A New Relational Spatial OLAP Approach For Multi-resolution and Spatio-multidimensional Analysis of Incomplete Field Data

International audienceIntegrating continuous spatial data into SOLAP systems is a new research challenge. Moreover, representation of field data at different scales or resolutions is often mandatory for an effective analysis. Thus, in this paper, we propose a logical model to integrate spatial dimensions representing incomplete field data at different resolutions in a classical SOLAP architecture

Probabilistic uncertainty in an interoperable framework

This thesis provides an interoperable language for quantifying uncertainty using probability theory. A general introduction to interoperability and uncertainty is given, with particular emphasis on the geospatial domain. Existing interoperable standards used within the geospatial sciences are reviewed, including Geography Markup Language (GML), Observations and Measurements (O&M) and the Web Processing Service (WPS) specifications. The importance of uncertainty in geospatial data is identified and probability theory is examined as a mechanism for quantifying these uncertainties. The Uncertainty Markup Language (UncertML) is presented as a solution to the lack of an interoperable standard for quantifying uncertainty. UncertML is capable of describing uncertainty using statistics, probability distributions or a series of realisations. The capabilities of UncertML are demonstrated through a series of XML examples. This thesis then provides a series of example use cases where UncertML is integrated with existing standards in a variety of applications. The Sensor Observation Service - a service for querying and retrieving sensor-observed data - is extended to provide a standardised method for quantifying the inherent uncertainties in sensor observations. The INTAMAP project demonstrates how UncertML can be used to aid uncertainty propagation using a WPS by allowing UncertML as input and output data. The flexibility of UncertML is demonstrated with an extension to the GML geometry schemas to allow positional uncertainty to be quantified. Further applications and developments of UncertML are discussed

Uncertainty analysis in the Model Web

This thesis provides a set of tools for managing uncertainty in Web-based models and workflows.To support the use of these tools, this thesis firstly provides a framework for exposing models through Web services. An introduction to uncertainty management, Web service interfaces,and workflow standards and technologies is given, with a particular focus on the geospatial domain.An existing specification for exposing geospatial models and processes, theWeb Processing Service (WPS), is critically reviewed. A processing service framework is presented as a solutionto usability issues with the WPS standard. The framework implements support for Simple ObjectAccess Protocol (SOAP), Web Service Description Language (WSDL) and JavaScript Object Notation (JSON), allowing models to be consumed by a variety of tools and software. Strategies for communicating with models from Web service interfaces are discussed, demonstrating the difficultly of exposing existing models on the Web. This thesis then reviews existing mechanisms for uncertainty management, with an emphasis on emulator methods for building efficient statistical surrogate models. A tool is developed to solve accessibility issues with such methods, by providing a Web-based user interface and backend to ease the process of building and integrating emulators. These tools, plus the processing service framework, are applied to a real case study as part of the UncertWeb project. The usability of the framework is proved with the implementation of aWeb-based workflow for predicting future crop yields in the UK, also demonstrating the abilities of the tools for emulator building and integration. Future directions for the development of the tools are discussed

Architectures and Standards for Spatial Data Infrastructures and Digital Government: European Union Location Framework Guidelines

This document provides an overview of the architecture(s) and standards for Spatial Data Infrastructures (SDI) and Digital Government. The document describes the different viewpoints according to the Reference Model for Open and Distributed Processing (RM-ODP) which is often used in both the SDI and e-Government worlds: the enterprise viewpoint, the engineering viewpoint, the information viewpoint, the computational viewpoint and the technological viewpoint. The document not only describes these viewpoints with regard to SDI and e-Government implementations, but also how the architecture(s) and standards of SDI and e-Government relate. It indicates which standards and tools can be used and provides examples of implementations in different areas, such as process modelling, metadata, data and services. In addition, the annex provides an overview of the most commonly used standards and technologies for SDI and e-Government.JRC.B.6-Digital Econom

Proceedings of the 3rd Open Source Geospatial Research & Education Symposium OGRS 2014

The third Open Source Geospatial Research & Education Symposium (OGRS) was held in Helsinki, Finland, on 10 to 13 June 2014. The symposium was hosted and organized by the Department of Civil and Environmental Engineering, Aalto University School of Engineering, in partnership with the OGRS Community, on the Espoo campus of Aalto University. These proceedings contain the 20 papers presented at the symposium. OGRS is a meeting dedicated to exchanging ideas in and results from the development and use of open source geospatial software in both research and education.  The symposium offers several opportunities for discussing, learning, and presenting results, principles, methods and practices while supporting a primary theme: how to carry out research and educate academic students using, contributing to, and launching open source geospatial initiatives. Participating in open source initiatives can potentially boost innovation as a value creating process requiring joint collaborations between academia, foundations, associations, developer communities and industry. Additionally, open source software can improve the efficiency and impact of university education by introducing open and freely usable tools and research results to students, and encouraging them to get involved in projects. This may eventually lead to new community projects and businesses. The symposium contributes to the validation of the open source model in research and education in geoinformatics

