42,106 research outputs found

    Geospatial information infrastructures

    Get PDF
    Manual of Digital Earth / Editors: Huadong Guo, Michael F. Goodchild, Alessandro Annoni .- Springer, 2020 .- ISBN: 978-981-32-9915-3Geospatial information infrastructures (GIIs) provide the technological, semantic,organizationalandlegalstructurethatallowforthediscovery,sharing,and use of geospatial information (GI). In this chapter, we introduce the overall concept and surrounding notions such as geographic information systems (GIS) and spatial datainfrastructures(SDI).WeoutlinethehistoryofGIIsintermsoftheorganizational andtechnologicaldevelopmentsaswellasthecurrentstate-of-art,andreïŹ‚ectonsome of the central challenges and possible future trajectories. We focus on the tension betweenincreasedneedsforstandardizationandtheever-acceleratingtechnological changes. We conclude that GIIs evolved as a strong underpinning contribution to implementation of the Digital Earth vision. In the future, these infrastructures are challengedtobecomeïŹ‚exibleandrobustenoughtoabsorbandembracetechnological transformationsandtheaccompanyingsocietalandorganizationalimplications.With this contribution, we present the reader a comprehensive overview of the ïŹeld and a solid basis for reïŹ‚ections about future developments

    From Sensor to Observation Web with Environmental Enablers in the Future Internet

    Get PDF
    This paper outlines the grand challenges in global sustainability research and the objectives of the FP7 Future Internet PPP program within the Digital Agenda for Europe. Large user communities are generating significant amounts of valuable environmental observations at local and regional scales using the devices and services of the Future Internet. These communities’ environmental observations represent a wealth of information which is currently hardly used or used only in isolation and therefore in need of integration with other information sources. Indeed, this very integration will lead to a paradigm shift from a mere Sensor Web to an Observation Web with semantically enriched content emanating from sensors, environmental simulations and citizens. The paper also describes the research challenges to realize the Observation Web and the associated environmental enablers for the Future Internet. Such an environmental enabler could for instance be an electronic sensing device, a web-service application, or even a social networking group affording or facilitating the capability of the Future Internet applications to consume, produce, and use environmental observations in cross-domain applications. The term ?envirofied? Future Internet is coined to describe this overall target that forms a cornerstone of work in the Environmental Usage Area within the Future Internet PPP program. Relevant trends described in the paper are the usage of ubiquitous sensors (anywhere), the provision and generation of information by citizens, and the convergence of real and virtual realities to convey understanding of environmental observations. The paper addresses the technical challenges in the Environmental Usage Area and the need for designing multi-style service oriented architecture. Key topics are the mapping of requirements to capabilities, providing scalability and robustness with implementing context aware information retrieval. Another essential research topic is handling data fusion and model based computation, and the related propagation of information uncertainty. Approaches to security, standardization and harmonization, all essential for sustainable solutions, are summarized from the perspective of the Environmental Usage Area. The paper concludes with an overview of emerging, high impact applications in the environmental areas concerning land ecosystems (biodiversity), air quality (atmospheric conditions) and water ecosystems (marine asset management)

    Implementation and assessment of two density-based outlier detection methods over large spatial point clouds

