Data Structures and Algorithms for Geographic Information Systems: Selected Topics

Geographic Information Systems (GIS) are increasingly managing very large sets of data and hence a centralized data repository may not always provide the most scalable solution. Here we introduce a novel approach to manage spatial data by leveraging structured Peer-to-Peer (P2P) systems based on Distributed Hash Tables (DHTs). DHT algorithms provide efficient exact-match object search capabilities without requiring global indexing and as a result they are extremely scalable. Furthermore, the adoption of uniform hash functions ensures excellent load balancing. However, range queries -- which are very common with spatial data -- cannot be executed efficiently because the hash functions unfortunately destroy any existing data locality. Here we report on the design of an Adaptive Spatial Peer-to-pEer Network (ASPEN) that extends Content Addressable Networks (CAN) to preserve spatial locality information while also retaining many of the load balancing properties of DHT systems. We introduce the concept of scatter regions, which are spatial data distribution units that optimize both load balancing and spatial range query processing at the same time. We present a data object key generation function and algorithms for spatial range queries. We rigorously evaluate our technique with both synthetic and real world data sets and the results demonstrate the efficient execution of spatial range queries in the ASPEN system.

In this thesis, concepts for developing Spatial Data Infrastructures with an emphasis on visualizing 3D landscape and city models in distributed environments are discussed. Spatial Data Infrastructures are important for public authorities in order to perform tasks on a daily basis, and serve as research topic in geo-informatics. Joint initiatives at national and international level exist for harmonizing procedures and technologies. Interoperability is an important aspect in this context - as enabling technology for sharing, distributing, and connecting geospatial data and services. The Open Geospatial Consortium is the main driver for developing international standards in this sector and includes government agencies, universities and private companies in a consensus process. 
\n3D city models are becoming increasingly popular not only in desktop Virtual Reality applications but also for being used in professional purposes by public authorities. Spatial Data Infrastructures focus so far on the storage and exchange of 3D building and elevation data. For efficient streaming and visualization of spatial 3D data in distributed network environments such as the internet, concepts from the area of real time 3D Computer Graphics must be applied and combined with Geographic Information Systems (GIS). For example, scene graph data structures are commonly used for creating complex and dynamic 3D environments for computer games and Virtual Reality applications, but have not been introduced in GIS so far. 
\nIn this thesis, several aspects of how to create interoperable and service-based environments for 3D spatial data are addressed. These aspects are covered by publications in journals and conference proceedings. The introductory chapter provides a logic succession from geometrical operations for processing raw data, to data integration patterns, to system designs of single components, to service interface descriptions and workflows, and finally to an architecture of a complete distributed service network.
\nDigital Elevation Models are very important in 3D geo-visualization systems. Data structures, methods and processes are described for making them available in service based infrastructures. A specific mesh reduction method is used for generating lower levels of detail from very large point data sets. An integration technique is presented that allows the combination with 2D GIS data such as roads and land use areas. This approach allows using another optimization technique that greatly improves the usability for immersive 3D applications such as pedestrian navigation: flattening road and water surfaces. It is a geometric operation, which uses data structures and algorithms found in numerical simulation software implementing Finite Element Methods. 
\n3D Routing is presented as a typical application scenario for detailed 3D city models. Specific problems such as bridges, overpasses and multilevel networks are addressed and possible solutions described. The integration of routing capabilities in service infrastructures can be accomplished with standards of the Open Geospatial Consortium. An additional service is described for creating 3D networks and for generating 3D routes on the fly. Visualization of indoor routes requires different representation techniques.
\nAs server interface for providing access to all 3D data, the Web 3D Service has been used and further developed. Integrating and handling scene graph data is described in order to create rich virtual environments. Coordinate transformations of scene graphs are described in detail, which is an important aspect for ensuring interoperability between systems using different spatial reference systems. The Web 3D Service plays a central part in nearly all experiments that have been carried out. It does not only provide the means for interactive web-visualizations, but also for performing further analyses, accessing detailed feature information, and for automatic content discovery.
\nOpenStreetMap and other worldwide available datasets are used for developing a complete architecture demonstrating the scalability of 3D Spatial Data Infrastructures. Its suitability for creating 3D city models is analyzed, according to requirements set by international standards. A full virtual globe system has been developed based on OpenStreetMap including data processing, database storage, web streaming and a visualization client.
\nResults are discussed and compared to similar approaches within geo-informatics research, clarifying in which application scenarios and under which requirements the approaches in this thesis can be applied.
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Geographic Information System (GIS) is a technology that deals with location to support better representations and decision making. It has a long tradition in several planning areas, such as urbanism, environment, riskiness, transportation, archeology or tourism. In academics context higher education has followed that evolution. Despite of their potentialities in education, GIS technologies at the elementary and secondary have been underused. Empowering graduates to learn with GIS and to manipulate spatial data can effectively facilitate the teaching of critical thinking. Likewise it has been recognized that GIS tools can be incorporated as an interdisciplinary pedagogical tool. Nevertheless more practical examples on how GIS tools can enhance teaching and learning process, namely to promote interdisciplinary approaches. The proposed paper presents some results obtained from the project “Each thing in its place: the science in time and space”. This project results from the effort of three professors of Geography, History and Natural Sciences in the context of Didactics of World Knowledge curricular unit to enhance interdisciplinarity through Geographic Information Technologies (GIT). Implemented during the last three years this action-research project developed the research practice using GIS to create an interdisciplinary attitude in the future primary education teachers. More than teaching GIS the authors were focused on teaching with GIS to create an integrated vision where spatial data representation linked the space, the time and natural sciences. Accumulated experience reveals that those technologies can motivate students to learn and facilitating teacher’s interdisciplinary work.

