Management and visualization of spatiotemporal information in GIS

Although Geographic Information Systems (GIS) have been recognised as the most advanced technology for the management of geospatial information, they are still unable to efficiently manage the temporal dimension. Originally this problem affeeted only the study and analysis of highly dynamic phenomena. Today's expansion of GIS technology, the ease to acquire and store geospatial data and the increased capacity of computing technologies to managc large amounl of data have contributed lo the propagation of this problem across the whole geospatial seclor. The extended use of GIS in decision-making processes is increasing the demand for tools able to manage and 10 analyse dynamic geospatial phenomena where the temporal dimension is crucial. The only temporal model available in commercial GIS packages is based on discretisation of temporal data. Changes are represented as a succession of snapshots. The dynamics and what happens between those stages are not registered. In addition, this approach presents severe problems due to unavoidable multiplication of data volume, abundant redundancies, loss in query efficiency and the impossibility of knowing when the exact timing of changes occurs. Since the late 1980s and particularly in the 1990s, researching the temporal changes and the conceptual and technological options available has been undertaken by the GIS and DBMS sectors. The primary objective of the research presented in this paper is the development of a model for the integration of temporal data with GIS. The method adopted to achieve this objective is based on the combination of Time Geography principies, its graphic language and dynamic segmentation techniques used in GIS. Past research has demonstrated that the difficulty to integrate time with GIS has its origin in the continuous nature of time. Dynamic segmentation in GIS network analysis has the potential to provide the means for a time-GIS integration in a continuous manner. Lifelines, one of the main Time geography's graphic language elements, has been modelled as a set of network segments where the dynamics in attribute information has been attached to different time segments rather than distance segments (for exampIe Euclidean or cost-based) as normally occurs in dynamic segmentation. This paper summarises initial findings of the project. These outcomes have the potential to improve the way the geospatial sector currently handles temporal information. However, the static nature of current GIS technology impedes an appropriate visualisation of dynamic temporal phenomena. To this effect, the paper also explores the possibilities offered by multimedia techniques as a complement to GIS capabilities

Tratamento de versões em bancos de dados para sistema de informações geograficas

Orientador: Claudia M. Bauzer MedeirosDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Sistemas de Informação têm introduzido modelos e mecanismos de versões para a manutenção de múltiplos estados ou variações das entidades modeladas. As aplicações fundamentais de versões estão associadas à manutenção de alternativas de projetos em sistemas CAD / CASE e na representação histórica de entidades em sistemas temporais. Esta dissertação apresenta um estudo sobre as aplicações de versões em SIG enfatizando aspectos relativos a aplicações temporais, manipulação de múltiplas representações para as entidades espaciais modeladas e facilidades para manutenção de alternativas de projeto espacial. Os principais resultados são: a proposta de um modelo e mecanismo de versões com recursos básicos para dar apoio a estas aplicações; e uma proposta de extensão a um SGBDOO padrão para permitir a inclusão dos recursos do modeloAbstract: Information systems contemplate version models and mechanisms for the management of multiple states of modeled entities. Versions are associated, mainly, to the management of alternatives in CAD /CASE systems and the representation of historical evolution of entities in temporal systems. This dissertation studies the use of versions in Geographic 1nformation Systems (GIS). The focus of this work is on temporal applications, multiple representations of spatial entities, and the management of alternatives of spatial design. The main results presented are: a model and a mechanism for versions in order to support geographic applications; and the proposal of an extension to a standard OODBMS to support the modelMestradoMestre em Ciência da Computaçã

Um banco de dados espaço-temporal para desenvolvimento de aplicações em sistemas de informação geografica

Orientadores: Claudia M. Bauzer Medeiros, Mario A. NascimentoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Esta dissertação discute a implementação de uma infra-estrutura extensível, baseada em um sistema gerenciador de banco de dados orientado a objetos, que provê suporte ao desenvolvimento de aplicações espaço-temporais. A infra-estrutura está baseada na definição e implementação de um conjunto básico de operadores e classes orientadas a objetos, que cobrem os requisitos mínimos de processamento de consultas espaciais, temporais e espaço- temporais. As principais contribuições deste trabalho são a definição dos operadores e das classes e sua implementação efetiva, validada através de uma aplicação piloto. Uma contribuição adicional é a discussão da própria implementação, que permitiu corrigir falhas do modelo teórico adotado.Abstract: This dissertation discusses the implementation of an extensible framework, which provides support for the development of spatio-temporal database applications. The infrastructure, developed on the O2 object-oriented database system, consists of a kernel set of operators and database classes, which meet the minimum requirements for the processing of spatial, temporal and spatio-temporal queries. The main contributions of this work are the specification of the kernel operators and classes and their implementation, validated through a pilot geographic application. Another contribution is fhe analysis of this implementation, which discusses problems and shortcomings of some models proposed in the literature.MestradoMestre em Ciência da Computaçã

