Probabilistic latent semantic analysis as a potential method for integrating spatial data concepts

In this paper we explore the use of Probabilistic Latent Semantic Analysis (PLSA) as a method for quantifying semantic differences between land cover classes. The results are promising, revealing ‘hidden’ or not easily discernible data concepts. PLSA provides a ‘bottom up’ approach to interoperability problems for users in the face of ‘top down’ solutions provided by formal ontologies. We note the potential for a meta-problem of how to interpret the concepts and the need for further research to reconcile the top-down and bottom-up approaches

Exploring scientific collaborations in geographical information science (GIScience): A study of its co-authorship networks

Geographic Information Science (GIScience) as a discipline focuses on fundamental issues surrounding Geographic Information (Gl) and developments and applications of Geographical Information Technologies (GITechnologies). GIScience has accumulated a body of knowledge that can be easily exported and applied to other disciplines and assembled a wider multidisciplinary research community. Co-authorship networks are used to explore GIScience scientific collaborations during 1992-2002. Six different co-authorship networks were built from publication outlets comprising different sets of core and peripheral journals. The closer the periphery to the core, the more relevant the selected journals are to GIScience. Topological characteristics of all networks show similar networks despite the differences in sizes and the nature of the topics covered. However, networks with the peripheral journals closer to the core were more centralized around well-known scholars within the discipline. Furthermore, the network structures show a GIScience core linked to allied disciplines, especially to a highly clustered remote sensing research community. The core co-authorship network was geo-referenced using authors’ affiliation information. The results show that geographical proximity, language and cultural preferences play important roles. Countries known for their strong publishing patterns in other sciences such as England, USA and Canada were alos identified within GIScience domain. A growth of international collaboration among Scandinavian and European Countries was revealed. Results also show that China, India and Brazil have been increasing their international participation within the GIScience research community

Geovisual analytics for spatial decision support: Setting the research agenda

This article summarizes the results of the workshop on Visualization, Analytics & Spatial Decision Support, which took place at the GIScience conference in September 2006. The discussions at the workshop and analysis of the state of the art have revealed a need in concerted cross‐disciplinary efforts to achieve substantial progress in supporting space‐related decision making. The size and complexity of real‐life problems together with their ill‐defined nature call for a true synergy between the power of computational techniques and the human capabilities to analyze, envision, reason, and deliberate. Existing methods and tools are yet far from enabling this synergy. Appropriate methods can only appear as a result of a focused research based on the achievements in the fields of geovisualization and information visualization, human‐computer interaction, geographic information science, operations research, data mining and machine learning, decision science, cognitive science, and other disciplines. The name ‘Geovisual Analytics for Spatial Decision Support’ suggested for this new research direction emphasizes the importance of visualization and interactive visual interfaces and the link with the emerging research discipline of Visual Analytics. This article, as well as the whole special issue, is meant to attract the attention of scientists with relevant expertise and interests to the major challenges requiring multidisciplinary efforts and to promote the establishment of a dedicated research community where an appropriate range of competences is combined with an appropriate breadth of thinking

Exploring Uncertainty in Geodemographics with Interactive Graphics

Geodemographic classifiers characterise populations by categorising geographical areas according to the demographic and lifestyle characteristics of those who live within them. The dimension-reducing quality of such classifiers provides a simple and effective means of characterising population through a manageable set of categories, but inevitably hides heterogeneity, which varies within and between the demographic categories and geographical areas, sometimes systematically. This may have implications for their use, which is widespread in government and commerce for planning, marketing and related activities. We use novel interactive graphics to delve into OAC – a free and open geodemographic classifier that classifies the UK population in over 200,000 small geographical areas into 7 super-groups, 21 groups and 52 sub-groups. Our graphics provide access to the original 41 demographic variables used in the classification and the uncertainty associated with the classification of each geographical area on-demand. It also supports comparison geographically and by category. This serves the dual purpose of helping understand the classifier itself leading to its more informed use and providing a more comprehensive view of population in a comprehensible manner. We assess the impact of these interactive graphics on experienced OAC users who explored the details of the classification, its uncertainty and the nature of between – and within – class variation and then reflect on their experiences. Visualization of the complexities and subtleties of the classification proved to be a thought-provoking exercise both confirming and challenging users’ understanding of population, the OAC classifier and the way it is used in their organisations. Users identified three contexts for which the techniques were deemed useful in the context of local government, confirming the validity of the proposed methods