Geographic information systems (GISs) are widely used for representation, management, and analysis of spatial data in many disciplines. In particular, geoscientists increasingly use these tools for data integration and management purposes in many environmental applications, ranging from water resources management to the study of global warming. Beyond these capabilities, geoscientists need to model and simulate three-dimensional (3D) dynamic fields and readily integrate those results with other relevant spatial information in order to have a better understanding of the environmental problems. However, GISs are very limited for the modeling and simulation of spatial fields, which are mostly 3D and dynamic. These limitations are mainly related to the existing GIS spatial data structures that are static and limited to 2D space. In order to overcome these limitations, we develop and implement a new kinetic 3D spatial data structure based on Delaunay tetrahedralization and a 3D Voronoi diagram to support a 3D dynamic field simulation within GISs. In this article, we describe in detail the different steps from discretization of a 3D continuous field to its numerical integration, based on an event-driven method. For validation of the proposed spatial data structure itself and its potential for the simulation of a dynamic field, two case studies are presented in the article. According to our observations, during the simulation process, the data structure is maintained and the 3D spatial information is managed adequately. Furthermore, the results obtained from both experiments are very satisfactory and are comparable with the results obtained from other existing methods for the simulation of the same dynamic field. To conclude, we discuss the current challenges related to the development of the 3D kinetic data structure itself and its adaptation to 3D dynamic field simulation and suggest some solutions for its improvement.

The most prominent problem of rapid urbanism in Harare is the development of slums and Epworth is a notable example. The quality of planning and decision making in the participatory slum upgrading initiative can be sustainably improved by well managed processes of spatial and socio-economic data collection. More so, existing approaches for slum upgrading are built on the basis of collaborative planning and thus community participation. Geographic Information Systems (GIS) tools and support systems should explicitly consider the needs of professional and non-professional stakeholders in slum upgrading process. This study aimed to develop a customized “GIS based slum upgrading system" that would empower the community to participate in the planning and decision making processes involved in slum upgrading. The study involved developing tools that could be used by lay people, to achieve the same results an expert would. To achieve this, a PostgreSQL/Postgis spatial database integrating the spatial and enumeration data component was developed as the backend with a front end developed using VB.Net. A Map Control tool was imported from Map window 4.7 for displaying and interacting with spatial data. Techniques such as buffering were incorporated in the system to allow users to check for structures within a given distance of a feature. The system also provided a tool that allowed users to select an area and calculate the number of stands that can be obtained after inputting parameters like stand size and type of road. The system provided for tools that calculate statistical values e.g. determining the population as well as the number of households in a selected area. Users could also query for socio-economic data by selecting spatial features. This provided flexibility in terms of the interaction of the users with the data. The system proved that with user oriented GIS system it is possible to develop tools that can be used by lay people especially those in slums to formalize their areas and obtain security of tenure.Keywords: Slum upgrading, Participatory GIS, Security of tenure

