Flexible Querying of Imperfect Temporal Metadata in Spatial Data Infrastructures

Author(s):  
Gloria Bordogna ◽  
Francesco Bucci ◽  
Paola Carrara ◽  
Monica Pepe ◽  
Anna Rampini

Spatial Data Infrastructures (SDI) allow users connected to the Internet to share and access remote and distributed heterogeneous geodata that are managed by their providers at their own Web sites. In SDIs, available geodata can be found via standard discovery geo-services that makes available query facilities of a metadata catalog. By expressing precise selection conditions on the values of the metadata collected in the catalog, the user can discover interesting and relevant geodata and then access them by means of the services of the SDI. An important dimension of geodata that often concerns such users’ requests is the temporal information that can have multiple semantics. Current practice to perform geodata discovery in SDIs is inadequate for several reasons. First of all, with respect to the temporal characterization, available recommendations for metadata specification, for example, the INSPIRE Directive of the European community do not consider the multiple semantics of the temporal metadata. To this aim, this chapter proposes to enrich the current temporal metadata with the possibility to indicate temporal metadata related to both the observations, i.e., the geodata, the observed event, i.e., the objects in the geodata, and the temporal resolution of observations, i.e., their timestamps. The chapter introduces also a proposal to manage temporal series of geodata observed at different dates. Moreover, in order to represent the uncertain and incomplete knowledge of the time information on the available geodata, the chapter proposes a representation for imperfect temporal metadata within the fuzzy set framework. Another issue that is faced in this chapter is the inadequacy of current discovery service query facilities: in order to obtain a list of geodata results, corresponding values of metadata must exactly match the query conditions. To allow more flexibility, the chapter proposes to adopt the framework of fuzzy databases to allow expressing soft selection conditions, i.e., tolerant to under-satisfaction, so as to retrieve geodata in decreasing order of relevance to the user needs. The chapter illustrates this proposal by an example.

2018 ◽  
Vol 7 (10) ◽  
pp. 385 ◽  
Author(s):  
Matthes Rieke ◽  
Lorenzo Bigagli ◽  
Stefan Herle ◽  
Simon Jirka ◽  
Alexander Kotsev ◽  
...  

The nature of contemporary spatial data infrastructures lies in the provision of geospatial information in an on-demand fashion. Although recent applications identified the need to react to real-time information in a time-critical way, research efforts in the field of geospatial Internet of Things in particular have identified substantial gaps in this context, ranging from a lack of standardisation for event-based architectures to the meaningful handling of real-time information as “events”. This manuscript presents work in the field of event-driven architectures as part of spatial data infrastructures with a particular focus on sensor networks and the devices capturing in-situ measurements. The current landscape of spatial data infrastructures is outlined and used as the basis for identifying existing gaps that retain certain geospatial applications from using real-time information. We present a selection of approaches—developed in different research projects—to overcome these gaps. Being designed for specific application domains, these approaches share commonalities as well as orthogonal solutions and can build the foundation of an overall event-driven spatial data infrastructure.


Author(s):  
Matthes Rieke ◽  
Lorenzo Bigagli ◽  
Stefan Herle ◽  
Simon Jirka ◽  
Alexander Kotsev ◽  
...  

The nature of contemporary Spatial Data Infrastructures lies in the provision of geospatial information in an on-demand fashion. Though recent applications identified the need to react to real-time information in a time-critical way. In particular, research efforts in the field of geospatial Internet of Things have identified substantial gaps in this context, ranging from a lack of standardization for event-based architectures to the meaningful handling of real-time information as ''events''. This manuscript presents work in the field of Event-driven Spatial Data Infrastructures with a particular focus on sensor networks and the devices capturing in-situ measurements. The current landscape of Spatial Data Infrastructures is outlined and used as the basis for identifying existing gaps that retain certain geospatial applications from using real-time information. We present a selection of approaches - developed in different research projects - to overcome these gaps. Being designed for specific application domains, these approaches share commonalities as well as orthogonal solutions and can build the foundation of an overall Event-driven Spatial Data Infrastructure.


