Resumen de Contributions to the interoperability of hydrological information systems based on spatial data infrastructures

Miguel A. Latre Abadía

• 1. OBJECTIVE The objective of the PhD dissertation is to strengthen the link between GIScience research and the environmental field, by applying concepts and state-of-the-art developments form the spatial data infrastructure domain in the solutions to problems in the environmental field in general, and in the hydrological area in particular. Several contributions are presented, where different aspects of the management of spatial information are applied to the environmental field. These contributions are related to metadata, the semantic improvement of the retrieval of environmental spatial information and the application of the SDI architectural model in geoprocessing workflows that resolve different environmental management problems. This relation has been further analysed by considering also elements from e-government theory.

  2. METHODOLOGY The methodology followed in the PhD consisted in the study of the relevant technologies, standards and legislation presented in the introduction to the dissertation with the aim of applying them in a joint mode to solve specific environmental domain problems.

  The study of these standards, technological developments and legislation has been driven by the participation of the PhD candidate's research group in different research projects: - Sixteen projects with the Hydrological Panning Office of Ebro River Basin Authority (Confederación Hidrográfica del Ebro).

  - The development of the Spanish National Spatial Data Infrastructure (Infraestructura de Datos Espaciales de España) for the Spanish Mapping Agency (Instituto Geográfico Nacional).

  - The SDIGER project [1]: A pilot project for the INSPIRE Directive, aimed at testing the feasibility of developing a cross-border inter-administration SDI to support WFD information access (Zarazaga-Soria et al., 2007).

  - The EuroGEOSS project: A 7th Framework Program project of the European Commission working on a European approach to GEOSS. EuroGEOSS [2] focused on the three thematic areas of drought, biodiversity and forest with the objective to build interoperable infrastructures for each of the disciplines as well as an infrastructure supporting multi-disciplinary interoperability across disciplines.

  Among them, the SDIGER project opened a set of lines of research related to geospatial information, metadata and spatial data infrastructures that were the starting point of the PhD dissertation. SDIGER aimed at testing solutions for sharing spatial data and services following INSPIRE principles, estimating the costs, and finding the problems and obstacles of implementing interoperability-based solutions on the basis of real cases. Among the different activities carried out, three metadata profiles with full technical documentation and user guides were developed (for geographical data mining, for assessing and using geographical data, and for the WFD), an open source metadata management tool with support for the aforementioned profiles was delivered, and two web SDI-based applications were developed: WFD reporting under its 5th article and water abstraction request. The PhD candidate made and evaluation and assessment of the SDIGER WFD metadata profile by confronting it to the WFD reporting sheets and by linking it to the WFD reporting web application. This work derived in the two related lines of research than can be distinguished among the papers that compose the dissertation:

  - Metadata in the environmental area, that later evolved in the semantic improvement of the retrieval of environmental data in multilingual environments and in the refactoring of the metadata editing tool.

  - Application of the SDI architectural model to the workflow of environmental management problems.