The development and increased use of geographic information systems (GIS) in policing has intensified the demand for public access to digital spatial information. For example, those in the academic arena require access to spatial information to augment their learning, teaching and research endeavours, while the general public need spatially related crime information related to their local area or region to inform decisions that impact upon their everyday living (for example, safety precautions, choice of residential suburb). Much of this information exists, such as the 2001 Census from Australian Bureau of Statistics (ABS, 2003), crime data available on the Queensland Police Service (QPS) website (http://www.police.qld.gov.au/), and the Atlas of Crime in Australia 2000 (AIC, 2000), yet often the information is not in a form that is easily accessible or comprehendable, requiring an understanding of and access to relatively complex commercial GIS packages. In recent years, police and researchers have worked closely together to develop publicly accessible web-based GIS applications for crime mapping, crime analysis, community mapping and information sharing (see, e.g., Police Foundation, 2001; Shyy et al., 2005; Chainey and Smith, 2006). Dragicevic (2004) highlights how web-based GIS has enhanced the open use of GIS in three main directions including: spatial data access and dissemination; spatial data exploration and geovisualization; and spatial data processing, analysis and modelling.

As Geographic Information Systems (GIS) technologies have evolved, more and more GIS applications and geospatial data are available on the web. Spatial objects in a given query range can be retrieved using spatial range query ? one of the most widely used query types in GIS and spatial databases. However, it can be challenging to retrieve these data from various web applications where access to the data is only possible through restrictive web interfaces that support certain types of queries. A typical scenario is the existence of numerous business web sites that provide their branch locations through a limited "nearest location" web interface. For example, a chain restaurant's web site such as McDonalds can be queried to find some of the closest locations of its branches to the user's home address. However, even though the site has the location data of all restaurants in, for example, the state of California, it is difficult to retrieve the entire data set efficiently due to its restrictive web interface. Considering that k-Nearest Neighbor (k-NN) search is one of the most popular web interfaces in accessing spatial data on the web, this paper investigates the problem of retrieving geospatial data from the web for a given spatial range query using only k-NN searches. Based on the classification of k-NN interfaces on the web, we propose a set of range query algorithms to completely cover the rectangular shape of the query range (completeness) while minimizing the number of k-NN searches as possible (efficiency). We evaluated the efficiency of the proposed algorithms through statistical analysis and empirical experiments using both synthetic and real data sets.

Geographic information systems (GIS) are becoming more usual due to the improved performance of computer systems. GIS applications are being developed using the three-tier software architecture traditionally used for general-purpose information systems. Even though this architecture is suitable for GIS applications, the special nature and exclusive characteristics of geographic information pose special functional requirements on the architecture in terms of conceptual and logical models, data structures, access methods, analysis techniques, or visualization procedures. In this paper, we propose a generic architecture for GIS that provides support for the special nature of geographic information and conforms with the specifications proposed by the ISO/TC 211 and the OGC. Our strategy to achieve this goal consists of two steps: (i) we analyze the special characteristics of GIS with respect to traditional information systems, (ii) and we adapt the traditional three-tier architecture for information systems to take into account the special characteristics of GIS. Finally, we have tried to apply the architecture that we propose in the development of a complete and complex real-life GIS application using commercial tools in the analysis, design and implementation. We describe this application, and we use it to describe the limitations of current commercial GIS development tools by analyzing the differences in the architecture of the resulting system with respect to our proposal.

