GEOSPATIAL SENSOR WEB DATA DISCOVERY AND RETRIEVAL SERVICE BASED ON MIDDLEWARE

Recent advances in Sensor Web geospatial data capture, such as high-resolution satellite imagery and Webready data processing and model technologies, have led to the generation of large amounts of datasets from real-time or near real-time observation and measurement. How to find and retrieve the sensor or data complying with criteria such as specific time, location, and scale has become a bottleneck in Sensor Web-based applications. We proposed to answer the above question by building a catalogue service through a harvest service based on search engine and multi protocol data retrieval service middleware based on schema mapping and matching, called Data Discovery and Retrieve Service (DDRS). DDRS hides the complexity of the geospatial world behind its standard interfaces. DDRS consists of a harvest server, a discover server, a retrieve server and a portal server. The retrieve server explores three standard interfaces-Web Feature Service (WFS), Web Coverage Service (WCS) and Catalogue Service for Web (CSW) to portal server. The DDRS is designed to be capable to discover geospatial service and data object, and retrieve data from diverse homogeneous and heterogeneous service sources: WCS server from different sources, different versions and real time observation and measurement; CSW server from different sources and versions; WFS server from different sources, different versions and real time observation and measurement. The DDRS is designed and implemented by the service middleware and Java 2 enterprise edition (J2EE) technology. * An associate professor in wuhan university. His current research is focused on Geospatial Sensor Web, Polar information service, Web and Wireless GIS (W2GIS) and Geo Grid Computation. Email:cnc_dhy@hotmail.com