LD4Sensors is an application that generates annotations for provided sensor-related details, while using the SPITFIRE ontology. It is currently in a Beta release and it is accessible by either an HTML form or a REST API. In this project the following aspects have been realized.

1. The SPITFIRE ontology has been defined with the aim of enabling descriptions for cross-domain sensor-related data and context (higher-level events). RDF4Sensors generates annotations based on the SPITFIRE ontology and searching the LOD for already existing definitions of specific details such as: (1) unit of measurement related to either sensor's observations or specific capabilities; (2) property observed by the sensor, e.g. Temperature; (3) property which specific capabilities refer to, e.g. Battery Life Time; (4) property referred by specific capability-enabling conditions, e.g. Battery Life Time equals to 2 hours only if (condition) the Humidity is under a certain range; (5) the type of Feature of Interest, e.g. a Washing Machine; (6) the location (7) sensor data’s owner and publisher. A search for FOAF profiles about them is performed.
2. The annotation is divided according to its dependency from changes in the device brand production or in the device owner (additionally a basic description that could be stored on the node itself is specified).
3. We grant access by both average users (without any prior knowledge about linked data), thanks to our online form, and by third parties' clients, thanks to our REST API.

The availability of tool that ease the annotation process without losing in quality and external data integration, is crucial to actually carry out the necessary and massive annotation of devices and data in a cost-efficient way.
The RDF4Sensors sensor annotation provider, is meant to be included into the inContext-Sensing application.