OGC, INSPIRE, and Metadata
Metadata is critical for geospatial resource discovery, determination of fitness for purpose, and more. The value of metadata lies in the structure and meaning that it provides. Metadata serves asset discovery by identifying assets and allowing them to be found by relevant criteria. Metadata also brings similar assets together and distinguishes dissimilar assets. Value is added to data and service holdings. Standards for the creation and use of metadata have a long history in the OGC, as well as many ongoing SDI activities such as INSPIRE and the US Geoplatform Activity.
This is why a key OGC CDB Standards Working Group (SWG) activity is enhancing the OGC CDB standard to define requirements and practices for metadata. CDB version 1.0 does not provide any guidance on the use of metadata as used in the geospatial community. These metadata enhancements are planned for CDB version 1.1. As part of this activity, the SWG investigated a number of metadata standards used in the geospatial community. Major metadata activities such as those in INSPIRE were also evaluated. The review of the INSPIRE Metadata Technical Guidance and related documents led me to write this blog.
The investigation of INSPIRE metadata requirements and related technical guidance was very educational but not easy. A fairly large number of documents need to be read and understood in order to implement metadata that’s compliant with the INSPIRE technical guidance.
Article 5 sub-clause 1 of the INSPIRE Directive states, “Member States shall ensure that metadata are created for the spatial data sets and services corresponding to the themes listed in Annexes I, II and III, and that those metadata are kept up to date.” The directive does not define what metadata standard or related technologies to use. The Directive states basic requirements. The implementing guidance is provided in a separate, very detailed document INSPIRE Metadata Implementing Rules: Technical Guidelines based on EN ISO 19115 and EN ISO 19119. This document specifies the requirements for implementing INSPIRE compliant metadata based on various ISO standards, specifically 19115:2005 and 19119:2005. This guidance defines which elements are mandatory and which are conditional or optional. Other documents provide additional technical guidance. There are also metadata validation and compliance policies and related tools.
In addition to the INSPIRE metadata mandate and guidance, governments in the EU also need to comply with the requirement to achieve cross portal metadata interoperability. This requirement states that metadata provided and/or used in an INSPIRE compliant geoportal must interoperate with metadata from other eGovernment portals. The eGovernment portals use a European Union de-facto standard called DCAT-AP. DCAT-AP was developed as part of the EU Programme Interoperability solutions for public administrations, businesses and citizens (ISA²) “with the purpose of defining a cross-domain metadata interchange format that can be used to share dataset metadata across data catalogues operated across the EU.”
Within this context, under the EU ISA Program, and taking into account the INSPIRE metadata profile and relevant ISO standards on which it is based, the community developed a geospatial profile of DCAT-AP: GeoDCAT-AP. The work was coordinated by a Working Group with representatives from the EU Member States led by JRC. The profile has been endorsed by the Member States through the ISA SIS Group / Coordination Group / TIE Cluster where Member States ‘adopt’ e-Government solutions. There is no legislation as is the case for INSPIRE.
GeoDCAT-AP is specifically designed to enable the sharing of geospatial metadata, in particular those available via the INSPIRE infrastructure. GeoDCAT-AP defines mappings from ISO 19115 (the ISO standard for geospatial metadata) to DCAT-AP and other general-purpose RDF vocabularies. The GeoDCAT-AP work included the development of an API. This API provides the ability able to transform on the fly ISO 19139 records into DCAT-AP or GeoDCAT-AP. ISO 19139 defines an XML-based implementation of ISO 19115. Please note that the GeoDCAT-AP specification does not replace the INSPIRE Metadata Regulation nor the INSPIRE Metadata technical guidelines based on ISO 19115 and ISO19119. The purpose of GeoDCAT-AP is to give owners of geospatial metadata the possibility to achieve more visibility by providing an additional RDF syntax binding. Of course, at least to me, this raises the question of whether the current INSPIRE Metadata guidance and related policy directives need to evolve to meet market and user needs.
What does all this mean?
The INSPIRE metadata requirements were originally specified in the mid-2000s and the technical guidance originally published in 2007 and the implementing rules published in 2008. Ten years is an eternity in IT. Since then, there has been a tremendous move to using web technologies for discovery, linking, and access to information resources. Issues, such as the metadata technical guidance being XML based, need to be addressed. The Web world is moving away from XML to other technologies such as JSON and RDF. Today’s users want to use search engines to express queries and discover ‘fit for purpose’ spatial data. More and more users want applications that easily link data resources and enable rapid discovery traversal of these resources. At the end of the day, users are recognizing the need for a web of spatial resources. However, as stated in the W3C Data on the Web Best Practices Recommendation: “The openness and flexibility of the Web creates new challenges for data publishers and data consumers, such as how to represent, describe and make data available in a way that it will be easy to find and to understand.”
There is a tension within the INSPIRE community. Much of the tension is a response to the market and user forcing functions. Another factor is a desire for more simple approaches that reduce the complexity and costs of the current in force technical guidance and related compliance requirements. In some ways, INSPIRE is facing the same technology life cycle and evolution challenges that any software company has to deal with: how does one move forward to capitalize on better technologies and user experience without destroying investments in existing infrastructure and knowledge base?
This is not just an INSPIRE issue. This is a geospatial industry wide issue (although INSPIRE has the additional challenge of EU legislation and compliance requirements). As an industry wide issue, we need to work collaboratively to make sure that current and future requirements for metadata and spatial resource discovery are addressed. In recognition of this need, over the last few years the synergies between the INSPIRE community, the OGC, and the W3C have increased. Evidence of this collaboration is the joint W3C/OGC Spatial Data on the Web Working Group, increasing DCAT and DCAT-AP discussions in the OGC, and the INSPIRE ‘What If’ sessions at the 2017 Delft OGC meeting and this September’s INSPIRE Conference. These collaborative efforts need to not just continue but to expand. The long-term success of INSPIRE and other SDI activities rest on our ability to identify and document standards and best practices that enable the agility and flexibility to meet the ever-changing landscape of policy, user needs, and technology.