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METADATA APPLICATION IN COASTAL ZONE MANAGEMENT Rainer Lehfeldt 1 and Carsten Heidmann 2 ABSTRACT The detailed documentation of distributed resources with a standardized metadata profile of ISO 19115 for the coastal zone is used in a German research and development project to provide an integrated view of data and information that is relevant for Integrated Coastal Zone Management tasks. A new editor for creation and maintenance of metadata is part of a web portal, which also provides web services to carry out data discovery and perform simple analysis and visualization inspection. 1.
INTRODUCTION
The German Coastal Engineering Research Council KFKI (GCERC) has initiated a three-year research and development project in 2000 in order to establish a North Sea and Baltic Sea Coastal Information System NOKIS3, which is permanently hosted by the Federal Waterways Engineering and Research Institute BAW in Hamburg. Emphasis is on supplying relevant information and context for coastal data and related publications by cataloguing distributed resources such as bibliographic information, viz. the German journal "Die Küste” and accompanying documents of coastal research projects, GIS resources in the German coastal zone of the North Sea and Baltic Sea, data sets archived in various research databases, viz. data, maps, photographs, remote sensing resources, and documentation of modeling results. In particular, the abstracts of all papers in the German journal “Die Küste” and information concerning on-going and completed research projects provide a thorough review of coastal research and development activities. Digital documents of all recent project reports are available online through the Web portal shown in Figure1. Full text indexing has been implemented for the complete NOKIS metadata base and some additional external metadata archives. Any keywords can be used to search for data, reports and their corresponding providers. The portal is bilingual to support international communication and exchange. It provides a standardized information infrastructure as outlined by Lehfeldt and Heidmann (2003) to support the information needs of Integrated Coastal Zone Management (ICZM). 1
Dr.-Ing., Senior Research-Scientist, Federal Waterways Engineering and Research Institute BAW, Wedeler Landstrasse 157, 22559 Hamburg, Germany (
[email protected]) 2 Dipl.-Geogr., Researcher, Federal Waterways Engineering and Research Institute BAW, Wedeler Landstrasse 157, 22559 Hamburg, Germany (
[email protected]) 3 NOKIS = Nord- und Ostsee Küsten-Informations-System = North Sea and Baltic Sea Coastal Information System
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Standardized metadata are the core of automated search procedures, which help finding relevant data for decision-making and administrative purposes. In recent years, the information sharing process in Germany focuses on the ISO 19115 (2002) standard for metadata. The companion standard ISO 19119 (2002) for web services defines the interface to metadata-driven web-based software methods with which to use discovered data, either in visualization and simple analysis tools or in web portals of e-Government for ordering and buying data products.
Figure 1 NOKIS web portal http://nokis.baw.de Well-established interoperability of web services and distributed data resources is necessary to facilitate vertical information flow between regional, national and international information systems, e.g. the European Environmental Agency. It is equally important for horizontal exchange of information and data between local authorities who prepare the required integrated information products. In addition, the cooperation and participation processes that make up Integrated Coastal Management rely to a great deal on information issues. Therefore, the European Commission (1999) pursues the implementation of national strategies for the collection, processing and diffusion of data and information. The technological background for these aims are web portals and high quality metadata, which facilitate breaking up sectoral views of traditional disciplines such as, e.g., coastal defense and ecology, and support integrated assessment of existing resources. 2.
THE NOKIS CONCEPT
The metadata information system NOKIS is primarily intended to catalogue and discover coastal information, which is archived and maintained in German engineering and research institutions. It has been developed by a team of scientists and engineers from various coastal authorities, who rep-
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resent typical data providers and data users from the coastal zone: Federal Administration of Waterways and Navigation, Lower Saxony Water Management and Coastal Defense Agency, Regional State Office for the Rural Areas Husum, National Park Offices of the Wadden Sea in Lower Saxony and Schleswig-Holstein, Federal Waterways Engineering and Research Institute, and the German Coastal Engineering Research Council. Provision of standardized metadata facilitates the use and understanding of data from distributed institutions and different areas of expertise and contributes to quality assurance. Following the definition of a suitable ISO19115 metadata profile for the coastal zone, a corresponding metadata editor was developed to support creation and maintenance of metadata. Starting in 2002, the participating institutions use this editor in practice to document all locally existing data sets, GIS-files, related reports and publications according to the adopted metadata profile. All local metadata are replicated on the central NOKIS server and published through the NOKIS web portal. Utilization of the system stimulates and intensifies communication and the exchange of information and data in the coastal community. Heidmann and Lehfeldt (2004) outline the technical details of the NOKIS metadata information system, which is based on an open and optionally expandable concept. The map server and database management are Open-Source-Software and the newly developed metadata editor is available for all institutions, which commit themselves to provide metadata for NOKIS. Additional partners have been attracted during the pilot phase to join. The Water Framework Directive of the European Community, WFD (2000), has put forward new and comprehensive reporting obligations with regard to the state of coastal water bodies. These have to be met by coastal authorities who intend to apply standardized web services for production and publication of reports. The aims for the coming project years 2004-2008 are further harmonization of metadata through definition of additional metadata profiles for environmental monitoring and provision of services for ICZM and WFD user groups to integrate data from distributed resources. 3.
