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Metadata Watch Report #3

[ contents | section 1 | section 2 | section 3 | section 4 | section 6 ]

Section 5 - Domain reports

5.1 Industry sector
5.2 Publishing sector
5.3 Audio-visual sector
5.4 Cultural Heritage sector
5.5 Educational sector
5.6 Academic sector
5.7 Geographical information sector

5.7 Geographical information sector

Correspondent: Elise Sfeir, PricewaterhouseCoopers

5.7.1 Introduction

This brief introduction highlights the main standards that are used by major GI projects that are identified in the present report. Actually, many GI initiatives look at these main standards and use some of them to create their metadata application profiles. It is important to note that in the GI world, the FGDC which is an American committee has a lot of impact on the standards used and on the developments of metadata. All the other initiatives have had to do with the FGDC. The exception to these standards seems to be Dublin Core. The GI world does not use it very much and the FGDC, for the moment, does not really recommend Dublin Core for GI metadata.

Therefore, many initiatives do not look at Dublin Core. They only consider one standard and follow it, or they make their own standard. Yet, some European projects, such as ETeMII do not fully follow the FGDC and look at the DCMI. ETeMII, which aims at organising a network of excellence, bringing together most of the stakeholders of the Territorial Management Information market, coming from research, industry and public sector, liaise with Dublin Core. ETeMII will liaise with various groups in order to built its own application profiles maily by mapping Dublin Core and ISO/ TC 211 - 19115. The Madame project also recommends and follows this mapping.

5.7.2 Standards

ISO/TC 211 - 19115

In 1994 the International Standards Organisation created technical committee 211 (ISO/ TC 211 - 19115) with responsibility for Geoinformation/Geomatics. They are also preparing a family of standards; this process involves a working group, a committee draft, a draft international standard and finally the international standard. ISO have now released the committee draft of 'ISO 15046-15 - GI - Metadata'. CEN/ TC 287 has liaison status with ISO/ TC 211 - 19115 which means the results of the work in Europe will be taken into account when developing the global standards.

The ISO standards on geographic information ISO/ TC 211 - 19115 can be found on: http://www.standardsinaction.org/gismetadata/

In 1992 the Comité Européen de Normalisation (CEN) created technical committee 287 with responsibility for geographic information standards. A family of European Prestandards have now been adopted including 'ENV (Euro-Norme Voluntaire) 12657 Geographic information - Data description - Metadata'.

In the USA the Federal Geographic Data Committee (FGDC) approved their Content Standard for Digital Geospatial Metadata in 1994. This is a national spatial metadata standard developed to support the development of the National Spatial Data Infrastructure. The standard has also been implemented outside of the USA, for example for the South African Spatial Data Discovery Facility.

The OpenGIS Consortium (OGC) is an international membership organisation engaged in a cooperative effort to create open computing specifications in the area of geoprocessing. As part of its draft 'OpenGIS Abstract Specification' OGC has a topic on recording metadata for spatial data. OGC are working closely with FGDC and ISO/ TC 211 - 19115 to develop formal, global spatial metadata standards. At their plenary meeting in Vienna, Austria in March 1999, ISO/ TC 211 - 19115 welcomed the satisfactory completion of the co-operative agreement between the OpenGIS Consortium and ISO/TC 211 and endorsed the terms of reference for an ISO/ TC 211 - 19115 / OGC co-ordination group.

The FGDC is a very important and international initiative. It has developped its own metadata standards which has actually a lot of impact on the other metadata standards developments.

The FGDC Metadata Standard is being harmonised with the International Organisation for Standardisation (ISO) Technical Committee (TC)211 Metadata Standard 19115. The June 8, 1994 FGDC Metadata Standard was used as the base document for International Organization for Standardization (ISO) 15046 Part 15.

The FGDC developped the Content Standard for Digital Geospatial Metadata (CSDGM) which objectives are to provide a common set of terminology and definitions for the documentation of digital geospatial data. The standard establishes the names of data elements and compound elements (groups of data elements) to be used for these purposes, the definitions of these compound elements and data elements, and information about the values that are to be provided for the data elements.

The development of this standard is related to the Spatial Data Transfer Standard (SDTS) that was developed to allow the transfer of digital spatial data sets between spatial data software.

