Development of an ISO compliant, internet-based metadata editor for

Development of an ISO compliant, internet-based metadata editor for the EU project MEDIS Marion WILDE, Hardy PUNDT

Summary Within the project MEDIS a metadata server as well as an Internet atlas have been prototypically developed and are currently being tested. The atlas is aimed at the provision of spatial and socio-economic data from specific test areas on five Mediterranean islands, while the metadata server is intended to give detailed information about the atlas data. The project partners were asked to provide metadata based on a profile that meets the ISO metadata standard for spatial information as well as specific needs within MEDIS. This paper concerns the requirements, collection, and characteristics of metadata and the development of a metadata editor, compared to existing developments. The editor is provided to the project partners, but could be used by many other data providing institutions, when a revision based on the results of the current tests has been carried out.

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MEDIS – Aim and methodology

The project MEDIS - towards sustainable water use on Mediterranean islands (MEDIS 2002), funded by the European Commission, is concerned with the availability and usage of water on Mediterranean islands. The quantity as well as the quality of water cause various problems in these areas. This is due to several reasons, e.g. the numerous competing uses like agriculture and tourism, the over-use of existing aquifers and a partly inadequate water management. Additionally, islands face a special problem that arises from their isolated position and, associated to that, the risk of sea water intrusion. As a lot of these problems are common to all islands in the Mediterranean, the application of common concepts and methods to solve them seems to be reasonable. Accordingly, the overall goal of MEDIS is the development of recommendations for a sustainable water management on Mediterranean islands, based on a comprehensive analysis of natural and socio-economic data. Twelve institutes from seven countries are working on analyses and investigations that concern the specific situations on Mallorca, Corsica, Sicily, Crete and Cyprus. In a first step, data from various areas such as geography, hydrology, agriculture, tourism and socioeconomy are collected. They give a comprehensive insight into supply and demand of water on the islands. Based on this information, recommendations for water management are drafted within MEDIS. An important step follows with the intensive discussion and eventually the revision of the recommendations in close cooperation with local stakeholders. Legal conditions are taken into account to ensure the applicability of the proposed recommendations. Finally, a main outcome of the project will be recommendations that support a sustainable water management, applicable on the participating islands. Such recommendations must be conformant with national and

Marion Wilde, Hardy Pundt

European laws and guidelines (e.g. Water Framework Directive (EC 2000)) and with the specific requirements of the local stakeholders. The acquisition of data that are suitable to support the derivation of recommendations is difficult on the different islands, due to reasons of data ownership and lacking administration. Public presentation of the data that can be acquired or purchased within MEDIS is thus even more important. Hence, the development of an Internet atlas with a corresponding metadata server is one of MEDIS’ sub goals. The maps will support the conclusions that are based on a comprehensive knowledge of the natural and socioeconomic conditions. For the implementation of the atlas, ESRI© ArcIMS is used. Currently, the atlas exists as a test version. One advantage of ArcIMS is the metadata service which enables publication of metadata via the Internet. Metadata can be XML documents produced with the help of ArcCatalog, but any other XML document as well. Metadata services are used in MEDIS to facilitate search for geodata collected during the project. ArcCatalog, however, cannot be used within MEDIS, simply because the software is not available to most of the partners. As a consequence, another solution for the collection of metadata had to be found for the MEDIS purposes. This resulted in the development of a metadata editor.

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The metadata editor

MEDIS aims at conformance with the International Standard for geographic metadata, ISO 19115 (ISO 2003), to ensure homogeneity and exchangeability of metadata. ISO 19115 defines more than 300 elements for describing geographic datasets. To be conformant with the standard, the core elements determined by ISO are a minimal requirement. A metadata profile was developed within MEDIS that contains some metadata elements besides the core (Wilde et al. 2003). A collaboration between the two EU projects MEDIS and BALANCE (BALANCE 2003; Bernard et al. 2003) was profitable while developing the profile. For the acquisition of metadata according to the profile an editor for the MEDIS project was designed and prototypically implemented.