  3. STRUCTURE OF THE DISSERTATION The PhD dissertation is a compendium of the following previously published papers:

  1. J. Nogueras-Iso, M. Á. Latre, R. Béjar, P. R. Muro-Medrano, and F. J. Zarazaga-Soria. A model driven approach for the development of metadata editors, applicability to the annotation of geographic information resources. Data&Knowledge Engineering, 81-82: 118-139, 2012. doi: 10.1016/j.datak.2012.09.001. URL http://dx.doi.org/10.1016/j.datak.2012.09.001 2. M. Á. Latre, J. Lacasta, E. Mojica, J. Nogueras-Iso, and F. J. Zarazaga-Soria. An approach to facilitate the integration of hydrological data by means of ontologies and multilingual thesauri. In M. Sester, L. Bernard, and V. Paelke, editors, Advances in GIScience, Lecture Notes in Geoinformation and Cartography, pages 155-171. Springer Berlin Heidelberg, Apr. 2009. doi: 10.1007/978-3-642-00318-9_8. URL http://www.springerlink.com/content/u7834577527w04l6 3. M. Á. Latre, B. Hofer, J. Lacasta, and J. Nogueras-Iso. The development and interlinkage of a drought vocabulary in the EuroGEOSS interoperable catalogue infrastructure. International Journal of Spatial Data Infrastructures Research, 7:225-248, 2012. ISSN 1725-0463. doi: 10.2902/1725-0463.2012.07.art12. URL http://ijsdir.jrc.ec. europa.eu/index.php/ijsdir/article/view/264 4. R. Béjar, M. Á. Latre, F. J. Lopez-Pellicer, J. Nogueras-Iso, F. J. Zarazaga-Soria, and P. R. Muro-Medrano. SDI-based business processes: A territorial analysis web information system in Spain. Computers & Geosciences, 46:66-72, Sept. 2012. ISSN 0098-3004. doi: 10.1016/j.cageo.2012.04.010. URL http://www.sciencedirect.com/ science/article/pii/S0098300412001331 5. J. A. Álvarez-Robles, F. J. Zarazaga-Soria, M. Á. Latre, R. Béjar, and P. R. Muro-Medrano. Water quality monitoring to support the European Commission's Water Framework Directive reporting requirements. Transactions in GIS, 11(6):835-847, December 2007. ISSN 1361-1682. doi: 10.1111/j.1467-9671.2007. 01077.x. URL http://onlinelibrary.wiley.com/doi/10.1111/j.1467-9671.2007.01077.x/abstract 6. M. Á. Latre, F. J. Lopez-Pellicer, J. Nogueras-Iso, R. Béjar, F. J. Zarazaga-Soria, and P. R. Muro-Medrano. Spatial data infrastructures for environmental e-government services: the case of water abstractions authorisations. Environmental Modelling & Software, 48:81-92, Oct. 2013. ISSN 1364-8152. doi: 10.1016/j.envsoft.2013.06.005. URL http://www.sciencedirect.com/science/article/pii/S1364815213001412 The first three are centred on metadata management and the semantic improvement of the retrieval of environmental geospatial information. "A model driven approach for the development of metadata editors, applicability to the annotation of geographic information resources" proposes a Model Driven Architecture (MDA) approach to metadata edition tools and applies that approach to an open source metadata tool, CatMDEdit. "An Approach to Facilitate the Integration of Hydrological Data by means of Ontologies and Multilingual Thesauri" introduces a hydrologic data retrieval system that makes use of a multilingual thesaurus for the hydrology domain specifically generated for that system. "The development and interlinkage of a drought vocabulary in the EuroGEOSS Interoperable Catalogue Infrastructure" presents the development of a drought vocabulary and analyses how the retrieval of drought related datasets in the European Drought Observatory catalogue improved after the adoption of the aforementioned vocabulary.

  The next three papers apply the SDI architectural model in the development of applications that solve problems in the environmental field. "SDI-based business processes: A territorial analysis web information system in Spain" presents how the web services that compose an SDI can be chained to solve particular problems of territorial analysis. The paper presents three particular uses cases that can be implemented with the services of the Spanish Spatial Data Infrastructure. Two of these uses cases are particularly linked with the environment: Urban Growth Analysis in a Municipality and Dam Heightening Effect on Agricultural Areas. "Water Quality Monitoring to Support the European Commission's Water Framework Directive Reporting Requirements" applies SDI architectural model in a study where water quality in the Ebro basin was estimating by means of remote sensing. The application of SDIs to the geoprocessing workflow was challenging but significantly improved it. Finally, "Spatial Data Infrastructures for Environmental E-government Services: the case of Water Abstractions Authorisations" focuses in the relation among spatial data infrastructures, e-government theory and environmental management. The analysis performed is illustrated by means of a transaction-level e-government application for requesting water abstractions authorisations.

