SNS focuses on the provision of Web Services so that Environmental Portals and related applications may benefit from semantic methods without having to develop them by themselves. Further more such services ensure that all these applications are referring to a shared terminology. This is a major building block for any kind of information integration.
SNS provides three basic services and some composite services. The following short descriptions of each service provide clickable names that will lead you to a dedicated Web form. These forms are intended for a first interactive Service tryout.
Basic Services
SNS Basic Services support searching the terminology as well as direct access to a term with all its known properties and associations.
getPSI:
Direct term access by ID. PSI is short for "Published Subjects Indicators" (OASIS). Each term of a controlled vocabulary should be represented by a unique and resolvable URL and by this be persistently "published". This Service returns all properties (labels, description, source, etc.) as well as its direct associations to further terms of the vocabulary. Expressing a getPSI request in the form of a single URL (see below) serves ideally as a resolvable term reference within any kind of metadata.
findTopics:
Search for topics by terms. These may be names for concepts or just occur in descriptions or other attributes. Topic names in SNS need not to be unique (homographs), and they can be composed from several words. Within the Thesaurus the flexion of the names is also known. The request supports many refined optional parameters. The results also contain the unique Topic ID which is needed for the getPSI request.
findEvents:
this is a specialisation of findTopics dedicated for searching the chronicle. Temporal conditions may be added as a search condition.
Composite Services
SNS Composite Services are built from Basic Services, ready for use in more complex tasks:
anniversary:
What happened X years ago? Pass any arbitrary date to this request. The response prefers the exact date.
If no exact match is available, the response delivers anniversaries (25, 50, 100).
getSimilarTerms:
Identifies terms from the environmental thesaurus that are similar to a source term by meaning (not by spelling). Typical use cases may be suggestions for a full text search or the word choice while writing documents.
getHierarchy:
starting with a given term from the thesaurus this request returns the term hierarchy (broader/narrower). Results may be directed "upwards" or "downwards" or restricted to a given depths. Due to the structure of the available vocabulary, this service is only applicable to thesaurus descriptors in German language today.
autoClassify This service takes any kind of text and identifies significant keywords from the controlled vocabulary using a fully automated text analysis. You may pass the text either directly as a request parameter or indirectly in form of a URL which will be resolved and parsed by the service.
Technical Access to the Services
SNS supports two kinds of technical access:
Access by a single URL with query-string-encoding of all parameters (http GET).
Access by Web Services with SOAP binding and a formal service description in the WebService Description Language (WSDL) format.
The Web forms provided with the short descriptions above only support the most frequently used options of the request parameters. A complete technical description of all services for both access modes can be downloaded:
For using the SNS Web Services you need an access key. Your registration will be verified by the Federal Environment Agency. A commercial usage of SNS services is currently not supported.
If you want to access SNS Web Services using the SOAP binding you may download ready-for-use Java or .NET stubs. These packages also contain a little sample application.
SNS conforms to the ISO Standard 13250 Topic
Maps. This has been decided in an early stage of development (2001) when the W3C Semantic Web Activity just had been established. Compared to the maturity state of the Resource Description Framework (RDF) at that time, Topic Maps have been the superior match with regard to the SNS requirements.
The XML representation of the vocabulary conforms to XML Topic Maps (XTM 1.0) still today. Since 2004 SNS participates the international Ecoterm group of the Ecoinformatics
initiative which been considering SKOS
and OWL. 2006 SNS developed an OWL representation of its vocabulary which has not been implemented yet. Further information in:
