A SensorML-based Metadata Model and Registry for Ocean Observatories: a Contribution from European Projects NeXOS and FixO3

Discovering sensors and observation data is important when enabling the exchange of oceanographic data between observatories and scientists that need the data sets for their work. To better support this discovery process, one task of the European project FixO3 (Fixed-point Open Ocean Observatories) is dealing with the question which elements are needed for developing a better registry for sensors. This has resulted in four items which are addressed by the FixO3 project in cooperation with further European projects such as NeXOS (http://www.nexosproject.eu/).

1.) Metadata description format: To store and retrieve information about sensors and platforms it is necessary to have a common approach how to provide and encode the metadata. For this purpose, the OGC Sensor Model Language (SensorML) 2.0 standard was selected. Especially the opportunity to distinguish between sensor types and instances offers new chances for a more efficient provision and maintenance of sensor metadata.

2.) Conversion of existing metadata into a SensorML 2.0 representation: In order to ensure a sustainable re-use of already provided metadata content (e.g. from ESONET-FixO3 yellow pages), it is important to provide a mechanism which is capable of transforming these already available metadata sets into the new SensorML 2.0 structure.

3.) Metadata editor: To create descriptions of sensors and platforms, it is not possible to expect users to manually edit XML-based description files. Thus, a visual interface is necessary to help during the metadata creation. We will outline a prototype of this editor, building upon the development of the ESONET sensor registry interface.

4.) Sensor Metadata Store: A server is needed that for storing and querying the created sensor descriptions. For this purpose different options exist which will be discussed.

In summary, we will present a set of different elements enabling sensor discovery ranging from metadata formats, metadata conversion and editing to metadata storage. Furthermore, the current development status will be demonstrated.