  A report justifying the thematic unity of the papers is enclosed to the PhD dissertation. The report includes an explanation of the objective, methodology, structure of the dissertation, the research issues it addresses and its conclusions. The report also introduces state-of-the-art concepts, artifacts and technologies related to the dissertation: geospatial, environmental and hydrological information; spatial data infrastructures; metadata, thesauri and ontologies; ISO/TC 211 and OGC standards; and related European directives: "Infrastructure for spatial information in Europe", "Public access to environmental information", "Re-use of public sector information directives" and "Water framework directive".

  The dissertation is finished by an appendix containing additional information on the papers that compose the dissertation: the impact factors of the journals where the papers have been published and the justification of the PhD candidate contribution for each of the publications.

  4. CONCLUSIONS As a recompilation of the main results of the dissertation the contributions could be summarised as follows:

  - Chapter 2 presents the guidelines to apply an MDA approach for the development of annotation tools, which can be customised to different metadata standards and profiles with minimum effort. By applying this approach, experts in metadata standards (without any special programming skills) can focus their efforts on the definition of new metadata models using a domain specific language (the one used to define platform independent models), whose abstraction level is close to the way of expressing metadata standards in the documents provided by standardisation bodies. After this high-level definition, the PIM models are automatically transformed into the platform specific models and configuration files required by the specific metadata editor that has been chosen as the final platform for annotating resources.

  The feasibility of these guidelines for applying MDA was tested with CatMDEdit, an open source metadata editor supporting multiple metadata standards and profiles. Following this MDA approach, 11 metadata profiles derived from ISO 19115 and Dublin Core have been incorporated in CatMDEdit for the annotation of geographic information resources.

  - Chapter 3 focuses on the topic of integration of hydrological data by means of ontologies and multilingual thesauri for information discovery and retrieval. It presents an information retrieval system that facilitates the integration of hydrologic data and the discovery of implicit relations between features, not usually found directly in local data repositories. The relation between the searched and the conceptual entities that are related to local repositories is found via a multilingual thesaurus generated starting from a set of thesauri from different knowledge areas and a selected list of terms focused on the domain. The system takes as input a search term or query, uses the multilingual thesaurus to expand it, locates and queries appropriate Web Feature Services, and finally returns the results as a map or as a feature collection.

  - The development and linkage of a drought vocabulary for an interoperable catalogue is the result of Chapter 4. It was showed that other proposed vocabularies in the European project EuroGEOSS for the annotation of metadata were, in the particular thematic area of drought, either too generic to adequately classify drought resources, or too large to be practical for their annotation. As a consequence, a drought vocabulary was developed in order to improve the accessibility to appropriate drought resources (datasets and services) to users and experts. A collaborative methodology for the creation of a specific drought vocabulary is presented in the paper, and a 103-term vocabulary, organised into a hierarchy and translated into 15 languages, was developed.

  This vocabulary was first used in the EuroGEOSS drought catalogue in three ways. Firstly, by annotating the resources it holds according to the new vocabulary, since the quality of the search results of a catalogue query depended on the quality of the metadata. A 51.5% of the drought vocabulary concepts were used in the annotation of the EuroGEOSS drought catalogue resources. Secondly, it was included in the user search application interface. Analysis from the catalogue logs showed that it improved the interaction with users, helping them to establish their searching parameters. The fact that the vocabulary was used both in the metadata and in the user search application helped to improve the search results. Logs also showed that the terms selected to be part of the vocabulary were appropriate from a user's point of view, since 65.0% of them have been used in at least a query. Finally, the vocabulary was been aligned with the other two thesauri chosen for metadata annotation in the project: GEMET and GEOSS Societal Benefit Areas categories.