The Content Standard for Digital Geospatial Metadata uses to the maximum extent possible, existing International or National Standards, as documented in Office of Management and Budget Circular A-119 "Federal Participation in the Development and Use of Voluntary Consensus Standards and in Conformity assessment Activities." American National Standards referenced in the Content Standard for Digital Geospatial Metadata include the American National Standards Institute, 1975, Representations of universal time, local time differentials, and United States time zone reference for information interchange (ANSI X3.51-1975): New York, American National Standards Institute; American National Standards Institute, 1986, Representation for calendar date and ordinal date for information interchange (ANSI X3.30-1985): New York, American National Standards Institute; American National Standards Institute, 1986, Representations of local time of day for information interchange (ANSI X3.43-1986): New York, American National Standards Institute.

The FGDC has 220 elements composed of compound elements and data elements.

The FGDC proposes some guidelines to create application profiles based on the FGDC metadata standards. The information below has been taken from a very useful document Guidelines for Creating a Profile for the Content Standard for Digital Geospatial Metadata, that can be downloaded from the following Web site: http://www.fgdc.gov/metadata/csdgm/profile.html

The current Content Standard for Digital Geospatial Metadata provides metadata collectors with formally defined elements known as standard elements. The metadata Standard attempts to standardize the content of metadata elements for a wide range of digital geospatial data. However, some users may determine that modifications to the Standard are needed to create meaningful metadata for their data sets. The Standard allows the user to create extended elements and profiles. Extended elements are user-defined elements outside the Standard needed by the metadata producer. A profile is a document that describes the application of the Standard to a specific user community.

Profiles may be formalized through the FGDC standards process or may be used informally by a user community. FGDC is the approval authority for profiles. To become recognized by the FGDC, a metadata profile must go through the FGDC standards review and approval process. FGDC approved profiles must specify a maintenance authority. While the FGDC is the designated maintenance authority for the Metadata Standard the organization or agency sponsoring a profile will be considered the maintenance authority for that profile.

5.7.4 ANZLIC, the Australia New Zealand Land Information Council

ANZLIC's mission is to provide leadership for effective management and use of land and geographic information to support economic growth, and the social and environmental interests of Australia and New Zealand. Key objectives under the headings: data; infrastructure; standards; access; industry development and organisational framework, are the focus of efforts to provide this leadership.

A Working Group was formed by the ANZLIC Advisory Committee in April 1995 to work on the following tasks to improve community access to data:

• produce a Metadata Framework paper which identifies and defines the mandatory metadata elements of a national land and geographic data directory system, discussing creation, maintenance and directory custodianship issues;
• using the Metadata Framework paper, promote the concept of a national data directory system to help determine the priorities and issues for implementing a national directory;
• develop an implementation plan for a national data directory system, including procedures for transfer of metadata between jurisdictions and the national directory system;
• develop and circulate for comment, a discussion paper on national guidelines for developing land and geographic data quality, in a form suitable for developing into an Australia/New Zealand standard.

The ANZLIC guidelines have been developed to promote a consistent standard of description for this small number of core metadata elements, that are generally common for all types of data and designed to indicate what data exists, its content, geographic extent, how useful it might be for other purposes and where more information about the data can be obtained. The purpose is to make information about all available data freely available so that existing data can be reused for other purposes if it is suitable, reducing the duplication of effort.

ANZLIC can be actually considered as a standard on its own because it can be compared to the FGDC work and mainly the ISO/ TC 211 - 19115 which has had extensive Australian input, particularly from interests associated with ANZLIC.

The US approach, developed by the Federal Geographic Data Committee (FGDC), specifies the structure and expected content of some 220 items (elements) which are intended to describe digital geospatial datasets adequately for all purposes. The ANZLIC approach is deliberately less ambitious than what has been attempted in the US. Arguments advanced in support of the more modest objective rely on experience to date with the creation of high-level directories in Australia.

While ANZLIC has not adopted the US approach, the Australia New Zealand framework is, as far as possible, consistent with the guidelines on Digital Geospatial Metadata produced by the US FGDC and with the Australia New Zealand Standard on Spatial Data Transfer AS/NZS 4270. The reasons for this are:

• many organisations are already using these standards for their data management activities;
• some vendors of software are providing templates and other support to the implementation of the standards; and,
• these standards are being implemented in some discipline or theme areas where there is international exchange of metadata.