A Data-driven, High-performance and Intelligent CyberInfrastructure to Advance Spatial Sciences

abstract: In the field of Geographic Information Science (GIScience), we have witnessed the unprecedented data deluge brought about by the rapid advancement of high-resolution data observing technologies. For example, with the advancement of Earth Observation (EO) technologies, a massive amount of EO data including remote sensing data and other sensor observation data about earthquake, climate, ocean, hydrology, volcano, glacier, etc., are being collected on a daily basis by a wide range of organizations. In addition to the observation data, human-generated data including microblogs, photos, consumption records, evaluations, unstructured webpages and other Volunteered Geographical Information (VGI) are incessantly generated and shared on the Internet. Meanwhile, the emerging cyberinfrastructure rapidly increases our capacity for handling such massive data with regard to data collection and management, data integration and interoperability, data transmission and visualization, high-performance computing, etc. Cyberinfrastructure (CI) consists of computing systems, data storage systems, advanced instruments and data repositories, visualization environments, and people, all linked together by software and high-performance networks to improve research productivity and enable breakthroughs that are not otherwise possible. The Geospatial CI (GCI, or CyberGIS), as the synthesis of CI and GIScience has inherent advantages in enabling computationally intensive spatial analysis and modeling (SAM) and collaborative geospatial problem solving and decision making. This dissertation is dedicated to addressing several critical issues and improving the performance of existing methodologies and systems in the field of CyberGIS. My dissertation will include three parts: The first part is focused on developing methodologies to help public researchers find appropriate open geo-spatial datasets from millions of records provided by thousands of organizations scattered around the world efficiently and effectively. Machine learning and semantic search methods will be utilized in this research. The second part develops an interoperable and replicable geoprocessing service by synthesizing the high-performance computing (HPC) environment, the core spatial statistic/analysis algorithms from the widely adopted open source python package – Python Spatial Analysis Library (PySAL), and rich datasets acquired from the first research. The third part is dedicated to studying optimization strategies for feature data transmission and visualization. This study is intended for solving the performance issue in large feature data transmission through the Internet and visualization on the client (browser) side. Taken together, the three parts constitute an endeavor towards the methodological improvement and implementation practice of the data-driven, high-performance and intelligent CI to advance spatial sciences.Dissertation/ThesisDoctoral Dissertation Geography 201

Geospatial database generation from digital newspapers: use case for risk and disaster domains.

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies.The generation of geospatial databases is expensive in terms of time and money. Many geospatial users still lack spatial data. Geographic Information Extraction and Retrieval systems can alleviate this problem. This work proposes a method to populate spatial databases automatically from the Web. It applies the approach to the risk and disaster domain taking digital newspapers as a data source. News stories on digital newspapers contain rich thematic information that can be attached to places. The use case of automating spatial database generation is applied to Mexico using placenames. In Mexico, small and medium disasters occur most years. The facts about these are frequently mentioned in newspapers but rarely stored as records in national databases. Therefore, it is difficult to estimate human and material losses of those events. This work present two ways to extract information from digital news using natural languages techniques for distilling the text, and the national gazetteer codes to achieve placename-attribute disambiguation. Two outputs are presented; a general one that exposes highly relevant news, and another that attaches attributes of interest to placenames. The later achieved a 75% rate of thematic relevance under qualitative analysis

A 10 Years Review and Classification of the Geographic Information Systems Impact Literature (1998-2008)

Our objective in this paper is to review the literature on the impact of geographic information systems (GIS) in governmental and non-governmental organizations by analyzing 53 articles published between 1998 and 2008. The impacts of GIS are categorized in a taxonomy which designates GIS contributions to efficiency, effectiveness and societal well-being. According to this taxonomy, 38 articles are examined in-depth and their results reported. The focus of GIS impact research efforts in terms of research philosophies, methodologies and geographic focus is also presented. We suggest that the appropriate use of theories, concepts and testing of existing GIS evaluation frameworks could serve as building blocks for more rigorous studies on the impact of GIS, including Land Information Systems (LIS) and Spatial Data Infrastructure (SDI)

