comprising One-way ANOVA with Bonferroni correction, Classification and Regression Trees (CART) and Jeffries Matusita method) successfully selected optimal wavelengths for species discrimination at leaf level. Only 17 out of 2150 wavelengths were identified, thereby reducing the complexities related to data dimensionality. The optimal 17 wavelength bands were noted in the visible (438, 442, 512 and 695 nm), near infrared (724, 729, 750, 758, 856, 936, 1179, 1507 and 1673 nm) and mid-infrared (2220, 2465, 2469 and 2482 nm) portions of the electromagnetic spectrum. The Jeffries-Matusita (JM) distance method confirmed the separability of the selected wavelength bands. Using these 17 wavelengths, linear discriminant analysis (LDA) classified subtropical species at leaf level more accurately than partial least squares discriminant analysis (PLSDA) and random forest (RF). In addition, the study integrated field-collected canopy spectral and multispectral data to discriminate proportions of semi-deciduous and evergreen subtropical forests at sub-pixel level. By using the 2013 land cover (using MLC) to mask non-forested portions before sub-pixel classification (using MTMF), the proportional maps were a product of two classifiers. The proportional maps show higher proportions of evergreen forests along the coast while semi-deciduous subtropical forest species were mainly on inland parts of the Wild Coast. These maps had high accuracy, thereby proving the ability of an integration of field spectral and multispectral data in mapping semi-deciduous and evergreen forest species. Overall, the study has demonstrated the importance of the MLC and LDA and served to integrate field spectral and multispectral data in subtropical forest characterisation at both leaf and top-of-atmosphere levels. The success of both the MLC and LDA further highlighted how essential parametric classifiers are in remote sensing forestry applications. Main subtropical characteristics highlighted in this study were species discrimination at leaf level, quantifying forest change at pixel level and discriminating semi-deciduous and evergreen forests at sub-pixel level.
813

GIS implementation as a decision support tool for planning and managing development interventions / Implementing GIS as a decision support tool for planning and managing development interventions

Jong, Yungong Theophilus January 2011 (has links)
The aim of this study is to examine key implementation and managerial issues surrounding the use of a Geographic Information Systems (GIS) as a Decisions Support Tool (DST) for planning and managing development interventions. Ever since the emergence of GIS as a powerful analytical tool in almost all spheres of human endeavour, many organisations involved in development work have adopted its use. But the challenges of conceiving and implementing a GIS in ways that are more responsive to the problems that trigger its purchase remains a daunting task to many development organisations; even those with a wealth of experience in GIS. This is one of the motivating factors for this study. In this research, some relevant themes in GIS implementation and GIS management as a Spatial Decision Support System (SDSS) were examined in the literature review. A case study research strategy was used focusing on the experience of the Nelson Mandela Bay Municipality Enterprise GIS (EGIS). The study examined how the system is been ran and what other development organisations can learn from this experience. Data was collected and analysed using a mixed research methods approach. The findings show a good level of GIS acceptance among municipality staff. However, running the system is not hitch free. A couple of problems and challenges were identified on the field. It is recommended that the municipality like most development organisations seeking GIS solutions should put the user at the centre of every technical innovation in GIS as a DST.
814