METADATA STANDARD FOR THE COASTAL ZONE
Lehfeldt et al. (2002) have presented details of the metadata profile adopted by the NOKIS-project. This subset of ISO19115 reflects the needs of different user communities in the coastal zone. By taking into account the FGDC (2000) Shoreline Profile, the documentation of geographical data sets that intersect with the shoreline also includes information about tidal and marine weather conditions for better data quality assessment. The NOKIS metadata profile requires 23 mandatory elements that focus on identification, use constraints, and data quality to provide optimum information for horizontal data sharing and vertical information dissemination. The most important metadata applied in discovery services are geographic and temporal coverages as well as significant keywords. The geographic location given as coordinates of a bounding box is vital meta information in map-based search mechanisms. Displaying spatial coverages of data sets and project areas on mapservers is helpful information for users and directly indicates regional availability of data. Details about the temporal coverages can act as additional filter in search procedures when given either as periods for collections of time series or as time stamps for field measurements. Descriptive keywords and data set topic categories are classical elements of bibliographical indexing. ISO19115 provides an authoritative list of topic categories, which does not cover the coastal zone in much detail, however. Coastal information is classified as “oceans”, other relevant terms being “inland waters, geo-scientific information and environment”. As existing thesauri, at least in German, do not focus very much on standardized vocabulary of coastal engineering terms, NOKIS addresses the obvious need for compiling significant vocabulary to index data sources and
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pertaining documents. In addition to the native language, NOKIS requires keywords in English to support international communication. There is still a lack of consistent geographic names for coastal regions of the North Sea, in particular the intertidal wadden areas, and for the micro-tidal lagoon systems along the Southern Baltic Sea. The current Getty Thesaurus (2000) of Geographic Names takes aquatic coastal identifiers or names only partially into account. Other reliable sources need to be collected to enable complementary use of geographic coordinates and geographic names in a map-server environments of ICZM and WFD applications Reference systems for geographic and temporal identifiers are important meta-information for coastal data sets. NOKIS explicitly references the European Petroleum Survey Group (2002) in this context, which is also compliant with ISO 19111 Spatial Referencing by Coordinates as part of the ISO Series on geographic information. 4.
TOOLS FOR METADATA
A multi-lingual metadata editor has been developed in cooperation with practitioners from the partner institutions. They all use this tool to document their local databases with the NOKIS metadata profile. Since there are metadata elements, which contain direct links to electronically available material, the NOKIS editor is more than an authoring tool for metadata acquisition. In practise, it serves as front-end to local databases of field data, maps and literature, and provides a user-friendly interface for discovery and access of data.
Figure 2 Metadata export via XML file Figure 3 NOKIS metadata editor A built-in import/export mechanism facilitates cooperation with established GIS systems and global meta-information systems. The NOKIS metadata profile, being an ISO19115 profile, can eas-
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ily be mapped to the other binding information systems in Germany, namely the environmental data catalog UDK (2004) and the German geospatial data infrastructure GDI-DE (2004). 4.1
Editing
Figure 2 shows an XML presentation of metadata, which are stored in a local PostgreSQL database. The editor can create these files for metadata transfer either to the central NOKIS server or to other systems. The import of ArcGIS metadata also uses XML files. A context sensitive help system guides the user through the elements of the metadata profile. It provides explanations of the items and examples of good practice collected during the first year of application. Figure 3 shows the layout of the editor and the document sections, which directly correspond to the ISO19115 metadata elements for content information, spatial representation, distribution information, and data quality. Clearly arranged forms collect the individual metadata entries for each section. The required input is made either by selection from standardized dropdown lists, by otherwise standardized input, e.g., following conventions for “date” and “time”, or by free text. 4.2
Previewing
Figure 4 shows metadata for a detailed map and an aerial photograph, which contain preview pictures as meta-information that provides an illustration of the dataset. There are a number of coastal data where thumbnails can characterize the content in a concise way. The quality of time series of hydrological or meteorological parameters (wind, water level, velocity, waves etc), for instance, can quickly be estimated by visual inspection. Another example is areas covered by sea surveys that are easily recognized when plotted with corresponding shorelines.