While the use of three-dimensional (3D) geographical information system (GIS) is becoming in rapid development and being used in various fields such as urban and regional planning, disaster management and planning, mobile navigation and etc., commercial and open source GIS software packages tend to offer 3D-GIS functionalities for their products. On the basis, GIS analysis functions are to provide information with respect to geographical location and by having 3D spatial data as an input, it will give advantages in providing horizontal position information. However, to analyze moving objects (temporal) in 3D seems not an easy task and not fully supported by current GIS platform packages. Previously in two-dimensional (2D) GIS practice, main issue addressed by researchers in managing temporal spatial objects is GIS packages were designed based on hardware and software constraints whereby it should be based on the temporal spatial objects ontology. Nowadays, the trend of managing temporal 3D data is via 3D spatial simulation or animation. This approach will not in assistance for GIS users in conducting spatial queries. Without having a suitable ontology and valid topological data structure for temporal 3D data, it will cause repetitive of temporal data (redundancy) and complications in executing spatial analysis in 3D environment. Therefore this paper focuses on the ontology for managing moving 3D spatial objects (i.e. air pollution, flood). The characteristics of moving objects were reviewed thoroughly by categorizing it based on its different appearances. Moreover, existing methods in managing temporal database were addressed and discussed for its practicalities. Another important aspect in managing temporal 3D objects is the implementation of topological data structures for 3D spatial objects were reviewed. In the last section of this paper it summarized the issues and further ideas towards implementing and managing temporal 3D spatial objects in GIS based on the Geoinformation Ontology (GeO).

Abstract: This book presents a comprehensive and interdisciplinary framework for advancing spatial big data analytics by integrating distributed computing technologies with modern Geographic Information Systems (GIS). It addresses the growing complexity and scale of geospatial data characterized by high volume, velocity, and spatial-temporal heterogeneity. The core objective is to equip researchers, analysts, and practitioners with scalable methodologies that harness the combined power of the Hadoop ecosystem and ArcGIS platforms for processing, modeling, and visualizing large-scale spatial datasets. The analytical framework developed in this work builds on foundational spatial concepts—such as topology, projections, and spatial autocorrelation—and extends into advanced topics including spatial machine learning, geostatistics, real-time sensor stream analytics, and spatial-temporal modeling. Methodologies encompass the use of HDFS, MapReduce, GeoSpark, and SpatialHadoop for distributed processing, combined with ArcGIS tools for spatial modeling, scripting (ArcPy), and high-resolution visualization. Empirical case studies drawn from environmental monitoring, urban planning, disaster response, and precision agriculture illustrate end-to-end pipelines that emphasize reproducibility, ethical data handling, and decision-oriented visualization. The key contribution of this volume lies in bridging computational infrastructure with geospatial reasoning, offering a scalable, interoperable, and ethically informed approach to modern spatial data science. Keywords spatial big data, geospatial analytics, Hadoop, ArcGIS, spatial machine learning, spatial-temporal modeling, GIS, MapReduce, GeoSpark, SpatialHadoop, ArcPy, distributed computing, geostatistics, spatial data visualization, real-time stream analytics, spatial data science, geoinformatics, environmental monitoring, urban analytics, data-intensive GIS

