An extensible semantic catalogue for geospatial web services

Searching for web services is a challenging task due to the diversity of existing discovery tools. Varying standards for service descriptions require different tools to query their content. These standards exist for good reasons. Web services are used in different application environments and special solutions are required for their integration. We suggest an architecture for web service catalogues, which takes this diversity of standards into account. Its extensibility allows for a complete separation between service discovery and service description. Using ontologies for the storage of service descriptions enables the support of different description standards without loosing their specific advantages. The discussion and implementation focuses on geospatial web services. Due to the heterogeneity of spatially referenced data, different specifications exist for them, making the problem of different standards for service discovery and service description most evident here

Publication and Discovery of Semantically Annotated Geospatial Web Services

Proceedings of the 26th International Conference on Informatics - Informatics for Environmental Protection, Sustainable Development and Risk Management, August 29 - 31, 2012 Umweltbundesamt DessauEnvironmental information and services have become a crucial asset in the creation of decission support systems. Unfortunately, this information and services are not usually exposed in an interoperable and standard way, limiting their reusability and impact in the community. Publishing and discovering geospatial information and services on the Web is therefore an important challenge in order to create a breeding ground for collaboration and more sophisticated environmental platforms. Based on common standards defined by the Open Geospatial Consortium (OGC) as the starting point to ensure interoperability, we propose a discovery mechanism based on semantic annotations. OGC service descriptions are annotated with SAWSDL and linked to concepts in domain ontologies, following a common semantic service model. We seamlessly integrate the semantics in the standard OGC discovery infrastructure, extending the CSW service catalogues with semantic publication and discovery. Semantics queries can be created based on formal languages like WSML, significantly improving the precission of discovery. In this paper we present our approach, which provides a semantic infrastructure for publication and discovery of environmentally enabled web services

Geospatial Standards for Web-enabled Environmental Models

Serving geographic information via standardized Web services has been widely accepted as a useful approach. Web-enabled environmental models simulating real-world phenomena are, however, rare. The models predict observations traditionally served by geospatial Web services compliant to well-defined standards. Using standardized Web services could support decoupling of models, comparison of similar models, and the automatic integration into existing geospatial workflows. Modeling experts face several open issues when migrating existing environmental computer models to the Web. The selection of the Web service interface depends on the input parameters required for the successful execution of the computer model. Losing control over the execution of the models, and consequently also the confidence in model results, can be addressed to a certain extent by using translucent and standardized workflow languages. Mechanisms and open problems for the implementation of geospatial Web service compositions are discussed. Two scenarios about oil spills and the exposure to air pollution illustrate the impact of unconfigured model parameters for standard-compliant spatial data clients

Semantically-Enabled Sensor Plug & Play for the Sensor Web

Environmental sensors have continuously improved by becoming smaller, cheaper, and more intelligent over the past years. As consequence of these technological advancements, sensors are increasingly deployed to monitor our environment. The large variety of available sensor types with often incompatible protocols complicates the integration of sensors into observing systems. The standardized Web service interfaces and data encodings defined within OGC’s Sensor Web Enablement (SWE) framework make sensors available over the Web and hide the heterogeneous sensor protocols from applications. So far, the SWE framework does not describe how to integrate sensors on-the-fly with minimal human intervention. The driver software which enables access to sensors has to be implemented and the measured sensor data has to be manually mapped to the SWE models. In this article we introduce a Sensor Plug & Play infrastructure for the Sensor Web by combining (1) semantic matchmaking functionality, (2) a publish/subscribe mechanism underlying the SensorWeb, as well as (3) a model for the declarative description of sensor interfaces which serves as a generic driver mechanism. We implement and evaluate our approach by applying it to an oil spill scenario. The matchmaking is realized using existing ontologies and reasoning engines and provides a strong case for the semantic integration capabilities provided by Semantic Web research

The ENVISION Environmental Portal and Services Infrastructure

Part 3: Environmental Information Systems and Services – Infrastructures and PlatformsInternational audienceThe ENVISION Portal is a Web-enabled infrastructure for the discovery, annotation, and composition of environmental services. It is a tool to create Web sites dedicated to particular domain-specific scenarios such as oil spill drift modeling or landslide risk assessment. The underlying architecture based on pluggable user interface components is briefly discussed, followed by a presentation of the components resulting from the first iteration of the implementation. A walkthrough explains how to create a scenario website and populate it with the user interface components required for one specific scenario. The paper concludes with a discussion of open challenges identified during the implementation

Undefined 0 (0) 1 Injecting semantic annotations into (geospatial) Web service descriptions

Abstract. Coupling existing geospatial applications with Semantic Web technologies depends on solutions to also semantically enable underlying information sources. Spatial data complies with well-established standards to support seamless integration into applications ranging from commercial Geographic Information Systems (GIS) to open source web mapping clients. To ensure compatibility with existing solutions, the semantic enablement of spatial data sources has to reflect both worlds. Semantic annotations close this gap by linking between legacy non-semantic Web service metadata and their semantic counterparts. The open source Semantic Annotations Proxy (SAPR) is a light-weight RESTful API deployed as free service which "injects" semantic annotations into existing Web service descriptions without breaking the standards. The presented approach decouples the annotations from the original metadata. This ensures the separation of concerns between data providers and end users with different and sometimes conflicting views on annotations. The presented approach is focusing on W3C-and OGC-compliant Web services, but can be theoretically applied on any kind of information source with structured metadata

Undefined 0 (0) 1 Injecting semantic annotations into (geospatial) Web service descriptions

Abstract. Coupling existing geospatial applications with Semantic Web technologies requires solutions to also semantically enable underlying information sources. Ontologies help to formally specify the semantics of underlying data models and Web service capabilities. Spatial data complies with well-established standards to support seamless integration into applications ranging from commercial Geographic Information Systems (GIS) to open source web mapping clients. To ensure compatibility with existing solutions, the semantic enablement of spatial data sources has to reflect both worlds. Semantic annotations close this gap by linking in between the existing non-semantic Web service metadata and their semantic counterparts. The open source Semantic Annotations Proxy (SAPR) is light-weight RESTful API deployed as free service which "injects" semantic annotations into existing Web service descriptions without breaking the standards. The presented approach decouples the annotations from the original metadata. This ensures the separation of concerns between data providers and end users with different and sometimes conflicting views on annotations. The presented approach is focusing on W3C-and OGC-compliant Web services, but can be theoretically applied on any kind of information source with structured metadata