Figure 4 Thumbnails as metadata
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The detailed metadata model supports automated text- and number-based search procedures during the discovery process, which can incorporate pre-selected topics on customized user interfaces for different user groups. Additional preview graphics provide quick overviews of data quality and thus play an important role in data assessment. The NOKIS metadata editor handles both aspects and can serve as graphical index to data holdings. 5.
WEB SERVICES FOR ICZM BASED ON METADATA
A functioning Integrated Coastal Zone Management depends on an information infrastructure that allows online enquiry of geo-information and access to further relevant resources. The publication of standardized metadata describing data and services is one major component of web portals to support automated data discovery. The second component is the provision of common ways to access distributed data with visualization methods, which allow different views for individual user groups to gain understanding of the data. Figure 5 shows a project information form, which is produced for all German coastal research projects. It displays typical meta-information and has direct links to the related digital reports and other web sites. Full text indexing of the NOKIS web portal is performed with the ht://Dig-system (2002). The information gathering follows all hyperlinks in specified domains and creates individual search databases. In this way, we are also able to index external web sites that might have collections of informal meta-information.
Figure 5 Display of project characteristics
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In addition to these text-based search options, NOKIS provides a combination of map-based selection tools that evaluate the spatial extent and topic-based selection criteria, which make use either of given keywords or given full-text indexing of the available ISO19115 compliant metadata. 5.1
Map server
Map servers are the natural front end to spatial metadata. Figure 6 shows the NOKIS implementation of the open source University of Minnesota map server (2003), which displays a layer with sites of coastal administrations and research institutes in northern Germany. A popup window indicates the metadata “contact information” including active links to the respective home pages for each location selected from this map. This presentation is an aggregation of meta-information resulting from the collection of metadata concerning research projects of Figure 5 and supports thematic and institutional associations by the user. The NOKIS map server also allows identification of research projects related to certain areas of the coastal zone, which can be selected by interactively opening up a bounding-box. The system returns a list with links to relevant projects from where access to data and reports is possible.
Figure 6 NOKIS map-server This exploratory application of the metadata base makes research and development issues transparent and helps avoiding reduplicating efforts. The aim of the coming project years is to use these instruments to establish a planning tool for integrated coastal surveys, which will help coordinating Federal and State activities.
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Interactive map – Wind data
The detailed metadata model of ISO 19115 (2002) provides all the information necessary to lay out user-friendly access schemes for field data. Since each set of metadata specifies a “geographic location”4 given as bounding box, bounding polygon, geographic coordinates or geographic name, a spatial representation can be plotted in an interactive map. Panel a in Figure 7 shows an example of two wind measurement sites in coastal waters of the southern Baltic Sea. Their locations are mapped with a symbol and the name of the site, which are linked to the pertaining data sets. When the user selects a site, the respective data are displayed by web services, which provide by default views of this data type most often demanded in practice.
a) Map based selection of measurement sites
b) Plotting time series of velocity and direction, display of stick diagram
c) Polar diagram of wind statistics d) Frequency matrix for wind velocity and directional classes Figure 7 Web services for wind data
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For details see the interactive help system of the NOKIS metadata editor at URL http://nokis.baw.de/editor
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The other topic-tabs allow the user to switch between recordings of wind or water level and, as presented by Lehfeldt et al. (2002), surveys of bathymetry or beach profiles. Due to the given metadata entries for “keywords” and the classification of “keyword type”, the data sets are easily sorted into the topics to be displayed on different tabs of the user interface. The “keyword type” metadata element is an authoritative list4 of “subject matter used to group similar keywords” in the ISO 19115 standard with values of “discipline, place, stratum, temporal and theme”, while the “keyword” metadata element can have any entry to describe the subject. This example clearly demonstrates the benefit of documenting data sets with an in-depth metadata profile. Careful provision of “data about data” not only provides consistent reliable documentation but also has a sustainable effect on data handling. The selected wind data set can be viewed as analogue plot or as stick diagram to show the time-varying dynamics of the process (panel b of Figure 7), or in statistical diagrams (panels c, d) which are commonly used for comparison of different data sets. A lot of routine workload is completed by these automated analysis and visualization tools, which accompany the data sets as dedicated methods. 5.3
Interactive map – Water level data
Figure 8 shows the contents of the tidal gage tab and presents another layer of the interactive map with access to water level data of a German Baltic Sea region. The visualization and analysis methods associated with these data are similar to those for wind. Plotting the time series for several locations (panel b) and analysis methods like FFT are available so far.
a) Map-based selection of tidal gaging stations
b) Plotting water level time series
Figure 8 Web services for water level data Reporting obligations of the Water Framework Directive and participation processes of Integrated Coastal Zone Management depend on reliable and efficient data analysis of distributed resources. Working environments as the one presented in Figures 7 and 8 achieve a standardized and integrated view on data, which also improves the quality of data products. The aims for the coming project years 2004-2008 are the implementation of the presented data handling methods according to ISO 19119 for web services, which means even more application of ISO 19115 metadata to secure interoperability of distributed resources in a common web portal.
