725 research outputs found

    Open source environment to define constraints in route planning for GIS-T

    Get PDF
    Route planning for transportation systems is strongly related to shortest path algorithms, an optimization problem extensively studied in the literature. To find the shortest path in a network one usually assigns weights to each branch to represent the difficulty of taking such branch. The weights construct a linear preference function ordering the variety of alternatives from the most to the least attractive.Postprint (published version

    A survey of qualitative spatial representations

    Get PDF
    Representation and reasoning with qualitative spatial relations is an important problem in artificial intelligence and has wide applications in the fields of geographic information system, computer vision, autonomous robot navigation, natural language understanding, spatial databases and so on. The reasons for this interest in using qualitative spatial relations include cognitive comprehensibility, efficiency and computational facility. This paper summarizes progress in qualitative spatial representation by describing key calculi representing different types of spatial relationships. The paper concludes with a discussion of current research and glimpse of future work

    Exploring multi-granular documentation strategies for the representation, discovery and use of geographic information

    Get PDF
    This thesis explores how digital representations of geography and Geographic Information (GI) may be described, and how these descriptions facilitate the use of the resources they depict. More specifically, it critically examines existing geospatial documentation practices and aims to identify opportunities for refinement therein, whether when used to signpost those data assets documented, for managing and maintaining information assets, or to assist in resource interpretation and discrimination. Documentation of GI can therefore facilitate its utilisation; it can be reasonably expected that by refining documentation practices, GI hold the potential for being better exploited. The underpinning theme connecting the individual papers of the thesis is one of multi-granular documentation. GI may be recorded at varying degrees of granularity, and yet traditional documentation efforts have predominantly focussed on a solitary level (that of the geospatial data layer). Developing documentation practices to account for other granularities permits the description of GI at different levels of detail and can further assist in realising its potential through better discovery, interpretation and use. One of the aims of the current work is to establish the merit of such multi-granular practices. Over the course of four research papers and a short research article, proprietary as well as open source software approaches are accordingly presented and provide proof-of-concept and conceptual solutions that aim to enhance GI utilisation through improved documentation practices. Presented in the context of an existing body of research, the proposed approaches focus on the technological infrastructure supporting data discovery, the automation of documentation processes and the implications of describing geospatial information resources of varying granularity. Each paper successively contributes to the notion that geospatial resources are potentially better exploited when documentation practices account for the multi-granular aspects of GI, and the varying ways in which such documentation may be used. In establishing the merit of multi-granular documentation, it is nevertheless recognised in the current work that instituting a comprehensive documentation strategy at several granularities may be unrealistic for some geospatial applications. Pragmatically, the level of effort required would be excessive, making universal adoption impractical. Considering however the ever-expanding volumes of geospatial data gathered and the demand for ways of managing and maintaining the usefulness of potentially unwieldy repositories, improved documentation practices are required. A system of hierarchical documentation, of self-documenting information, would provide for information discovery and retrieval from such expanding resource pools at multiple granularities, improve the accessibility of GI and ultimately, its utilisation

    Multimodal Content Delivery for Geo-services

    Get PDF
    This thesis describes a body of work carried out over several research projects in the area of multimodal interaction for location-based services. Research in this area has progressed from using simulated mobile environments to demonstrate the visual modality, to the ubiquitous delivery of rich media using multimodal interfaces (geo- services). To effectively deliver these services, research focused on innovative solutions to real-world problems in a number of disciplines including geo-location, mobile spatial interaction, location-based services, rich media interfaces and auditory user interfaces. My original contributions to knowledge are made in the areas of multimodal interaction underpinned by advances in geo-location technology and supported by the proliferation of mobile device technology into modern life. Accurate positioning is a known problem for location-based services, contributions in the area of mobile positioning demonstrate a hybrid positioning technology for mobile devices that uses terrestrial beacons to trilaterate position. Information overload is an active concern for location-based applications that struggle to manage large amounts of data, contributions in the area of egocentric visibility that filter data based on field-of-view demonstrate novel forms of multimodal input. One of the more pertinent characteristics of these applications is the delivery or output modality employed (auditory, visual or tactile). Further contributions in the area of multimodal content delivery are made, where multiple modalities are used to deliver information using graphical user interfaces, tactile interfaces and more notably auditory user interfaces. It is demonstrated how a combination of these interfaces can be used to synergistically deliver context sensitive rich media to users - in a responsive way - based on usage scenarios that consider the affordance of the device, the geographical position and bearing of the device and also the location of the device

    Reconciling the dissonance between Historic Preservation and Virtual Reality through a Place-based Virtual Heritage system.