3.1 Requirements of the MEDIS metadata editor The editor is supposed to enable the acquisition of metadata according to the ISO conformant MEDIS profile. An additional requirement is the validation of each metadata document and the subsequent notification of the originator. Hence, each metadata set shall be stored in an XML document. One reason for this is to permit integration into the ArcIMS digital atlas as described above. Furthermore, XML metadata documents can be validated against the implementation schema which is defined in ISO 19139, the future implementation standard for ISO 19115 (ISO 2002a). This document contains a UML implementation model and an XML Schema that is derived from the model. The schema can be found on the homepage of the Digital Geographic Information Working Group (DGIWG 2003a;b). Additional schemata are available at this site that are required for the

ISO compliant internet based metadata editor

implementation of ISO 19115. They describe for example data types from ISO 19103 (ISO 2001) or ISO 19108 (ISO 2002c). Whenever possible, false entries shall be prevented by using selection lists or menus for pre-defined values: ISO 19115 defines a lot of such code lists, e.g. for the elements topic category or legal constraints. It is planned to enable the access to the editor for all project partners via the Internet. This makes local installation dispensable. For updating purposes, the centrally stored XML documents must be accessible to the originators. Such an access is furthermore useful because the contents of a lot of metadata elements can be expected to be identical for different datasets (e.g. reference system). When having access to existing metadata documents, they can be copied and only such values have to be changed that have identified to be not equal. For access management, the definition of user profiles is necessary to ensure that the partners have only access to those metadata documents which they produced themselves.

3.2 Existing metadata editors As far as we know there is currently no commercial product that enables the acquisition of metadata according to the complete ISO 19115 standard, and profiles derived from it. This may be due to the fact that the standard has been established quite recently (May 2003). Another problem occurs through such elements and data types in profiles (which’s use is explicitly intended by ISO (ISO 2002b;2003)) that come from other ISO standards or are self-defined. Such elements can hardly be expected to be found in a standard user interface. ESRI© ArcCatalog contains a metadata editor with two different templates. One of such templates enables the acquisition of metadata according to FGDC (FGDC 1998), the other is an "ISO editor". However, the preset editor contains only the core elements. Apart from such commercial products there are some other editors, mostly developed in research projects. One example is described in (Zarazaga-Soria et al. 2003) who developed a Java tool for the creation of ISO/FGDC metadata that is being tested in several Spanish institutions. This tool does not contain the entire standard. The GUI and functionality of this editor cannot be adjusted to specific metadata profiles. Another example is described in (Kazakos et al. 2003; Kazakos et al. 2002). However, none of the editors covers the requirements of the MEDIS project completely.

3.3 Characteristics of the MEDIS metadata editor For the implementation of the editor the web programming language PHP is used. The editor is accessible to all project partners via the Internet. When submitting the forms, an XML document is created from the entries and saved on the server (one document per metadata set). The XML metadata document and the corresponding geodata sets are named equally to facilitate allocation and administration.

Marion Wilde, Hardy Pundt

Figure 1: Screenshots of editor mask and the resulting XML document (both excerpt)

ISO compliant internet based metadata editor

Figure 1 shows a section of the editor mask and an excerpt of the resulting XML document that contains exemplary metadata according to the MEDIS profile and the implementation schema. As can be seen, the order of the fields in the editor mask does not necessarily correspond with the order of elements in the XML document. During the development it became obvious that some elements that are connected thematically do not appear in such a connected way in the XML Schema. For usability reasons we had to diverge slightly from the given structure when designing the GUI to query related elements in one step. When submitting the forms, these entries are brought back into the "original" structure of the XML Schema. The GUI is dynamically adjusted when one element is needed more then one time. For grid data the number of axes is given first, then the characteristics of each axis are specified. In the GUI, the fields for the axis characteristics are shown as many times as the number of axes that has been indicated before. This is shown in figure 2.

Figure 2: Axes description for grid data (screenshot) There are several elements which’s values appear to be equal for all data sets or that are pre-defined in the profile as being equal. An example is the language of the metadata set (English), or the name and version of the standard used. To save efforts for each originator, such pre-defined elements are implemented as hidden fields. They are not visible for the originator and are directly incorporated into the XML document.