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CONCLUSION
Standardized metadata help different user communities to find and share relevant and timely information from distributed data sources. Structured metadata describe contents, spatial and temporal coverage, quality and accessibility of data. This comprehensive documentation is suitable for automated search tools, and for quality assessment with analysis and visualization tools within the framework of ICZM. Online discovery and resource retrieval can only be efficient if data providers publish standardized metadata along with their data as a precondition for potential users to find, understand and share the data. The German project NOKIS depicts a successful bottom-up approach for a coastal metadata profile based on the ISO19115 metadata standard. It is applied in German Federal and State institutions charged with coastal responsibilities. Access routines to utilize discovered data are currently under development. The NOKIS metadata editor is a user-friendly and versatile tool to support the creation of metadata at distributed data archives for local application and for export to other information systems. XML-files export this information to a central repository, which can be searched through the NOKIS web portal http://nokis.baw.de. ACKNOWLEDGEMENTS The contributions to this paper were partially funded by the German Ministry of Education and Research BMBF through Research Center Jülich PTJ under grants 03KIS027 NOKIS and 03KIS049 NOKIS++. The authors gratefully acknowledge this support as well as the contributions from coworkers and other partners to these research projects. REFERENCES European Commission (1999). Lessons from the European Commission’s Demonstration Programme on Integrated Coastal Zone Management (ICZM). Retrieved January 15, 2004 from the European Commission http://europa.eu.int/comm/environment/iczm/vol2.pdf. European Petroleum Survey Group (2002). URL of Web site May 10, 2003: http://www.epsg.org/. European Parliament and the Council of the European Union (2000). Directive 2000/60/EC establishing a framework for the Community action in the field of water policy. Official Journal of the European Communities L327, 1-72. Federal Geographic Data Committee (2001). “Shoreline Metadata Profile”. Retrieved May 10, 2003, from FGDC Web site: http://www.csc.noaa.gov/metadata/sprofile.pdf. GDI-DE (2004).Geodateninfrastruktur Deutschland. URL of Web site January 10, 2004: http://www.imagi.de Getty Thesaurus of Geographic Names (2000). URL of Web site May 10, 2003: http://www.getty.edu/research/tools/vocabulary/tgn/index.html. Heidmann, C., Lehfeldt, R. (2004). “Information Infrastructure for ICZM Tasks”. In Liong, Phoon and Babovic (eds.) Proceedings 6th International Conference on Hydroinformatics, in press. ht://Dig Group (220) “How it works”. Retrieved May 10, 2003, from http://www.htdig.org/.
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International Standard Organization (2002). ISO 19115: Geographic information – Metadata. Draft International Standard. Retrieved May 10, 2003 from International Organization for Standardization http://www.iso.ch/iso/. International Standard Organization (2002). ISO 19119: Geographic information - Services. Draft International Standard. Retrieved May 10, 2003 from International Organization for Standardization http://www.iso.ch/iso/. Lehfeldt, R., Heidmann, C. (2003). “Information Infrastructure for Integrated Coastal Zone Management”. In Ganoulis, J., Prinos, P. (eds.) XXX IAHR Congress Proceedings. Theme A. Coastal Environment: Processes and Integrated Management, pp. 465-472. Lehfeldt, R., Heidmann, C., Piasecki, M. (2002). “Metadata in Coastal Information Systems”. In Holz, K.-P., Kawahara, M., Wang, S.S.Y. (eds.) Advances in Hydro-Science and –Engineering Volume 5. Proceedings of the 5th International Conference on Hydro-Science and Engineering, Warsaw. Abstract Volume p181. UDK (2004). The Environmental Data Catalogue UDK. URL of Web site January 10, 2004: http://www.udk-gein.de/en/index.sh University of Minnesota Map server (2003). URL of Web site January 10 2004; http://mapserver.gis.umn.edu/ UDK (2004). The Environmental Data Catalogue UDK. URL of Web site January 10, 2004: http://www.udk-gein.de/en/index.sh University of Minnesota Map server (2003). URL of Web site January 10 2004; http://mapserver.gis.umn.edu/
