The Design And Establishment Of A Metadata Service System

With the development of the computer and GIS technology, especially the network communicative technology, spatial data sharing has become more and more popular. The data producer needs an efficient way to manage and maintain spatial data. Users need much faster, comprehensive and effective methods to find, access, get and use the good timely and precision geospatial data. Under this condition, metadata used to describe geospatial data's content and quality and condition and other information has become more important.The research and application of metadata have arrested more and more geographic academe's and industry's attention and have made a rapid development especially in the developed countries. Having investigated and analyzed some demonstrate meta databases and their management information systems, we find that most of the current systems are much similar with MIS in the common sense. However metadata has intimate connection to spatial data collection, integrate closely metadata and spatial data management is one of GIS's development trends from the point of view of original goal and function of metadata.According to the exist content standards for digital geospatial metadata, this paper made out a way of integrating metadata and geospatial data in a management system by having designed a reasonable metadata and spatial data construction and access mode. It includes the following aspects.1.The geospatial metadata service system discussed in this paper has a reasonable database design and adopted a hierarchical metadata structure and at the same time chosen a good way to describe and store and index the metadata. So it can give full play to the metadata's function.2.This paper has detailed the function of geospatial metadata searches. It has provided 4 ways of searching metadata, such as the direct condition search, the location dictionary search, the map window search and the hierarchical search. You can search by one of several items, like the caption, the author, the keywords and the time. You also can get the metadata by exact search or blurred search.3. We can describe the geospatial metadata by XML, which can facilitate the extension of metadata and the maintenance and system upgrading in progress. Having adopted the cluster technology, this metadata service system has the capabilities of high efficiency and stabilization.