Adaptive user interfaces for mobile map-based visualisation

Van Tonder, Bradley Paul January 2008 (has links)
Mobile devices today frequently serve as platforms for the visualisation of map-based data. Despite the obvious advantages, mobile map-based visualisation (MMV) systems are often difficult to design and use. Limited screen space, resource constraints and awkward interaction mechanisms are among the many problems with which designers and users have to contend. Adaptive user interfaces (AUIs), which adapt to the individual user, represent a possible means of addressing the problems of MMV. Adaptive MMV systems are, however, generally designed in an ad-hoc fashion, making the benefits achieved difficult to replicate. In addition, existing models for adaptive MMV systems are either conceptual in nature or only address a subset of the possible input variables and adaptation effects. The primary objective of this research was to develop and evaluate an adaptive MMV system using a model-based approach. The Proteus Model was proposed to support the design of MMV systems which adapt in terms of information, visualisation and user interface in response to the user‟s behaviour, tasks and context. The Proteus Model describes the architectural, interface, data and algorithm design of an adaptive MMV system. A prototype adaptive MMV system, called MediaMaps, was designed and implemented based on the Proteus Model. MediaMaps allows users to capture, location-tag, organise and visualise multimedia on their mobile phones. Information adaptation is performed through the use of an algorithm to assist users in sorting media items into collections based on time and location. Visualisation adaptation is performed by adapting various parameters of the map-based visualisations according to user preferences. Interface adaptation is performed through the use of adaptive lists. An international field study of MediaMaps was conducted in which participants were required to use MediaMaps on their personal mobile phones for a period of three weeks. The results of the field study showed that high levels of accuracy were achieved by both the information and interface adaptations. High levels of user satisfaction were reported, with participants rating all three forms of adaptation as highly useful. The successful implementation of MediaMaps provides practical evidence that the model-based design of adaptive MMV systems is feasible. The positive results of the field study clearly show that the adaptations implemented were highly accurate and that participants found these adaptations to be useful, usable and easy to understand. This research thus provides empirical evidence that the use of AUIs can provide significant benefits for the visualisation of map-based information on mobile devices.
815

The use of Geographical Information Systems for the promotion of spatial cognition, spatial perspective taking and problem solving in school level geography

Britz, Hendrina Wilhemina January 2013 (has links)
A question asked at the United States of America (USA) National Council for Geographic Education (NCGE) conference in 1967, namely, what learning does GIS allow that other ways do not and whether teaching GIS at school level is worth the time and effort required to implement it, remains largely unanswered. Literature searches suggest that little more has been done since 1967 to investigate the effectiveness of GIS in education, or that there are any findings to suggest that GIS is worth the time and effort to implement in schools. Internationally the implementation of GIS software and geo-spatial data in schools has been slow, and South Africa is no exception. The main reasons given for slow implementation internationally have included lack of resources, lack of training and lack of time. The majority of secondary schools that offer Geography in the Port Elizabeth Education District, South Africa, teach GIS theory without the use of GIS software and geo-spatial data. The purpose of this research was to elicit the perceptions of secondary school level Geography teachers and learners of the benefits, barriers and obstacles to implementing GIS software and geo-spatial data as a teaching strategy. As a focused exercise to investigate what learning using GIS allows that other ways do not, this study also investigated whether using GIS as a teaching and learning strategy enables the promotion of learners spatial cognition, spatial perspective taking and problem solving abilities better than traditional methods do. The findings are viewed through the lens of developing Crystallized Intelligence (Gc), Spatial Intelligence (Gv) and Fluid Intelligence (Gf), respectively. The study followed a concurrent transformative mixed methods design with pre-post testing and the use of crossover experimental and control groups to generate both qualitative and quantitative data. Questionnaires aimed at all secondary Geography teachers in the Port Elizabeth Education District were used to assess how GIS is taught in their schools and to evaluate their perceptions of the benefits and barriers of implementing GIS software and geo-spatial data in the classroom. Four secondary school Geography teachers in four schools volunteered to take part in the experimental aspects of the study. Empirical data on the development of spatial cognition, spatial perspective taking, and problem solving were generated via pre- and post-tests in which the grade 11 Geography learners participated. Experimental and comparison groups of learners wrote four different types of pre- and post-tests where the experimental groups worked on GIS software with geo-spatial data while the comparison groups used traditional methods. Teacher interviews and learner interviews were also conducted to assess attitudes towards GIS software and geo-spatial data as a teaching strategy. The results from this aspect of the study mirrored the benefits and barriers to implementing GIS in schools recorded in international literature. However, and possibly more importantly, the empirical data generated by the learners revealed that GIS software and geo-spatial data do statistically significantly promote better spatial cognition (Crystallized Intelligence) and spatial perspective taking (Spatial Intelligence) than traditional methods do (i.e. using atlases, rulers and calculators). No improvement was found in the experimental groups‟ problem solving abilities. This report offers possible explanations and recommendations in terms of socio-cultural findings from other educational studies on the effects of exploratory talk on the development of Fluid Intelligence. Recommendations are made for the attention of curriculum developers, teachers, school principals, departmental officials and other educational stakeholders in terms of what is required for the successful implementation of GIS software and the use of geo-spatial data in secondary school Geography classes.
816