    Get PDF
    This study explores a problematic disconnect associated with virtual heritage and the immersive 3D computer modeling of cultural heritage. The products of virtual heritage often fail to adhere to long-standing principles and recent international conventions associated with historic preservation, heritage recording, designation, and interpretation. By drawing upon the geographic concepts of space, landscape, and place, along with advances in Geographic Information Systems, first-person serious games, and head-mounted Virtual Reality platforms this study envisions, designs, implements, and evaluates a virtual heritage system that seeks to reconcile the dissonance between Virtual Reality and historic preservation. Finally, the dissertation examines the contributions and future directions of such a Place-based Virtual Heritage system in human geography and historic preservation planning and interpretation

    Discovery of Spatiotemporal Event Sequences

    Get PDF
    Finding frequent patterns plays a vital role in many analytics tasks such as finding itemsets, associations, correlations, and sequences. In recent decades, spatiotemporal frequent pattern mining has emerged with the main goal focused on developing data-driven analysis frameworks for understanding underlying spatial and temporal characteristics in massive datasets. In this thesis, we will focus on discovering spatiotemporal event sequences from large-scale region trajectory datasetes with event annotations. Spatiotemporal event sequences are the series of event types whose trajectory-based instances follow each other in spatiotemporal context. We introduce new data models for storing and processing evolving region trajectories, provide a novel framework for modeling spatiotemporal follow relationships, and present novel spatiotemporal event sequence mining algorithms

    Automated generation of geometrically-precise and semantically-informed virtual geographic environnements populated with spatially-reasoning agents

    Get PDF
    La GĂ©o-Simulation Multi-Agent (GSMA) est un paradigme de modĂ©lisation et de simulation de phĂ©nomĂšnes dynamiques dans une variĂ©tĂ© de domaines d'applications tels que le domaine du transport, le domaine des tĂ©lĂ©communications, le domaine environnemental, etc. La GSMA est utilisĂ©e pour Ă©tudier et analyser des phĂ©nomĂšnes qui mettent en jeu un grand nombre d'acteurs simulĂ©s (implĂ©mentĂ©s par des agents) qui Ă©voluent et interagissent avec une reprĂ©sentation explicite de l'espace qu'on appelle Environnement GĂ©ographique Virtuel (EGV). Afin de pouvoir interagir avec son environnement gĂ©ographique qui peut ĂȘtre dynamique, complexe et Ă©tendu (Ă  grande Ă©chelle), un agent doit d'abord disposer d'une reprĂ©sentation dĂ©taillĂ©e de ce dernier. Les EGV classiques se limitent gĂ©nĂ©ralement Ă  une reprĂ©sentation gĂ©omĂ©trique du monde rĂ©el laissant de cĂŽtĂ© les informations topologiques et sĂ©mantiques qui le caractĂ©risent. Ceci a pour consĂ©quence d'une part de produire des simulations multi-agents non plausibles, et, d'autre part, de rĂ©duire les capacitĂ©s de raisonnement spatial des agents situĂ©s. La planification de chemin est un exemple typique de raisonnement spatial dont un agent pourrait avoir besoin dans une GSMA. Les approches classiques de planification de chemin se limitent Ă  calculer un chemin qui lie deux positions situĂ©es dans l'espace et qui soit sans obstacle. Ces approches ne prennent pas en compte les caractĂ©ristiques de l'environnement (topologiques et sĂ©mantiques), ni celles des agents (types et capacitĂ©s). Les agents situĂ©s ne possĂšdent donc pas de moyens leur permettant d'acquĂ©rir les connaissances nĂ©cessaires sur l'environnement virtuel pour pouvoir prendre une dĂ©cision spatiale informĂ©e. Pour rĂ©pondre Ă  ces limites, nous proposons une nouvelle approche pour gĂ©nĂ©rer automatiquement des Environnements GĂ©ographiques Virtuels InformĂ©s (EGVI) en utilisant les donnĂ©es fournies par les SystĂšmes d'Information GĂ©ographique (SIG) enrichies par des informations sĂ©mantiques pour produire des GSMA prĂ©cises et plus rĂ©alistes. De plus, nous prĂ©sentons un algorithme de planification hiĂ©rarchique de chemin qui tire avantage de la description enrichie et optimisĂ©e de l'EGVI pour fournir aux agents un chemin qui tient compte Ă  la fois des caractĂ©ristiques de leur environnement virtuel et de leurs types et capacitĂ©s. Finalement, nous proposons une approche pour la gestion des connaissances sur l'environnement virtuel qui vise Ă  supporter la prise de dĂ©cision informĂ©e et le raisonnement spatial des agents situĂ©s