Geographic Information Systems: A New Research Method for Book History 1 Fiona A. Black (bio), Bertrum H. MacDonald (bio), and J. Malcolm W. Black (bio) In their seminal work on book history, Lucien Febvre and Henri-Jean Martin very aptly described the early spread of printing as the “geography of the book.” 2 Their account appeared years before any means was available to relate effectively important spatial data with some or all of the other factors that book historians traditionally study. Beginning in the 1960s, however, new computer-based technology that deals with spatial data—geographic information systems (GIS)—was developed, first by government agencies, then by private industry. More recently, application of this technology has spread to the academy with increasing use by individual scholars. After three decades of development, GIS technology has evolved to a state where it can be employed to explore constructively the “geography of the book.” Although GIS technology is not yet familiar to book historians, it has been employed in an increasing number of fields since its inception and it currently forms a multi-billion-dollar industry worldwide. GIS technology has been used principally in environmental and other applied sciences and as a support for management decision-making systems. 3 This technology might have remained of little interest to those concerned with the historical spread and development of print culture, except for two relatively recent developments. First, a growing number of scholars have begun to recognize [End Page 11] that GIS can provide a powerful means of answering historical questions; and second, the increasing availability of GIS software for use with personal computers means that it is now practical for individual researchers to take advantage of the technology. 4 Book historians and bibliographers are of course no strangers to computer technologies and in this article we aim to show that GIS, with its visual and analytical capabilities, is another application so robust that it will help to uncover new information about the history of print culture. Our purpose here is to highlight potential avenues of exploration that will be of collective benefit in many aspects of book history research, and at the same time we call for contributions of databases relevant to a proposed collaborative project. Computer-based Tools for Book History Computer technologies, especially databases, have become familiar in recent decades not only for facilitating improved access to secondary literature but also for constructing primary research resources, such as the Eighteenth-Century Short Title Catalogue (ESTC). Researchers are not limited to bibliographic files, however, for there are now a number of significant nonbibliographic databases related to the history of books and readers, including book-trade indexes for a variety of cities and countries and the new Reading Experience Database. The value of these databases notwithstanding, we believe that computer technologies can be applied by book historians with much greater consequence than they have hitherto. Robert Darnton contended that Febvre and Martin’s approach to book history “demonstrated the importance of asking new questions, using new methods, and tapping new sources.” 5 It is this perspective, namely, using new methods to tap new sources in order to ask new questions and thereby arrive at new knowledge, that governs our consideration of geographic information systems for book history investigations. Historians face a wealth of data as they unravel the complexity of print culture. Numerous aspects of this culture, such as the reading experiences of an individual, are qualitative in nature and cannot be “counted” (though as the Reading Experience Database would indicate, they can still be organized into database fields for the purposes of research). Nonetheless, many other aspects can be quantified or positioned in space, for example, the number of books printed; the number of books sold; the quantities of books exported; the time from date of publication to the arrival in particular towns, cities, and countries; the location of bookstores; and literacy rates of [End Page 12] distinct populations. Indeed as historians of print culture accumulate increasing masses of quantitative data, it is becoming clear that much more can be done by way of analysis. As Michael Goodchild, director of the National Center for Geographic Information and Analysis in the United States has...

This research paper discusses about the application of Web-Based Geographical Information System (GIS), an ICT tool for electronic business; particularly through Internet, with a future plan to develop e-promotion and strategic marketing by implementing Web GIS tools for Geobusiness. In the context of e-business, this present study penetrates the usage of GIS to disseminate maximum level of information to the customers. On the other hand, it depicts the growing incorporation of GIS in target marketing, business management, and strategic decision-making processes. It discusses how this modern Geospatial Information Technology (GIT) tool is used for collecting and analyzing information for the efficient and effective management and promotion of e-commerce. Geographical Information System (GIS) is the fundamental science and technology for Geo Design, a systematic methodology of Geographic planning and decision making. Web GIS is the modern technology for capturing, storing, retrieving, mapping and analyzing spatial and non-spatial geographical data in the digital format over the internet. It provides all the GIS functions over the Web, these functions can, in turn, be applied in various sectors of e-business. This paper highlights on the technical aspects of Web GIS for strategic planning, daily business operations, supply chain management, marketing, customer service, improving efficiency and attaining competitive advantage for business organizations.

Distributed computation of the knn graph for large high-dimensional point sets

Abstract. Research in geographic information science has not yet found clear answers to the questions of what geographic information is about or what a geographic information system (GIS) contains. This lack of consensus makes it especially challenging to teach and learn GIS. Existing pedagogical approaches either focus on the representational level of data (e.g., “raster and vector”) or are too generic (e.g., “geo-referenced information”). This characterization of GIS and its content is difficult for learners to transfer and apply broadly. As instructors, we approach the challenge of teaching GIS from a conceptual basis. We describe our process to develop a set of core concepts of spatial information, which we use to redesign an undergraduate-level introductory GIS course. Our intervention focuses instruction on the kinds of questions that geographic information enables before training students to produce workflows and answers through system commands. The course redesign complements and informs ongoing research on core concepts of spatial information. Our results demonstrate that GIS courses can deliver more than software training, indicating both theoretical gains and didactic challenges.

Interaction with geographic information systems via spatial queries