However, until now, there has been no unifying set of metadata elements that could be used as the basis for the development of national metadata standards. ISO/ TC 211 - 19115 will provide this unifying set of metadata elements.

ANZLIC have based it on the FGDC work and then they have made their own core elements and categories without taken them from another developed standard. They did not proceed to any mapping and comparison with another namespace.

There are 32 ANZLIC core metadata elements that are grouped in 9 categories.

To assist with the implementation, ANZLIC has developed a run-time software tool to support the collection of metadata and to ensure consistent description of core metadata elements. This software tool, based on Microsoft Access, is available for use by dataset custodians throughout Australia and New Zealand.

The Data Entry tool may be used within organisations to manage the metadata database.

5.7.5 The National Geospatial Data Framework (NGDF)

All the following information has been taken from very interesting documents untitled Discovery Metadata Guidelines and Discovery Metadata Transfer Format and Communications Protocol Guidelines that can be downloaded on the following web site: http://www.ngdf.org.uk/

The NGDF has developped guidelines on metadata standards indicating their choices of namespaces and how they use various standards in order to built their application profiles.

This NGDF document represents the first stage in the development of metadata services for the discovery of data resources that have a geographic component. The aim is to provide a consistent and simple method of documenting any data resources that are referenced in some way to the earth's surface whether by coordinates or geographic identifiers (addresses, administrative area, postcode area). The consistent recording of metadata or information about data resources and their presentation in catalogues accessible to the user community via the Internet considerably facilitates the discovery of such data resources.

There are a number of metadata standards in existence or under development. None of those existing were found to meet with the requirements of being simple and applicable to the full range of data resources that are geospatially referenced. In developing these NGDF Guidelines metadata standards which are not specifically for geospatial data such as the "Dublin Core" have also been examined.

These metadata standards have been produced for use in the United Kingdom. However, with the evolution of global information infrastructures, developments outside the UK cannot be ignored. Therefore the Guidelines must be regarded as interim pending the development of standards at the international level such as those being developed by Technical Committee 211 of the International Organisation for Standardisation (ISO).

The principals standards that the NGDF looked at for their application profiles are:

• Draft ISO Standard 15046-15 Geographic Information - Metadata
• European Standard prEN 287009

They took also in consideration the work of the United States Federal Geographic Data Committee (FGDC) that has developed a standard known as the Content Standard for Digital Geospatial Metadata and that has strong parallels with the draft ISO standard. A further initiative driven by the Open GIS Consortium (OGC) was also looked at.

The NGDF Guidelines that are provided are an interim solution pending the final release of the ISO, FGDC and OGC standards. It is actually hoped that these standards will converge, indeed the ISO, FGDC and OGC standards already have a great deal in common.

The definitions of NGDF are closely allied to the draft ISO standard. It is anticipated by the Working Group that these Guidelines will remain unaltered until the publication of the ISO standard in 2000 at which time it will be modified to match the ISO standard or possibly become a profile of the ISO standard.

The NGDF guidelines are based upon the draft ISO metadata standard 15046-15. The intention is to make the guidelines a profile of the ISO standard in time. They were produced after extensive research of existing standards and guidelines and following a workshop in which data producers were encouraged to compile metadata relating to their own datasets.

Some 42 metadata elements have been identified as necessary for documentation at the discovery level of which 16 are mandatory and a further 7 are conditional depending on the context, the remainder are optional. These elements cover title, theme, date and spatial extent, access constraints, nature of the resource, how to obtain additional information and data supply.

Finally, the "NGDF Profile" is actually a subset of the GEO profile developped by the FGDC. Although only a subset of full Z39.50 functionality, the GEO profile is over large for NGDF Discovery Metadata requirements. There are a few NGDF metadata attributes (i.e. Status of Start Date of Capture and Status of End Date of Capture, Alternative Title and level of Spatial Detail) that cannot be supported as there is no appropriate mapping to the GEO attribute sets. Until an NGDF Profile is defined these optional attributes will be excluded from the protocol.

