Research On GIS Integration Based On Metadata And Web Service

Supported by the special subject "Model Integration and Trial Operation System Construction" in project "Xinjiang middle Tianshan High Resolution Snow Ice Monitor Evaluation", this Research studies the integration and publication of multi-source heterogeneous geographical data.A large number of geographic information systems and databases have been constructed to meet the developing requirements of scientific research, production management, social life and so on. In general, the target of different GIS is not the same, and then the platforms used to collect and produce geographical data for GIS are different, Therefore it results in different storage format, different mathematical basis and different data type of data. The geographical data with characteristics of multi-semantics, multi-space-times, multi-scales makes system integration difficult. On the other hand, large-scale geographic information system regularly consists of multiple subsystems. Reasonable mutual coordination and communication for data management and data sharing are required between different subsystems. How to implement the integration of multi-source heterogeneous geographical data is one of the key points for constructing integrated GIS.A brief introduction is given for describing the progress in the field about metadata and Web Services. A metadata content standard for describing geographical data in the research area is proposed based on analysis on its features and on the existing metadata content standard home and abroad. Storage policy for metadata and organization of geospatial data is studied, and an integrated management model for geospatial data is established based on metadata. On the basis, some key technologies for geospatial data publication services are discussed, and then a geospatial data integrated management platform is developed. The main research content and conclusion of this paper includes:(1) The paper makes a research on metadata description for geographic data and metadata storage model. Based on the research of currently existing metadata standard and the analysis of metadata content of geographic data source, with consideration on the special requirements for integrated data management, the metadata description for geographic data is studied. The content of metadata is classified into two categories: dataset metadata and management metadata. Dataset metadata is used to describe features of geospatial dataset. It is intended to help data consumer learn more about the data they need; management metadata controls the system functions and explains user’s operation. It helps to integrate datasets. The paper makes a research on dataset metadata and management metadata, and designs the physical storage structure of metadata.(2)Organization and storage of geographic data. The paper analyzes and arranges the geographic data, and discusses the classification and organization of geospatial data. Geographic data which can be stored in relational database is called structured geospatial data, and other ones which cannot be stored in database are called non-structured geospatial data. They are integrated together on basis of metadata.(3)Geographic data service publishing is studied in the article as well. Considering data organization on server-side and client design, dynamic publishing for thematic maps by web service is studied in the paper.(4)A GIS integrated platform based on metadata is studied and designed. The system architecture and major functions of the integrated platform are discussed, and implementation of the integrated platform is introduced.