  - Chapter 5 focuses on the interoperability of web information systems based on SDI strategy, and uses the territorial analysis domain as a case study. The territorial analysis web information system provides specific support to different geospatial business processes. This information system, established by the Spanish National SDI, gave access to land cover, topography, elevation data, and a number of geospatial operations through different SDI services. The SDI services used by the information system come from two different SDIs, Spain SDI and IGN SDI. This is a good example of how different providers can be combined together to build new applications, thanks to their respective efforts to set up SDIs.

  A service-oriented architecture for the information system based on Spatial Data Infrastructures was described. Several examples of the geospatial processes that are supported were also presented. It has been shown how these processes can be facilitated by means of a Web application GUI accessing to the services of the architecture. How geoscientists and other GIS professionals can include the services in their own business processes and workflows was also discussed. The work demonstrates the adequacy of the use of Spatial Data Infrastructures for business processes in another kind of environmental related area such as territorial analysis, but that also it establishes the basis to extend its application to other related environmental domain areas.

  - SDI can also be used to easy water quality monitoring support for WFD reporting requirements, which has been the purpose of Chapter 6. In this part of the work a geoprocessing workflow that demonstrated the viability of using a SDI and remote sensing techniques for reaching a specific objective has been proposed, in this case, for assessing the quality of water bodies. The work within a SDI, although initially increased the amount of work, proved to be highly useful, not only in searching and selecting the most appropriate data, avoiding the replication of work previously done, but also in increasing the understanding of the data by examining its metadata.

  At the moment the study was performed, only certain parts of the Ebro River Basin Authority SDI were available: conceptual data model of the hydrologic features managed by the Hydrologic Planning Office of the Ebro River Basin Authority, metadata of the data within the model, access applications for the management of these data, catalogue services and searches, web feature service and gazetteer. The methodology proposed to determine water quality using satellite imagery made use of the available services and served to identify different user needs of the system: criteria for searching data, metadata attributes needed, addition, update and retrieval of data requirements (both in terms of models and format). Nowadays, with the Ebro SDI fully implemented, the workflow would have been implemented as a Web Processing Service that could have been integrated into the SDI as well.

  - The adequacy of the use of SDI for environmental e-government services, and its application to a case study in water abstractions authorisations is demonstrated in Chapter 7. Having interoperable and harmonised environmental data is considered of such importance that the political leadership of the EU Environment Directorate-General developed a specific directive, INSPIRE, aiming specifically at establishing a European SDI as a means to achieve the above.

  SDIs can be considered the framework to support environment-related e-government services, allowing to reach a significant level in e-government maturity models. The many initiatives and legal obligations to build SDIs support by themselves e-government services at the level of diffusion of information. In addition to that, SDI principles, combining spatial data from different sources in a consistent way and sharing among several users and applications, have led to a set of implementations rules that ensure horizontal, vertical and geographical integration of geospatial data. In this way, SDIs can also be used as a base for the development of e-government services at the maturity levels of interaction and transaction. In the case of e-government services related to geospatial information, the stages of vertical and horizontal integration proposed by, among others, Layne and Lee (2001) are not really stages after the transaction level, but requirements to achieve the levels of interaction and transaction. This way, any service built on SDIs is contributing to partially achieve the transformation level of e-government, with respect to horizontal and vertical geospatial data integration. An additional kind of integration, geographical integration (integration of information trough neighbour organisations) can be identified in this case.

  The chapter also presents, as a proof-of-concept, a real application in the area of the environment-related permits: the process of applying for a water abstraction authorisation, built as part of the SDIGER project. In this example, SDI services are used for the capture, management, and assessment of geospatial information in a transactional level e-government service, where it is necessary to access data and services from different providers, and from different themes. The use of the SDIs maintained by the different authorities involved allows integrating data and services in the hydrological domain between the main provider, a river basin authority, and the ministry this authority depends on (vertical integration). It also integrates data and services in other domains (orthoimagery or cadastre, for example) between the authority and a mapping agency (horizontal integration), and data and services with neighbouring water agencies (geographical integration).