Analysis and Geovisualisation of Hector’s Dolphin Abundance and Distribution Patterns in Space and Time

While Hector’s dolphin (Cephalorhynchus hectorii) has been the topic of many research projects within the first Marine Mammal Sanctuary in New Zealand, few long-term analytical abundance and distribution projects in other population strongholds have been conducted. The primary purpose of this thesis project was to test quantitative observations that suggested that this unprotected population of Hector’s dolphin at Te Waewae Bay, on the south coast of the South Island, New Zealand, may be in decline and utilises non-continuous portions of the coastline. Seasonal patterns of distribution and density were extracted from a rich data set collected over 24 consecutive months that provided fine-scale data of encounters with dolphins along four preplanned transects that followed the concave nature of the bay. Monthly data were binned into seasons producing eight seasons of data over the two years. Survey results revealed that Hector’s dolphin in warmer seasons were found in greater densities closer to shore and that in the cooler seasons the range extended outward and across more offshore areas. Individual seasons did not have as strong a pattern as the complete two year data set that indicated hotspots of higher densities of dolphins in the vicinity of freshwater inputs into Te Waewae Bay. To explore individual spatio-temporal movement patterns and how the individual patterns relate to group spatio-temporal patterns, 58 individual Hector’s dolphin movements were extracted from geo-tagged photographic data and then analysed. Visual analysis of movement patterns of individual dolphins were found to vary dramatically, having distribution patterns that exhibited a high degree of site fidelity. Most notable were the twenty one dolphins that remained in relatively small areas on either the east (ten dolphins) or west (eleven dolphins) halves of the bay. This evidence of strong site fidelity may suggest partitioning along as yet unidentified social or environmental parameters. Abundance estimates were calculated from mark-recapture photographic identifications. Calculations using Pollock’s Robust Design were limited to seasonal estimates of the total population of Hector’s dolphins, which ranged from the low in winter 2005 of 380 (CV=13%; 95% CI, 300-500) to the high in summer 2005/2006 of 580 (CV=9%; 95% CI, 480-700). The estimates from these eight seasons correspond to the numbers of dolphins that utilise the bay as their primary homerange and indicate that the population is not yet in a critical decline. However, caution is urged in interpretation because two years of field data is insufficient to calculate robust survival or reproduction rates for such a long lived species. To examine whether statistically quantifiable relationships exist between environmental variables and dolphin distribution patterns, both global (ordinary least squares; OLS) and local regression (geographically weighted regression; GWR) modelling techniques were applied. The local model was a spatially explicit model. The GWR model outperformed the OLS model, revealing statistically significant hotspots directly related to the amount of rain falling four days prior to the surveys being conducted as well as to distance from the main source of freshwater in the bay. The outcomes from this thesis offer a robust baseline of information regarding the population of Hector’s dolphin in Te Waewae Bay, such that management will have the capacity to monitor long term changes in abundance and distribution. This thesis findings have suggested that freshwater input may play a crucial role in Hector’s dolphin distribution in Te Waewae Bay, which when added to previous research results indicating the importance of oceanic frontal zones, water clarity, and depth, suggests that the picture of habitat requirements for Hector’s dolphin is becoming less obscure

Géomatique et géographie de l'environnement. De l'analyse spatiale à la modélisation prospective

Le présent mémoire retrace notre parcours géomatique de géographe de l'environnement, en le situant d'abord dans le champ scientifique avant de résumer les principales approches en modélisation et en simulation prospective applicables dans ce domaine. Sur ces bases, nous présentons le modèle géomatique de simulation prospective de l'occupation du sol que nous avons établi, avant de conclure en ouvrant des perspectives de recherches. Dans la première partie, le positionnement scientifique de la géomatique fait l'objet des 2 premiers chapitres qui analysent l'émergence de ce nouveau champ transdisciplinaire et ses relations avec la géographie. La seconde partie est consacrée à la modélisation et à la simulation prospective de dynamiques environnementales. Dans une dernière partie, plus brève, nous concluons ce mémoire en esquissant quelques perspectives. Perspectives de développement des recherches en matière de modélisation d'abord, mais aussi de thématiques environnementales que nous souhaitons approfondir. Enfin sont suggérées quelques pistes sur la valorisation de nos recherches et les nouveaux enjeux de la formation géomatique en géographie. Un second fascicule complète le premier et fait état, outre le curriculum vitae, de nos activités professionnelles et publications

