The work in the ESDIN WP 11 ‘Interoperability Services’ had barely started when we were already faced with the first tough question: how we are going to make use of the services that the NMCAs are supposed to set up in the WP? The number of INSPIRE Download Services to be made available in the ESDIN project is still unknown, but might grow to be well over ten individual services.
There are now twelve European NMCAs involved in the WP 11 content access service development activity. As each INSPIRE theme can potentially be published via a dedicated service instance, depending on the organization of information in the backend systems, the number of individual service instances might easily become substantial. How an end user applications is then supposed to make use of the INSPIRE content in a meaningful way? There seems to be a need for supportive solutions for service integration.
In the INSPIRE context the issue of service integration seems to go mostly neglected. INSPIRE Directive actually raises the need for service integration in the Article 12 by introducing a notion of ‘technical possibility to link … spatial data sets and services to the network’. This statement has been further introduced in the Implementing Rule of each of the INSPIRE service type as an operation ‘Link X Service’. However, the concept is obscure and there is no idea about how this could be implemented in the concrete service interfaces. As this approach would most probably lead to cascading service stacks, the resulting effect on service performance might be undesirable.
One can distinguish several different categories of service integration. These include integration of services among a single service type, across service types, integration of services and content outside the traditional geospatial context, integration of content across thematic and spatial domains, and integration of core spatial services with supporting services like registries and GeoRM services. One of the most interesting and relevant problems is the integration of content in spatial domain, i.e. how one can achieve the end user experience of seamless content across national boundaries in Europe?
In the ESDIN WP 11 we have started to look at the challenge of service integration. A couple of approaches have been raised to tackle the issue, specifically focusing on Download Service and content integration in spatial domain. The proposed solutions rely either on the use of dedicated clients, cascading services with caching capabilities, centralized gateways applying harvesting schemes or higher-level service APIs. As the first ESDIN Download Services start to pop up (we have currently eight of them) the needs and chances to test various service integration approaches are arising. I look forward to see interesting solutions proposed and tested in the ESDIN WP 11 over the coming months.
Lassi Lehto
WP 11 lead