5.7.6 ESMI, the European Spatial Metadata Infrastructure

The following information have been derived from the ESMI Web site: http://esmi.geodan.nl/uk/standards.html

ESMI has established a core metadataset much like the Dublin Core but based on the existing standards CEN, ISO and FGDC. As ESMI is aiming to specify a minimum set of descriptions to meet the needs of professional GIS users they have limited the mandatory fields to a minimum. Therefore, the core consists of a set of elements that are required, however some of these do not have to contain a meaningfull content (content optional) as opposed to the content mandatory fields. This set was a technical requirements because the query interface needs to be able to query the various connected database for this core set of metadata elements. It is the responsibility of the data provider to be more specific and provide the best possible meta information.

ESMI proposes a metadata implementation based on existing standards that enable compliant metadata services to be searched over the Internet. Users of spatial data will be able to easily locate spatial data resources. To be compliant metadata services will need to make certain metadata fields accessible to the ESMI searching mechanism. The minimum set of metadata fields is the ESMI core metadata.

ESMI applies the CEN/TC 287 metadata standard. This is the metadata standard used in the ESMI project because many of the existing metadata services in Europe are based on the work of CEN/TC 287 and the standard will not change in the next two years. In 1992 the Comité Européen de Normalisation (CEN) created technical committee 287 with responsibility for geographic information standards. A family of European Prestandards have now been adopted including 'ENV (Euro-Norme Voluntaire) 12657 Geographic information - Data description - Metadata'.

Furthermore, the on-going work of ISO/ TC 211 will be considered during the work of ESMI to ensure as much compatibility as possible.

The following information has been based on http://esmi.geodan.nl/uk/mapping.html, where a document deals with core metadata, search profile and procedures for managing semantics. The ESMI core metadata and search profile together with the controlled lists and definitions of technical terms have been agreed upon during a technical meeting to be used in this form for the first ESMI prototype.

There are 9 main metadata elements, composed by sub-element, recommended by ESMI and based on the CEN/TC 287 standard, (i.e. metadata element: dataset identification has 2 sub-elements: dataset title and abbreviated title). They represent the minimum selection of metadata elements needed for a provider to obtain ESMI certification. Other providers may also be accepted with other conditions. The elements of the core metadata as well as the recommended further metadata should be provided fully multilingual.

The necessary metadata elements for ESMI are separated into 'content mandatory' (CM) and 'content optional' (CO). Content mandatory - metadata elements that have to be provided through the server software and which MUST contain information. Only a limited number of metadata elements is classified as CM. Content optional - metadata elements that also have to be provided through the server software but are NOT required to have a 'real' content ('not available' is allowed).

ESMI has also some controlled lists for the thesaurus. Language translations of the keywords of the controlled lists are provided as well. The controlled lists apply for the following elements:

• Language
• Overall positional accuracy
• Datum
• Ellipsoid
• Map projection
• Vertical Datum
• Term
• Restrictions on use
• Price information
• Organisation role
• Point of contact role
• Formats

Regarding the semantics, a next phase is going to start using thematics thesaury that data providers can map to their own thesaurus, in this way users looking for data can create a query using the correct terms that are mapped to the terms of the local implementation.

The search interface, the most important issue for managing semantics is managing the issue of having different administrative boundaries and hierarchies. In ESMI, this issue will be solved by using MEGRIN's SABE file (Seamless Administrative Boundaries of Europe). SABE contains high quality data from 26 different national producers, which have been made homogeneous and form a unique and consistent product. SABE presents several features which make it unique. It is homogeneous, enabling the user to work across borders without incurring the risk of semantic variations on either side. Although it is derived from source data protected by copyright in each country of origin, agreements have been signed between MEGRIN and each NMA to allow the marketing of all or part of SABE on the basis of a single ©MEGRIN licence. This simplification greatly helps user access. SABE is also regularly updated. To address the semantic issue within SABE itself, MEGRIN uses for the countries of the European Union the official NUTS nomenclature (Nomenclature of Statistical Territorial Units) and SABE presents it up to the NUTS 5 level ("the smallest administrative unit with its own elected assembly", i.e. the "commune" in France, or "ward" in England, ...).

In Appendix C, the application profiles of FGDC, ANZLIC, NGDF and ESMI are described.

[ contents | section 1 | section 2 | section 3 | section 4 | section 6 ]

Maintained by: UK Office for Library and Information Networking (UKOLN)
Last updated: 07 August 2001