2011 ◽  
Vol 11 (12) ◽  
pp. 3157-3170 ◽  
Author(s):  
K. Kalabokidis ◽  
N. Athanasis ◽  
M. Vaitis

Abstract. With the proliferation of the geospatial technologies on the Internet, the role of geo-portals (i.e. gateways to Spatial Data Infrastructures) in the area of wildfires management emerges. However, keyword-based techniques often frustrate users when looking for data of interest in geo-portal environments, while little attention has been paid to shift from the conventional keyword-based to navigation-based mechanisms. The presented OntoFire system is an ontology-based geo-portal about wildfires. Through the proposed navigation mechanisms, the relationships between the data can be discovered, which would otherwise not be possible when using conventional querying techniques alone. End users can use the browsing interface to find resources of interest by using the navigation mechanisms provided. Data providers can use the publishing interface to submit new metadata, modify metadata or removing metadata in/from the catalogue. The proposed approach can improve the discovery of valuable information that is necessary to set priorities for disaster mitigation and prevention strategies. OntoFire aspires to be a focal point of integration and management of a very large amount of information, contributing in this way to the dissemination of knowledge and to the preparedness of the operational stakeholders.


2016 ◽  
Vol 7 (3) ◽  
pp. 1-37
Author(s):  
Willington Siabato ◽  
Javier Moya-Honduvilla ◽  
Miguel Ángel Bernabé-Poveda

The way aeronautical information is managed and disseminated must be modernized. Current aeronautical information services (AIS) methods for storing, publishing, disseminating, querying, and updating the volume of data required for the effective management of air traffic control have become obsolete. This does not contribute to preventing airspace congestion, which turns into a limiting factor for economic growth and generates negative effects on the environment. Owing to this, some work plans for improving AIS and air traffic flow focus on data and services interoperability to allow an efficient and coordinated use and exchange of aeronautical information. Geographic information technologies (GIT) and spatial data infrastructures (SDI) are comprehensive technologies upon which any service that integrates geospatial information can rely. The authors are working on the assumption that the foundations and underlying technologies of GIT and SDI can be applied to support aeronautical data and services, considering that aeronautical information contains a large number of geospatial components. This article presents the design, development, and implementation of a Web-based system architecture to evolve and enhance the use and management of aeronautical information in any context, e.g., in aeronautical charts on board, in control towers, and in aeronautical information services. After conducting a study into the use of aeronautical information, it was found that users demand specific requirements regarding reliability, flexibility, customization, integration, standardization, and cost reduction. These issues are not being addressed with existing systems and methods. A system compliant with geographic standards (OGC, ISO) and aeronautical regulations (ICAO, EUROCONTROL) and supported by a scalable and distributed Web architecture is proposed. This proposal would solve the shortcomings identified in the study and provide aeronautical information management (AIM) with new methods and strategies. In order to seek aeronautical data and services interoperability, a comprehensive aeronautical metadata profile has been defined. This proposal facilitates the use, retrieval, updating, querying, and editing of aeronautical information, as well as its exchange between different private and public institutions. The tests and validations have shown that the proposal is achievable.


Survey Review ◽  
2016 ◽  
Vol 50 (360) ◽  
pp. 191-200 ◽  
Author(s):  
Collins Mwange ◽  
Galcano Canny Mulaku ◽  
David N Siriba