Design and Implementation of a Multi-Purpose Object-Orientated Spatio-Temporal (MPooST) Data Model for Cadastral and Land Information Systems (C/LIS)

The application of the object-oriented methodology in geospatial information management has significantly increased during the last 10 years and tends to gradually replace the status quo relational technology. In general, object orientation offers a flexible and adaptable modelling framework to satisfy the most demanding complex data structuring requirements. The objective of this thesis is to determine how a modern Land Information System used for cadastral purposes can benefit from an object-oriented methodology. To this aim, a Multi-Purpose, Object-Oriented Spatio-Temporal (abbreviated as MPOOST) data model has been developed. In brief, the MPOOST data model embodies spatial data and their temporal reference in the form of objects which contain their attributes as well as their behaviour. The design of the MPOOST data model has been specified in such a way that it enables other data models to exploit its functionality, therefore enabling the multi-purpose aspect. At first, the requirements of Land Information Systems are being examined. Next, the functionality that is offered by the object-oriented methodology is being analysed in detail. Even if the bibliography is quite rich in relevant research, however there seems to be no starting point regarding the application of OO in LIS. Hence, a whole chapter of this thesis has been dedicated in an extended bibliographic research. Finally, the OO methodology is applied for the design and implementation of the MPOOST data model. The outcome of the design and the implementation is the first version of the MPOOST data model written using the Java object-oriented programming language. In this way, it is proven that: the relational technology has significant drawbacks which prohibit it from being applied in conceptually demanding information systems; and that object-orientation can fully satisfy the most complex data structuring requirements posed in modern geographic information systems

Development and implementation of models and methods in temporal GIS for spatial network planning decision support

Geographical Information Systems (GIS) are today widely used for management of spatial data, particularly that relating to network infrastructure for telecommunications, utilities and transport. GIS also form a valuable tool for planning the future development of such networks and many organisations use GIS packages for this, despite the fact that it is not necessarily a task for which they have been designed. They may therefore lack many features that are of benefit, or even essential, for efficient storage and analysis of data relating to future designs. This thesis considers what the characteristics of such data may be and what shortcomings exist in current GIS regarding this, and then describes the development, implementation and testing of suitable models and methods to address these shortcomings. Of particular importance is found to be the need for a network-planning GIS application to incorporate an appropriate model of time for handling situations where there may be many alternative scenarios, a subject which has hitherto been largely unaddressed by GIS research despite having obvious applications. Existing temporal models are therefore examined to find the most suitable, which is then developed from a broad conceptual model to a model specifically designed for application to spatial network planning; Temporal Topology. The possibility for automated design optimisation using this model is then introduced, and some appropriate methods for performing this task are given. Issues which may affect the implementation of an application using the Temporal Topology model and these optimisation methods are then considered before the description of an implementation which was used to carry out a network planning case study with the aim of testing the concepts developed in this thesis. The implications of this research on the wider field of GIS, and particularly Temporal GIS are then considered.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Effects of scale and spatial variability on hydraulic geometry in the Potomac River Basin

Scale issues in hydrology arise because different hydrological processes are dominant at different regional scales. Recent hydrological research suggests that the geographic scale (size) of watersheds may influence the behavior of hydraulic geometry exponents (b and f, but not m values) of stream channels. Hence, the working hypothesis of this study is that variations of hydraulic geometry exponents are not random, but that there are systematic changes as a function of geographic scale as well as of water basin and channel physical and environmental characteristics (predictor variables). To support this analysis, 43 subbasins in the Potomac River Basin ranging in size from 0.38 square miles to 1,642 square miles and representing a broad spatial diversity of predictor variables within the watershed were selected for study. Research goals were to attempt, via empirical correlations, to discern relationships between a geographic scale factor and b, f, and m values, to investigate the roles of predictor variables on b, f, and m values, and their statistical significance, and to identify the most influential predictor variables and the complexity of fluvial physical processes via stepwise multi-variable regressions. Statistical evidence was found that there is a relationship between geographic scale and hydraulic geometry exponents. In every selected predictor variable case, investigation of the correlations between b, f, and m with a single selected predictor variable in a scale context resulted in a noticeable improvement over the correlations of the hydraulic exponents with each individual predictor variable alone. The research shows that, under higher discharges, the behavior of b, f, and m mainly result in higher m and f, with a slight increase in cross-sectional area (f with negative b) in a scale context