    Get PDF
    Several technologies provide datasets consisting of a large number of spatial points, commonly referred to as point-clouds. These point datasets provide spatial information regarding the phenomenon that is to be investigated, adding value through knowledge of forms and spatial relationships. Accurate methods for automatic outlier detection is a key step. In this note we use a completely open-source workflow to assess two outlier detection methods, statistical outlier removal (SOR) filter and local outlier factor (LOF) filter. The latter was implemented ex-novo for this work using the Point Cloud Library (PCL) environment. Source code is available in a GitHub repository for inclusion in PCL builds. Two very different spatial point datasets are used for accuracy assessment. One is obtained from dense image matching of a photogrammetric survey (SfM) and the other from floating car data (FCD) coming from a smart-city mobility framework providing a position every second of two public transportation bus tracks. Outliers were simulated in the SfM dataset, and manually detected and selected in the FCD dataset. Simulation in SfM was carried out in order to create a controlled set with two classes of outliers: clustered points (up to 30 points per cluster) and isolated points, in both cases at random distances from the other points. Optimal number of nearest neighbours (KNN) and optimal thresholds of SOR and LOF values were defined using area under the curve (AUC) of the receiver operating characteristic (ROC) curve. Absolute differences from median values of LOF and SOR (defined as LOF2 and SOR2) were also tested as metrics for detecting outliers, and optimal thresholds defined through AUC of ROC curves. Results show a strong dependency on the point distribution in the dataset and in the local density fluctuations. In SfM dataset the LOF2 and SOR2 methods performed best, with an optimal KNN value of 60; LOF2 approach gave a slightly better result if considering clustered outliers (true positive rate: LOF2\u2009=\u200959.7% SOR2\u2009=\u200953%). For FCD, SOR with low KNN values performed better for one of the two bus tracks, and LOF with high KNN values for the other; these differences are due to very different local point density. We conclude that choice of outlier detection algorithm very much depends on characteristic of the dataset\u2019s point distribution, no one-solution-fits-all. Conclusions provide some information of what characteristics of the datasets can help to choose the optimal method and KNN values

    Internet of things

    Get PDF
    Manual of Digital Earth / Editors: Huadong Guo, Michael F. Goodchild, Alessandro Annoni .- Springer, 2020 .- ISBN: 978-981-32-9915-3Digital Earth was born with the aim of replicating the real world within the digital world. Many efforts have been made to observe and sense the Earth, both from space (remote sensing) and by using in situ sensors. Focusing on the latter, advances in Digital Earth have established vital bridges to exploit these sensors and their networks by taking location as a key element. The current era of connectivity envisions that everything is connected to everything. The concept of the Internet of Things(IoT)emergedasaholisticproposaltoenableanecosystemofvaried,heterogeneous networked objects and devices to speak to and interact with each other. To make the IoT ecosystem a reality, it is necessary to understand the electronic components, communication protocols, real-time analysis techniques, and the location of the objects and devices. The IoT ecosystem and the Digital Earth (DE) jointly form interrelated infrastructures for addressing today’s pressing issues and complex challenges. In this chapter, we explore the synergies and frictions in establishing an efïŹcient and permanent collaboration between the two infrastructures, in order to adequately address multidisciplinary and increasingly complex real-world problems. Although there are still some pending issues, the identiïŹed synergies generate optimism for a true collaboration between the Internet of Things and the Digital Earth

    Seafloor characterization using airborne hyperspectral co-registration procedures independent from attitude and positioning sensors

    Get PDF
    The advance of remote-sensing technology and data-storage capabilities has progressed in the last decade to commercial multi-sensor data collection. There is a constant need to characterize, quantify and monitor the coastal areas for habitat research and coastal management. In this paper, we present work on seafloor characterization that uses hyperspectral imagery (HSI). The HSI data allows the operator to extend seafloor characterization from multibeam backscatter towards land and thus creates a seamless ocean-to-land characterization of the littoral zone

    Global-Scale Resource Survey and Performance Monitoring of Public OGC Web Map Services

    Full text link
    One of the most widely-implemented service standards provided by the Open Geospatial Consortium (OGC) to the user community is the Web Map Service (WMS). WMS is widely employed globally, but there is limited knowledge of the global distribution, adoption status or the service quality of these online WMS resources. To fill this void, we investigated global WMSs resources and performed distributed performance monitoring of these services. This paper explicates a distributed monitoring framework that was used to monitor 46,296 WMSs continuously for over one year and a crawling method to discover these WMSs. We analyzed server locations, provider types, themes, the spatiotemporal coverage of map layers and the service versions for 41,703 valid WMSs. Furthermore, we appraised the stability and performance of basic operations for 1210 selected WMSs (i.e., GetCapabilities and GetMap). We discuss the major reasons for request errors and performance issues, as well as the relationship between service response times and the spatiotemporal distribution of client monitoring sites. This paper will help service providers, end users and developers of standards to grasp the status of global WMS resources, as well as to understand the adoption status of OGC standards. The conclusions drawn in this paper can benefit geospatial resource discovery, service performance evaluation and guide service performance improvements.Comment: 24 pages; 15 figure