Road distance and travel time for spatial urban modelling

Interactions within and between urban environments include the price of houses, the flow of traffic and the intensity of noise pollution, which can all be restricted by various physical, regulatory and customary barriers. Examples of such restrictions include buildings, one-way systems and pedestrian crossings. These constrictive features create challenges for predictive modelling in urban space, which are not fully captured when proximity-based models rely on the typically used Euclidean (straight line) distance metric. Over the course of this thesis, I ask three key questions in an attempt to identify how to improve spatial models in restricted urban areas. These are: (1) which distance function best models real world spatial interactions in an urban setting? (2) when, if ever, are non-Euclidean distance functions valid for urban spatial models? and (3) what is the best way to estimate the generalisation performance of urban models utilising spatial data? This thesis answers each of these questions through three contributions supporting the interdisciplinary domain of Urban Sciences. These contributions are: (1) the provision of an improved approximation of road distance and travel time networks to model urban spatial interactions; (2) the approximation of valid distance metrics from non-Euclidean inputs for improved spatial predictions and (3) the presentation of a road distance and travel time cross-validation metric to improve the estimation of urban model generalisation. Each of these contributions provide improvements against the current state-of-the-art. Throughout, all experiments utilise real world datasets in England and Wales, such datasets contain information on restricted roads, travel times, house sales and traffic counts. With these datasets, I display a number of case studies which show up to a 32% improved model accuracy against Euclidean distances and in some cases, a 90% improvement for the estimation of model generalisation performance. Combined, the contributions improve the way that proximity-based urban models perform and also provides a more accurate estimate of generalisation performance for predictive models in urban space. The main implication of these contributions to Urban Science is the ability to better model the challenges within a city based on how they interact with themselves and each other using an improved function of urban mobility, compared with the current state-of-the-art. Such challenges may include selecting the optimal locations for emergency services, identifying the causes of traffic incidents or estimating the density of air pollution. Additionally, the key implication of this research on geostatistics is that it provides the motivation and means of undertaking non-Euclidean based research for non-urban applications, for example predicting with alternative, non-road based, mobility patterns such as migrating animals, rivers and coast lines. Finally, the implication of my research to the real estate industry is significant, in which one can now improve the accuracy of the industry's state-of-the-art nationwide house price predictor, whilst also being able to more appropriately present their accuracy estimates for robustness

Development and Assessment of a Spatial Decision Support System for Conservation Planning

Land conservation is frequently cited as the most effective means of limiting the detrimental effects of anthropogenic forces on natural resources. Because governmental entities can be hampered by fiscal and political concerns, land trusts are increasing relied on to protect habitat. However, these groups often lack the analysis and research tools necessary to meet their mission. Geographic Information System (GIs) technologies such as Spatial Decision Support Systems (SDSS) offer the promise of allowing decision makers to explore their decision space at a landscape level of analysis. But critics have charged that research in this arena is largely anecdotal in nature. This research explores the validity of this contention and presents two applied empirical studies of user satisfaction with an SDSS. In order to assess the overall maturity of the GIs discipline, articles in four journals from 1996 to 2001 were analyzed based on the scientific rigor of the research strategies employed. The results showed that, while there was an increase in the breadth of methodologies employed, the majority of studies employed qualitative ( hypothesis generating ) rather than empirical ( hypothesis testing ) designs. The findings showed need for scientifically rigorous studies in applied settings. An operational SDSS was designed that identified and prioritized suitable land parcels for protection given multiple criteria and user values. The SDSS was customized for a single land trust in Maine and four theories of user acceptance of technology were tested using a modification of the traditional case study methodology. The Relative Advantage theory provided the best explanation for user acceptance of the technology. The research design also overcame the hurdles to conducting case study research in an empirical manner. In the next stage of research, the SDSS was distributed to eighty-one land trusts for testing. An analysis of the twenty-four returned surveys indicated strong support for the User Competence theory. To the author\u27s knowledge, these two studies represented the first experimental SDSS research in an applied rather than laboratory setting