    Spatial and Temporal Sentiment Analysis of Twitter data

    Get PDF
    The public have used Twitter world wide for expressing opinions. This study focuses on spatio-temporal variation of georeferenced Tweets’ sentiment polarity, with a view to understanding how opinions evolve on Twitter over space and time and across communities of users. More specifically, the question this study tested is whether sentiment polarity on Twitter exhibits specific time-location patterns. The aim of the study is to investigate the spatial and temporal distribution of georeferenced Twitter sentiment polarity within the area of 1 km buffer around the Curtin Bentley campus boundary in Perth, Western Australia. Tweets posted in campus were assigned into six spatial zones and four time zones. A sentiment analysis was then conducted for each zone using the sentiment analyser tool in the Starlight Visual Information System software. The Feature Manipulation Engine was employed to convert non-spatial files into spatial and temporal feature class. The spatial and temporal distribution of Twitter sentiment polarity patterns over space and time was mapped using Geographic Information Systems (GIS). Some interesting results were identified. For example, the highest percentage of positive Tweets occurred in the social science area, while science and engineering and dormitory areas had the highest percentage of negative postings. The number of negative Tweets increases in the library and science and engineering areas as the end of the semester approaches, reaching a peak around an exam period, while the percentage of negative Tweets drops at the end of the semester in the entertainment and sport and dormitory area. This study will provide some insights into understanding students and staff ’s sentiment variation on Twitter, which could be useful for university teaching and learning management

    European Handbook of Crowdsourced Geographic Information

    Get PDF
    This book focuses on the study of the remarkable new source of geographic information that has become available in the form of user-generated content accessible over the Internet through mobile and Web applications. The exploitation, integration and application of these sources, termed volunteered geographic information (VGI) or crowdsourced geographic information (CGI), offer scientists an unprecedented opportunity to conduct research on a variety of topics at multiple scales and for diversified objectives. The Handbook is organized in five parts, addressing the fundamental questions: What motivates citizens to provide such information in the public domain, and what factors govern/predict its validity?What methods might be used to validate such information? Can VGI be framed within the larger domain of sensor networks, in which inert and static sensors are replaced or combined by intelligent and mobile humans equipped with sensing devices? What limitations are imposed on VGI by differential access to broadband Internet, mobile phones, and other communication technologies, and by concerns over privacy? How do VGI and crowdsourcing enable innovation applications to benefit human society? Chapters examine how crowdsourcing techniques and methods, and the VGI phenomenon, have motivated a multidisciplinary research community to identify both fields of applications and quality criteria depending on the use of VGI. Besides harvesting tools and storage of these data, research has paid remarkable attention to these information resources, in an age when information and participation is one of the most important drivers of development. The collection opens questions and points to new research directions in addition to the findings that each of the authors demonstrates. Despite rapid progress in VGI research, this Handbook also shows that there are technical, social, political and methodological challenges that require further studies and research

    European Handbook of Crowdsourced Geographic Information

    Get PDF
    "This book focuses on the study of the remarkable new source of geographic information that has become available in the form of user-generated content accessible over the Internet through mobile and Web applications. The exploitation, integration and application of these sources, termed volunteered geographic information (VGI) or crowdsourced geographic information (CGI), offer scientists an unprecedented opportunity to conduct research on a variety of topics at multiple scales and for diversified objectives. The Handbook is organized in five parts, addressing the fundamental questions: What motivates citizens to provide such information in the public domain, and what factors govern/predict its validity?What methods might be used to validate such information? Can VGI be framed within the larger domain of sensor networks, in which inert and static sensors are replaced or combined by intelligent and mobile humans equipped with sensing devices? What limitations are imposed on VGI by differential access to broadband Internet, mobile phones, and other communication technologies, and by concerns over privacy? How do VGI and crowdsourcing enable innovation applications to benefit human society? Chapters examine how crowdsourcing techniques and methods, and the VGI phenomenon, have motivated a multidisciplinary research community to identify both fields of applications and quality criteria depending on the use of VGI. Besides harvesting tools and storage of these data, research has paid remarkable attention to these information resources, in an age when information and participation is one of the most important drivers of development. The collection opens questions and points to new research directions in addition to the findings that each of the authors demonstrates. Despite rapid progress in VGI research, this Handbook also shows that there are technical, social, political and methodological challenges that require further studies and research.
    • 

    corecore