Towards BIM/GIS interoperability: A theoretical framework and practical generation of spaces to support infrastructure Asset Management

The past ten years have seen the widespread adoption of Building Information Modelling (BIM) among both the Architectural, Engineering and Construction (AEC) and the Asset Management/ Facilities Management (AM/FM) communities. This has been driven by the use of digital information to support collaborative working and a vision for more efficient reuse of data. Within this context, spatial information is either held in a Geographic Information Systems (GIS) or as Computer-Aided Design (CAD) models in a Common Data Environment (CDE). However, these being heterogeneous systems, there are inevitable interoperability issues that result in poor integration. For this thesis, the interoperability challenges were investigated within a case study to ask: Can a better understanding of the conceptual and technical challenges to the integration of BIM and GIS provide improved support for the management of asset information in the context of a major infrastructure project? Within their respective fields, the terms BIM and GIS have acquired a range of accepted meanings, that do not align well with each other. A seven-level socio-technical framework is developed to harmonise concepts in spatial information systems. This framework is used to explore the interoperability gaps that must be resolved to enable design and construction information to be joined up with operational asset information. The Crossrail GIS and BIM systems were used to investigate some of the interoperability challenges that arise during the design, construction and operation of an infrastructure asset. One particular challenge concerns a missing link between AM-based information and CAD-based geometry which hinders engineering assets from being located within the geometric model and preventing geospatial analysis. A process is developed to link these CAD-based elements with AM-based assets using defined 3D spaces to locate assets. However, other interoperability challenges must first be overcome; firstly, the extraction, transformation and loading of geometry from CAD to GIS; secondly, the creation of an explicit representation of each 3D space from the implicit enclosing geometry. This thesis develops an implementation of the watershed transform algorithm to use real-world Crossrail geometry to generate voxelated interior spaces that can then be converted into a B-Rep mesh for use in 3D GIS. The issues faced at the technical level in this case study provide insight into the differences that must also be addressed at the conceptual level. With this in mind, this thesis develops a Spatial Information System Framework to classify the nature of differences between BIM, GIS and other spatial information systems

Efficient Management for Geospatial and Temporal Data using Ontology-based Data Access Techniques