Arctic Shipping in Canada: Analysis of Sea Ice, Shipping, and Vessel Track Reconstruction

Pizzolato, Larissa Anna Vincenza January 2015 (has links)
Declining sea ice area in the Canadian Arctic has gained significant attention with respect to the prospect of increased shipping activities along the Northwest Passage and Arctic Bridge shipping routes. Temporal trend and correlation analysis was performed on sea ice area data for total, first-year ice (FYI), and multi-year ice (MYI), and observed shipping activity within the Vessel Traffic Reporting Arctic Canada Traffic Zone (NORDREG zone) from 1990 to 2012. Relationships between declines in sea ice area and Arctic maritime activity were investigated alongside linkages to warming surface air temperatures (SAT) and an increasing melt season length. Statistically significant increases in vessel traffic were observed on monthly and annual time-scales, coincident with declines in sea ice area. Despite increasing trends, only weak correlations between the variables were identified, suggesting that other non-environmental factors have likely contributed to the observed increase in Arctic shipping activity including tourism demand, community re-supply needs, and resource exploration trends. As a first step towards quantifying spatial variability in shipping patterns, a case study was conducted using 2010 observed shipping data to reconstruct historical shipping routes using a least cost path (LCP) approach. This approach was able to successfully reconstruct vessel tracks compared to an independent data source (Automatic Identification System) to an accuracy of 10.42 km ± 0.67 km over the entire study area. A 25 km gridded product across the entire Canadian Arctic domain was produced for 2010, with this approach now providing a basis to apply this method over the entire record (since 1990) in future studies to investigate long term spatial variability and change of shipping activity across the Canadian Arctic.
817

Requirements of a web-based geographic information system clearinghouse

Mearns, Martie Alèt 12 September 2012 (has links)
M.Inf. / Users of geographic information systems (GIS) are often faced with a challenge with regard to identification, location and overall access to digital data used in the application of GIS. The selection of the appropriate data from the large volumes available, also gaining access to available data and the establishment of the distribution of data from one central source are necessary tasks in order to improve the dissemination of GIS data. However, these are difficult tasks due to many users being unaware of the full range of available digital GIS data. A mechanism that could assist in improving access to digital GIS data is the Webbased GIS clearinghouse. This study was initiated to determine the requirements of GIS clearinghouses for optimum accessibility to digital GIS data. A literature study was conducted to investigate the nature of data that is used in GIS clearinghouses, the current trends in GIS data on the Web and the unique characteristics of the Web that can increase accessibility to digital GIS data. A selection of clearinghouses was made and these were evaluated in order to determine variables that can be translated into criteria from which a model for the evaluation of GIS clearinghouses could be established. This model can act as a working document or check-list for users to evaluate GIS clearinghouses, or for designers to create new or improve existing GIS clearinghouses.
818

Developing a Wildlife Tracking Extension for ArcGIS

Chen, Cai 05 1900 (has links)
Wildlife tracking is an essential task to gain better understanding of the migration pattern and use of space of the wildlife. Advances in computer technology and global positioning systems (GPS) have lowered costs, reduced processing time, and improved accuracy for tracking wild animals. In this thesis, a wildlife tracking extension is developed for ArcGIS 9.x, which allows biologists and ecologists to effectively track, visualize and analyze the movement patterns of wild animals. The extension has four major components: (1) data import; (2) tracking; (3) spatial and temporal analysis; and (4) data export. Compared with existing software tools for wildlife tracking, the major features of the extension include: (1) wildlife tracking capabilities using a dynamic data layer supported by a file geodatabase with 1 TB storage limit; (2) spatial clustering of wildlife locations; (3) lacunarity analysis of one-dimensional individual animal trajectories and two-dimensional animal locations for better understanding of animal movement patterns; and (4) herds evolvement modeling and graphic representation. The application of the extension is demonstrated using simulated data, test data collected by a GPS collar, and a real dataset collected by ARGOS satellite telemetry for albatrosses in the Pacific Ocean.
819

GIS application in emergency management of terrorism events on the University of North Texas campus.