    Developing Data Extraction and Dynamic Data Visualization (Styling) Modules for Web GIS Risk Assessment System (WGRAS)

    Get PDF
    Interactive web-GIS tools play an important role in determining disaster risk assessment which ultimately result in reduction of unexpected damages, cost and saves millions of lives. Disaster management practitioners largely benefited information at their disposal about location where possible incidents are eminent, anticipate the impact and project possible outcomes to help mitigate and organize proper response. It is also important to note that, accurate and timely information is critical for coherent coordination in response to disasters. All the above can be achieved through proper data collection combined with computer assisted modelling, analysis, production and timely dissemination of spatial information. This Master’s thesis aims to extend features of Web GIS for Risk Assessment (WGRAS) project conducted at the Department of Physical Geography and Ecosystem Science at Lund University. The work includes development of tools for geospatial data acquisition and extraction from freely available external open non-commercial sources and dynamic, user-oriented map Visualization allowing user-defined symbolization and coloring resulting flexible visual portrayal of geospatial data in the web environment. In this regard, solutions are driven based upon open source, open data and implementation strictly complies with open web standard protocols and web services. As a result, WGRAS is furnished with easy and user driven raw geo-spatial data extracts for an area of interest from OpenStreetMap (OSM). Thus, data is automatically stored for later use for different spatial modelling and analysis. The second most important contribution of this thesis is the feature developed to solve visualization of geographic information through a map server where maps are generated with a pre-defined style that limits user’s visual needs. Visualization module enables dynamic definition of style (symbolization and coloring) data which assist non-GIS expert to produce instant and meaningful presentation of maps to the end user. Overall, the work in this practical thesis adds value to disaster management and analysis in terms of easy provision of data and enabling clear dissection of disaster prone areas using effective visualization mechanism.Interactive web-GIS tools play an important role in determining disaster risk assessment which ultimately result in reduction of unexpected damages, cost and saves millions of lives. Disaster management practitioners largely benefited information at their disposal about location where possible incidents are eminent, anticipate the impact and project possible outcomes to help mitigate and organized response. It is also important to note that, accurate and timely information is critical for coherent coordination in response to disasters. This can be achieved through proper data collection combined with computer assisted modelling, analysis, production and timely dissemination of spatial information. This Master’s thesis aims to extend features of Web GIS for Risk Assessment (WGRAS) project conducted at the Department of Physical Geography and Ecosystem Science at Lund University. Modules are developed to enable easy integration of geospatial data extraction from freely available sources which are open to use and non-commercial. Implementation is facilitated with intuitive user interface which allows extracts for an area by location name(s) or area defined by two latitude and two longitude values. The other major contribution of the study focuses on visualization of geographic information in the web environment. Currently, map servers use pre-defined styling mechanism which virtually doesn’t satisfy user’s visual needs. This module enable dynamic and user-oriented map visualization allowing non-GIS experts to define (symbolization and colouring) and produce instant and meaningful presentation of maps to the end user. As recommendation, visualization of geographic data in the web environment should further be examined, especially the map servers in use should integrate powerful and meaningful dynamic styling on top existing pre-defined style. In conclusion, this thesis adds value for disaster management and analysis in terms of easy provision of geographic data and enabling clear dissection of disaster prone areas using effective visualization mechanism

    FogGIS: Fog Computing for Geospatial Big Data Analytics

    Full text link
    Cloud Geographic Information Systems (GIS) has emerged as a tool for analysis, processing and transmission of geospatial data. The Fog computing is a paradigm where Fog devices help to increase throughput and reduce latency at the edge of the client. This paper developed a Fog-based framework named Fog GIS for mining analytics from geospatial data. We built a prototype using Intel Edison, an embedded microprocessor. We validated the FogGIS by doing preliminary analysis. including compression, and overlay analysis. Results showed that Fog computing hold a great promise for analysis of geospatial data. We used several open source compression techniques for reducing the transmission to the cloud.Comment: 6 pages, 4 figures, 1 table, 3rd IEEE Uttar Pradesh Section International Conference on Electrical, Computer and Electronics (09-11 December, 2016) Indian Institute of Technology (Banaras Hindu University) Varanasi, Indi
    • 

    corecore