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Outlook

The editor is still under construction. The draft version presented here is currently being tested by the project partners (April 2004). Within this version, the editor covers many of the requirements mentioned before: ?? ?? ?? ??

conformance with the MEDIS metadata profile and the ISO requirements availability via the Internet easy entries through use of selection lists and menus storage as XML document

Marion Wilde, Hardy Pundt

The next step is to validate the schema. Furthermore, the use of profiles will be implemented. Some improvements concerning various aspects, such as the user interface and MEDIS specific metadata, are necessary to optimise the usability of the editor. Reactions from the project partners during the test phase are of high interest for the collection of suggestions to improve the editor. Currently the aim is to provide an editor that meets the specific MEDIS requirements. Due to the fact that customisation of the editor is relatively easy to realise, the tool could be used in many other projects or institutions where metadata are collected to support dataset identification and data exchange. The mentioned numerous, but isolated solutions show that there is obviously a need for such tools. The need for metadata will increase taking into account the increasing provision of spatial data through the Internet, where human users as well as software agents are searching for spatial information. As a further step, we consider the development of a ISO conformant metadata editor that is dynamically adjustable to the respective requirements or profiles of specific users. Such a tool must also allow the integration of self-defined metadata elements.

Acknowledgement The authors thank Carsten Kessler and Krzysztof Janowicz for their support during the design and implementation phases of the metadata editor. The work is supported by the European Commission in the framework of the MEDIS project [EVK1-CT-2001-00092].

References BALANCE (2003): Global Change Vulnerabilities in the Barents Region: Linking Arctic Natural Resources, Climate Change and Economies: http://www.balance-eu.info Bernard, L.; N. Ostländer and C. Rinner (2003): Impact Assessment for the Barent Sea Region: A Geodata Infrastructure Approach, in: Gould, M., Laurini, R., Coulondre, S. [eds.]: 6th AGILE Conference on Geographic Information Science, April 24-26 in Lyon, France: 653-661. DGIWG (2003a): ISO 19139 Dataset Implementation Model and Schema (Version 0.8): Digital Geographic Information Working Group, http://metadata.dgiwg.org/ISO19115/ISO19139_v0_8.htm DGIWG (2003b): Metadata Development Efforts: Digital Geographic Information Working Group, http://metadata.dgiwg.org/index.htm EC (2000): Directive 2000/60/EC of the European Parliament and of the Council of 23 Oct 2000 establishing a framework for Community action in the field of water policy ESRI (2002): White Paper: ArcIMS 4. Creating and Using Metadata Services FGDC (1998): Content Standard for Digital Geospatial Metadata. FGDC-STD-001-1998 ISO (2001): Geographic Information - Conceptual schema language (19103, N1082) ISO (2002a): Geographic Information - Metadata - Implementation Specification (19139, New Work Item Proposal) ISO (2002b): Geographic Information - Profiles (19106, Draft International Standard DIS) ISO (2002c): Geographic Information - Temporal Schema (19108, Final Draft International Standard FDIS)

ISO compliant internet based metadata editor

ISO (2003): Geographic Information - Metadata (19115, International Standard IS) Kazakos, W.; A. Akhounov; H. Paoli et al. (2003): Editing ISO 19115 Compliant Metadata in EUROSION, in: Gnauck, Albrecht and Ralph Heinrichs [eds.]: 17th International Conference Informatics for Environmental Protection (EnviroInfo): The Information Society and Enlargement of the European Union: 468-474. Kazakos, W.; A. Valikov; A. Schmidt et al. (2002): Automation of Metadata Repository Development with XML Schema., in: Pilmann, Werner and Klaus Tochtermann [eds.]: 16th International Conference Informatics for Environmental Protection (EnviroInfo): Environmental Communication in the Information Society: 400-407. MEDIS (2002): Towards sustainable water use on Mediterranean Islands: addressing conflicting demands and varying hydrological, social and economic conditions: http://www.uni-muenster.de/Umweltforschung/medis/index.html Wilde, M.; M. Lange; H. Pundt, N. Ostländer, K. Janowicz (2003): An environmental metadata profile for the EU project MEDIS, in: Gnauck, A. and R. Heinrichs [eds.]: 17th International Conference Informatics for Environmental Protection (EnviroInfo): The Information Society and Enlargement of the European Union: 482-489. Zarazaga-Soria, F. J.; J. Lacasta; J. Nogueras-Iso et al. (2003): A Java Tool for Creating ISO/FGDC Geographic Metadata, in: Bernard, L.; A. Sliwinski und K. Senkler [eds.]: Geodaten- und Geodienste-Infrastrukturen - von der Forschung zur praktischen Anwendung. Beiträge zu den Münsteraner GI-Tagen. IfGIprints 18: 17-30.