Shared Metadata-based Groundwater Data Technology Research

Groundwater data sharing is an effective solution to the problem of repeating monitoring groundwater and collecting data resource, so as to break the barrier between different departments. Since the increasingly thinking much of science data sharing and the urgent need of groundwater data sharing, it is significant in theory and in practice to systemically research the theory, method, key technology and solution of groundwater data sharing.Based on the review of groundwater informatization at home and abroad, three key problems on groundwater data sharing are raised, namely , An architecture of groundwater data sharing , the customization and extension of groundwater metadata and the sharing of groundwater spatial data.An architecture of groundwater data sharing is put forward to share distributed heterogeneous groundwater data resource, which is logically uniform and physically distributed. The architecture is realized by concentrated management and dispersediy storing data-entity in general center-subcenter mode. The system functions are designed according to two main routes, which are service function and management function. The process of service function includes gathering, querying, viewing and downloading data, and the process of management function includes storing, classifying, auditing data, safety control and analysis log.A three-tier architecture of groundwater core metadata , namely "module-complex element-data element", is brought forward, which consisted of seven modules, twelve complex elements and forty-five data elements totally. The groundwater core metadata architecture designed in RDF/XML framework includes a scheme of groundwater metadata extension application which is achieved by directly inheriting and modifying the existing groundwatermetadata modules/data elements based on groundwater core metadata, or by building new metadata modules/metadata elements according to groundwater core metadata semantic rules.Based on the analysis of current spatial data sharing technology, groundwater data sharing is realized by combining spatial information data with WEBGIS. Spatial information metadata provided spatial data operation with linking parameters, including three parts: spatial service stations, spatial service information and spatial data download service, which totals up to ten metadata. The corresponding spatial data are shown and operated in WEBGIS according to spatial data metadata.The scheme is carried out in China Groundwater Information Share Platform project using JSP, JavaBean and JDBC technology etc. in J2EE environment. ArclMS is selected as WEBGIS and Oraclegi is the database management system in the project. At last, the key technology of metadata operation based on XML and parts of the methods to realize the service function in Groundwater application are discussed.