  REFERENCES J. A. Álvarez-Robles, F. J. Zarazaga-Soria, M. Á. Latre, R. Béjar, and P. R. Muro-Medrano. Water quality monitoring to support the European Commission's Water Framework Directive reporting requirements. Transactions in GIS, 11(6):835-847, December 2007. ISSN 1361-1682. doi: 10.1111/j.1467-9671.2007. 01077.x. URL http://onlinelibrary.wiley.com/doi/10.1111/j.1467-9671.2007.01077.x/abstract R. Béjar, M. Á. Latre, F. J. Lopez-Pellicer, J. Nogueras-Iso, F. J. Zarazaga-Soria, and P. R. Muro-Medrano. SDI-based business processes: A territorial analysis web information system in Spain. Computers & Geosciences, 46:66-72, Sept. 2012. ISSN 0098-3004. doi: 10.1016/j.cageo.2012.04.010. URL http://www.sciencedirect.com/ science/article/pii/S0098300412001331 M. Á. Latre, J. Lacasta, E. Mojica, J. Nogueras-Iso, and F. J. Zarazaga-Soria. An approach to facilitate the integration of hydrological data by means of ontologies and multilingual thesauri. In M. Sester, L. Bernard, and V. Paelke, editors, Advances in GIScience, Lecture Notes in Geoinformation and Cartography, pages 155-171. Springer Berlin Heidelberg, Apr. 2009. doi: 10.1007/978-3-642-00318-9_8. URL http://www.springerlink.com/content/u7834577527w04l6 M. Á. Latre, B. Hofer, J. Lacasta, and J. Nogueras-Iso. The development and interlinkage of a drought vocabulary in the EuroGEOSS interoperable catalogue infrastructure. International Journal of Spatial Data Infrastructures Research, 7:225-248, 2012. ISSN 1725-0463. doi: 10.2902/1725-0463.2012.07.art12. URL http://ijsdir.jrc.ec. europa.eu/index.php/ijsdir/article/view/264 M. Á. Latre, F. J. Lopez-Pellicer, J. Nogueras-Iso, R. Béjar, F. J. Zarazaga-Soria, and P. R. Muro-Medrano. Spatial data infrastructures for environmental e-government services: the case of water abstractions authorisations. Environmental Modelling & Software, 48:81-92, Oct. 2013. ISSN 1364-8152. doi: 10.1016/j.envsoft.2013.06.005. URL http://www.sciencedirect.com/science/article/pii/S1364815213001412 K. Layne and J. Lee. Developing fully functional e-government: A four stage model. Government Information Quarterly, 18(2):122-136, 2001. ISSN 0740-624X. doi: 10.1016/S0740-624X(01)00066-1. URL http://dx.doi.org/10.1016/S0740-624X(01)00066-1.

  J. Nogueras-Iso, M. Á. Latre, R. Béjar, P. R. Muro-Medrano, and F. J. Zarazaga-Soria. A model driven approach for the development of metadata editors, applicability to the annotation of geographic information resources. Data&Knowledge Engineering, 81-82: 118-139, 2012. doi: 10.1016/j.datak.2012.09.001. URL http://dx.doi.org/10.1016/j.datak.2012.09.001 F. J. Zarazaga-Soria, J. Nogueras-Iso, M. Á. Latre, A. Rodríguez, E. López, P. Vivas, and P. R. Muro-Medrano. Providing spatial data infrastructure services in a cross-border scenario: the SDIGER project. In H. Onsrud, editor, Research and TheoryinAdvancing Spatial Data Infrastructure Concepts, pages 107-119. ESRI Press, 2007. ISBN 978-1-58948-162-6. URL http://www.gsdidocs.org/gsdiconf/GSDI-9/papers/TS31.1paper.pdf.

  NOTES [1] http://sdiger.unizar.es/ [2] http://www.eurogeoss.eu/