2013 ◽  
Author(s):  
Γεώργιος Πανόπουλος

Η σύνθετη φύση του Χρόνου και της Μεταβολής συνεχίζουν να καθιστούν το σχεδιασμό χώρο-χρονικών μοντέλων ως ένα σύνθετο ζήτημα, αν και έχουν πραγματοποιηθεί σημαντικές ερευνητικές εξελίξεις. Παράλληλα, η σύγχρονη τάση στην καταγραφή των γεωγραφικών φαινομένων επιβάλει την συνεκτική και ευρέως προσπελάσιμη περιγραφή τους υπό τη μορφή Υποδομών Χωρικών Πληροφοριών (Spatial Data Infrastructures – SDIs). Σκοπός της παρούσας Διατριβής είναι η διερεύνηση της επέκτασης των Εννοιολογικών Μοντέλων που προδιαγράφονται σε Υποδομές Χωρικών Πληροφοριών, έτσι ώστε να αποδίδουν τη Χώρο-Χρονική συμπεριφορά των Οντοτήτων, και να δίνουν τη δυνατότητα εκτέλεση εργασιών Χώρο-Χρονικής Ανάλυσης. Συγκεκριμένα, δόθηκε έμφαση στην επέκταση του Γενικευμένου Εννοιολογικού Μοντέλου που εφαρμόζεται στην Ευρωπαϊκή Υποδομή Χωρικών Πληροφοριών (INSPIRE), ώστε να συμπληρωθεί με ένα Base Model, το οποίο να μπορεί να χρησιμοποιεί επικουρικά κατά τη σύνταξη των εξειδικευμένων Μοντέλων Δεδομένων (Application Schemas) των 34 Θεματικών Επιπέδων της Οδηγίας. Αν και το Γενικευμένο Εννοιολογικό Μοντέλο του INSPIRE προβλέπει χαρακτηριστικά και UML στερεότυπα για την καταγραφή της χρονικής πληροφορίας, δεν διαθέτει πλήρες Base Model για απόδοση των αντικειμένων ως χώρο-χρονικά.Στην παρούσα διατριβή, αφενός τεκμηριώνονται και αξιολογούνται τα μοντέλα χωρικής αναπαράστασης που υιοθετούνται από τα διεθνή πρότυπα και τις σύγχρονες Χωρικές Υποδομές, και αφετέρου, εισάγονται έννοιες σε ένα μοντέλο το οποίο να είναι ικανό να αντιμετωπίσει χρονικά ζητήματα. Ο στόχος είναι να τυποποιηθούν αυτές οι έννοιες σε ένα ενοποιημένο μοντέλο βάσης δεδομένων, ικανό να διαχειρίζεται όχι μόνο χωρικά ζητήματα, αλλά και τη μεταβολή των φαινομένων. Από την ανάλυση των εξειδικευμένων Application Schemas του INSPIRE εντοπίζονται βασικές απαιτήσεις χώρο-χρονικής ανάλυσης σε εφαρμογές. Αφού διερευνάται η αποτελεσματικότητα των διαθέσιμων δυνατοτήτων αναπαράστασης των χρονικών ιδιοτήτων της Οδηγίας για να αντιμετωπιστούν οι απαιτήσεις αυτές, καθορίζεται η έννοια των Χώρο-Χρονικών Μονάδων (Spatiotemporal Units - STUs) και περιγράφεται η επέκταση του ΓΕΜ του INSPIRE ώστε να συμπεριλάβει την Ταυτότητα και τη Χρονική Μεταβολή. Τα STUs μπορούν να υποβληθούν σε 4 μοναδιαίες μεταβολές, και αυτό αξιοποιείται για να συστηματοποιηθεί ο τρόπος εντοπισμού των ευρύτερων Μεταβολών στα application schemas.Έχοντας ορίσει τις Χώρο-Χρονικές Μονάδες, εξετάζεται η συνεισφορά του προτεινόμενου μοντέλου, με το πώς μπορούν εξυπηρετήσουν τα STUs τις διαδικασίες χώρο-χρονικής Ανάλυσης μέσω των δεδομένων ενός SDI. Ανάγονται οι χρονικές ιδιότητες με τρόπο όμοιο με των χωρικών, ώστε να εκφραστούν έννοιες όπως η Κλίμακα, η Ακρίβεια, η Οπτικοποίηση, και η Γενίκευση, και εξετάζεται ο βαθμός συνεισφοράς των Χώρο-Χρονικών Μονάδων. Ειδικά για την περίπτωση της Χώρο-Χρονικής Εννοιολογικής Γενίκευσης, καθορίζονται τέσσερεις (4) τελεστές, οι οποίοι περιγράφουν πως μπορεί να αλλάξει η χρονική κλίμακα των δεδομένων για ανάγκες ανάλυσης. Τέλος, το προτεινόμενο μοντέλο αξιοποιείται και αξιολογείται σε επίπεδο συγκεκριμένων εφαρμογών, καθώς δοκιμάζεται η υιοθέτηση των STUs ως τύπων αντικειμένων σε ισχύοντα application schemas του INSPIRE


2012 ◽  
Vol 92 (4) ◽  
pp. 63-78
Author(s):  
Dubravka Sladic ◽  
Milan Vrtunski ◽  
Ivan Alargic ◽  
Aleksandra Ristic ◽  
Dusan Petrovacki

The paper presents the implementation of geoportal for landslide monitoring which which includes two subsystems: a system for acquisition, storage and distribution of data on landslides and real time alert system. System for acquisition, storage and distribution of data on landslides include raster and vector spatial data on landslides affected areas, as well as metadata. Alert system in real time is associated with a sensor for detecting displacement, which performs constant measurements and signals in case of exceeding the reference value. The system was developed in accordance with the standards in the field of GIS: ISO 19100 series of standards and OpenGIS Consortium and is based on service-oriented architecture and principles of spatial data infrastructures.


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