A flexible geospatial sensor observation service for diverse sensor data based on Web service

Achieving a flexible and efficient geospatial Sensor Observation Service (SOS) is difficult, given the diversity of sensor networks, the heterogeneity of sensor data storage, and the differing requirements of users. This paper describes development of a service-oriented multi-purpose SOS framework. The goal is to create a single method of access to the data by integrating the sensor observation service with other Open Geospatial Consortium (OGC) services — Catalogue Service for the Web (CSW), Transactional Web Feature Service (WFS-T) and Transactional Web Coverage Service (WCS-T). The framework includes an extensible sensor data adapter, an OGC-compliant geospatial SOS, a geospatial catalogue service, a WFS-T, and a WCS-T for the SOS, and a geospatial sensor client. The extensible sensor data adapter finds, stores, and manages sensor data from live sensors, sensor models, and simulation systems. Abstract factory design patterns are used during design and implementation. A sensor observation service compatible with the SWE is designed, following the OGC “core” and “transaction” specifications. It is implemented using Java servlet technology. It can be easily deployed in any Java servlet container and automatically exposed for discovery using Web Service Description Language (WSDL). Interaction sequences between a Sensor Web data consumer and an SOS, between a producer and an SOS, and between an SOS and a CSW are described in detail. The framework has been successfully demonstrated in application scenarios for EO-1 observations, weather observations, and water height gauge observations.