Tsang, Yuenting 08 1900 (has links)
This thesis presents a Web-based geographic information system (GIS) application for campus emergency management that allows users to visualize, integrate, and analyze student population, facilities, and hazard data for efficient emergency management of University of North Texas before, during, and after a terrorism event. End-users can locate and search the source area of an event on a digital map from the ArcIMS-based Website. The website displays corresponding population information and attributes of impacted facilities in real time. School officials and first responders including police, firefighters and medical personnel can promptly plan the appropriate rescue and response procedures according to the displayed results. Finally, the thesis outlines the limitations of Web-based GIS in the arena of campus emergency management.
820

Estudo dos acidentes de trânsito com vítimas na cidade de Rio Claro, São Paulo com suporte das técnicas de geoprocessamento / Study of traffic accidents with victims in the city of Rio Claro, Sao Paulo, with the support of geoprocessing techniques

Vedovato, Maria Aparecida, 1953- 22 August 2018 (has links)
Orientador: Roberto Wagner Lourenço / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-22T10:12:00Z (GMT). No. of bitstreams: 1 Vedovato_MariaAparecida_D.pdf: 5142794 bytes, checksum: 851d9f50d427029a2ae0f28c1fc7f77d (MD5) Previous issue date: 2013 / Resumo: Atualmente, os acidentes de trânsito matam em todo o mundo mais de um milhão de pessoas por ano e deixam feridas entre 20 milhões e 50 milhões de pessoas. Os jovens representam a maioria das vítimas, que, muitas vezes, apresentarão seqüelas pelo resto da vida (DETRAN/RS, 2007). Neste contexto, o objetivo deste trabalho foi estudar os acidentes de trânsito com vítimas na área urbana de Rio Claro no ano de 2008 e buscar os fatores que se configuram como risco nas ocorrências de acidentes. Para o desenvolvimento deste trabalho foram utilizadas técnicas de geoprocesamento e estatística espacial multivariada. Uma análise local foi realizada nas áreas com maiores ocorrências de acidentes para melhor compreensão dos atributos locais. Os resultados indicam um padrão de localização de acidentes e as variáveis que contribuem para isto são grande fluxo de veículos na zona central e avenidas de trânsito rápido. O perfil dos envolvidos demonstra predominância de pessoas do sexo masculino com faixa etária entre 18 e 30 anos. Quanto ao tipo de veículos há um predomínio de carros, a seguir as motos e as bicicletas foram os mais envolvidos em acidentes. A maior parte das ocorrências aconteceu entre 9 e 18 horas, com tempo em boas condições. Estes resultados colaboram para a compreensão dos fatores que contribuem para as ocorrências de acidentes de trânsito na área urbana de Rio Claro e podem subsidiar na implantação de políticas públicas e programas nas áreas da saúde, de trânsito e segurança para a comunidade no sentido de minimizar as ocorrências e seus impactos / Abstract: Today, the traffic accidents kill more than one million people per year all over the world and injure between 20 and 50 million people. Young individuals represent the majority of the victims who, in many cases, will present sequels for the rest of their lives (DETRAN/RS, 2007). In this context, the objective of this work was to study the traffic accidents with victims in the urban area of Rio Claro in the year of 2008 and indicate the factors which represent risks for the occurrence of accidents. Geoprocessing and multivaried spatial statistic techniques were used for the development of this study. A local analysis was performed in the areas of greater incidence of accidents for a better understanding of the local attributes. The results indicate a pattern of location of accidents and the variables which contribute for this are the intense flow of vehicles in the central zone and high speed avenues. The profile of the individuals involved demonstrates predominance of males between the ages 18 to 30. Concerning the type of vehicle, cars predominate, followed by motorcycles and bicycles. Most incidents happened between 9am and 6 pm, under good weather conditions. These results help to understand the factors which contribute for the occurrence of traffic accidents in the urban area of Rio Claro and can provide subsidies for the implementation of public policies and health, traffic and safety programs for the community aiming to decrease the number of occurrences and minimize their impact / Doutorado / Epidemiologia / Doutora em Saúde Coletiva

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