The Research On Metadata Organization And Management For Urban DLG Database

The role of basic geographical data in urban informatization construction has become increasingly conspicuous. DLG data as the most important basic geographic data are important strategic resource for city's informationization and are used widely. Urban DLG databases, which meet the demands from the development of the cities basically, have been built in most cities. The application of DLG data resource is affected by the problems of database management, maintenance and DLG data resource sharing. Spatial metadata, which describes the content, quality condition, representation, spatial reference, management and other data characteristics of the data contained a spatial dataset of geographical information, is one of the important conditions to making full use of spatial data resources by spatial data sharing. Using spatial metadata is an effective method to access, locate, evaluate, mine, understand and maintain spatial data. The objective of this thesis is to design and develop a metadata management system, which provides some functions such as building metadata database, querying metadata, updating metadata and publishing metadata for urban DLG database by researching on the content and organization mode of metadata of urban DLG database. The system can help the data production departments to maintain and manage the urban DLG database better.Firstly, in the paper, we review the status-quo on metadata research at home and abroad; present the concept, role and meaning of spatial metadata. The XML database technique is dissertated briefly. Facing to concrete application demand, the metadata schemas for different metadata of urban DLG database are formed by extending metadata related standards, laying the foundation for the future research work.Then, the organizational complexity of spatial metadata and the deficiency of existing organization mode for spatial metadata are analyzed in detail. The gradually organization of metadata for urban DLG database based on the XML database is proposed around the feature of metadata for urban DLG database. This paper gives a model of metadata management system for urban DLG database concerning several key technical issues that should be resolved. Meanwhile, an in-depth study on synchronous update mechanism of metadata database is made for urban DLG database.Finally, we implement a Prototype of such system. Also we have a conclusion on our work and propose the next to do.