Το μοντέλο δεδομένων RDF και η γλώσσα επερωτήσεων SPARQL είναι ευρέως διαδεδομένα για την χρήση τους με σκοπό την ενοποίηση πληροφορίας που προέρχεται από διαφορετικές πηγές. Ο αυξανόμενος αριθμός των γεωχωρικών συνόλων δεδομένων που είναι πλέον διαθέσιμα σαν γεωχωρικά διασυνδεδεμένα δεδομένα οδήγησε στην εμφάνιση επεκτάσεων του μοντέλου δεδομένων RDF και της γλώσσας επερωτήσεων SPARQL. Δύο από τις σημαντικότερες επεκτάσεις αυτές είναι η γλώσσα GeoSPARQL, η οποία έγινε OGC πρότυπο, και το πλαίσιο του μοντέλου δεδομένων stRDF και της γλώσσας επερωτήσεων stSPARQL. Και οι δύο προσεγγίσεις μπορούν να χρησιμοποιηθούν για την αναπαράσταση και επερώτηση διασυνδεδεμένων γεωχωρικών δεδομένων, ενώ το μοντέλο stRDF και η γλώσσα stSPARQL παρέχουν επίσης επιπλέον λειτουργικότητα για την αναπαράσταση και επερώτηση χρονικών δεδομένων. Παρότι ο αριθμός των δεδομένων που είναι διαθέσιμα σαν γεωχωρικά ή και χρονικά διασυνδεδεμένα δεδομένα αυξάνεται, η μετατροπή των γεωχωρικών δεδομένων σε RDF και η αποθήκευσή τους σε αποθετήρια RDF δεν είναι πάντα η βέλτιστη λύση, ειδικά όταν τα δεδομένα βρίσκονται εξαρχής σε σχεσιακές βάσεις οι οποίες μπορεί να έχουν αρκετά μεγάλο μέγεθος ή και να ενημερώνονται πολύ συχνά. Στα πλαίσια αυτής της διδακτορικής διατριβής, προτείνουμε μια λύση βασισμένη στην ανάκτηση πληροφορίας με χρήση οντολογιών και αντιστοιχίσεων για την επερώτηση δεδομένων πάνω από γεωχωρικές σχεσιακές βάσεις δεδομένων. Επεκτείνουμε τεχνικές επανεγγραφής GeoSPARQL ερωτημάτων σε SQL ώστε η αποτίμηση των επερωτήσεων να γίνεται εξολοκλήρου στο γεωχωρικό σύστημα διαχείρισης βάσεων δεδομένων. Επίσης, εισαγάγουμε επιπλέον λειτουργικότητα στη χρονική συνιστώσα του μοντέλου δεδομένων stRDF και της γλώσσας επερωτήσεων stSPARQL, προκειμένου να διευκολυνθεί η υποστήριξη χρονικών τελεστών σε συστήματα OBDA. Στη συνέχεια, επεκτείνουμε τις παραπάνω μεθόδους με την υποστήριξη διαφορετικών πηγών δεδομένων πέρα από σχεσιακές βάσεις και παρουσιάζουμε μια OBDA προσέγγιση που επιτρέπει τη δημιουργία εικονικών RDF γράφων πάνω από δεδομένα που βρίσκονται διαθέσιμα στο διαδίκτυο σε διάφορες μορφές (πχ. HTML πίνακες, web διεπαφές), με χρήση οντολογιών και αντιστοιχίσεων. Συγκρίναμε την απόδοση του συστήματός μας με ένα σχετικό σύστημα και τα αποτελέσματα έδειξαν ότι πέραν του ότι το σύστημά μας παρέχει μεγαλύτερη λειτουργικότητα (πχ. υποστηρίζει περισσότερα είδη πηγών δεδομένων, περιλαμβάνει απλούστερες διαδικασίες και εξασφαλίζει καλύτερη απόδοση. Τέλος, παρουσιάζουμε την εφαρμογή των μεθόδων και συστημάτων που περιγράφονται στη διατριβή σε πραγματικά σενάρια χρήσης.The data model RDF and query language SPARQL have been widely used for the integration of data coming from different souces. Due to the increasing number of geospatial datasets that are being available as linked open data, a lot of effort focuses in the development of geospatial (and temporal, accordingly) extensions of the framework of RDF and SPARQL. Two highlights of these efforts are the query language GeoSPARQL, that is an OGC standard, and the framework of stRDF and stSPARQL. Both frameworks can be used for the representation and querying of linked geospatial data, and stSPARQL also includes a temporal dimension. Although a lot of geospatial (and some temporal) RDF stores started to emerge, converting geospatial data into RDF and then storing it into an RDF stores is not always best practice, especially when the data exists in a relational database that is fairly large and/or it gets updated frequently. In this thesis, we propose an Ontology-based Data Access (OBDA) approach for accessing geospatial data stored in geospatial relational databases, using the OGC standard GeoSPARQL and R2RML or OBDA mappings. We introduce extensions to an existing SPARQL-to-SQL translation method to support GeoSPARQL features. We describe the implementation of our approach in the system Ontop-spatial, an extension of the OBDA system Ontop for creating virtual geospatial RDF graphs on top of geospatial relational databases. Ontop-spatial is the first geospatial OBDA system and outperforms state-of-the-art geospatial RDF stores. We also show how to answer queries with temproal operators in the OBDA framework, by utilizing the framework stRDF and the query language stSPARQL which we extend with some new features. Next, we extend the data sources supported by Ontop-spatial going beyond relational database management systems, and we present our OBDA solutions for creating virtual RDF graphs on top of various web data sources (e.g., HTML tables, Web APIs) using ontologies and mappings. We compared the performance of our approach with a related implementation and evaluation results showed that not only does Ontop-spatial support more functionalities (e.g., more data sources, more simple workflow), but it also achieves better performance. Last, we describe how the work described in this thesis is applied in real-world application scenarios

Spatial ontologies for architectural heritage

Informatics and artificial intelligence have generated new requirements for digital archiving, information, and documentation. Semantic interoperability has become fundamental for the management and sharing of information. The constraints to data interpretation enable both database interoperability, for data and schemas sharing and reuse, and information retrieval in large datasets. Another challenging issue is the exploitation of automated reasoning possibilities. The solution is the use of domain ontologies as a reference for data modelling in information systems. The architectural heritage (AH) domain is considered in this thesis. The documentation in this field, particularly complex and multifaceted, is well-known to be critical for the preservation, knowledge, and promotion of the monuments. For these reasons, digital inventories, also exploiting standards and new semantic technologies, are developed by international organisations (Getty Institute, ONU, European Union). Geometric and geographic information is essential part of a monument. It is composed by a number of aspects (spatial, topological, and mereological relations; accuracy; multi-scale representation; time; etc.). Currently, geomatics permits the obtaining of very accurate and dense 3D models (possibly enriched with textures) and derived products, in both raster and vector format. Many standards were published for the geographic field or in the cultural heritage domain. However, the first ones are limited in the foreseen representation scales (the maximum is achieved by OGC CityGML), and the semantic values do not consider the full semantic richness of AH. The second ones (especially the core ontology CIDOC – CRM, the Conceptual Reference Model of the Documentation Commettee of the International Council of Museums) were employed to document museums’ objects. Even if it was recently extended to standing buildings and a spatial extension was included, the integration of complex 3D models has not yet been achieved. In this thesis, the aspects (especially spatial issues) to consider in the documentation of monuments are analysed. In the light of them, the OGC CityGML is extended for the management of AH complexity. An approach ‘from the landscape to the detail’ is used, for considering the monument in a wider system, which is essential for analysis and reasoning about such complex objects. An implementation test is conducted on a case study, preferring open source applications