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Studies on the Key Technology of Spatial Data Sharing on the Internet Wang Lei, Chi Tianhe, Zhou Xu, Chen Huabin, He Jianbang Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101,ChinaM Email : wangl@igsnrr.ac.cn
1 Introduction
China’s Sustainable Development Information Sharing System is a spatial data management and analysis system that possesses the base functions of webGIS. Chinese sustainable development information can be accessed through this system. These data include information of vegetation and animals resources, microbe species, crop species, forest, land use, nature protected area, geology and mineral resources, ocean resources and environment, climate and integrated information of disasters. All these data can be queried and accessed through many approach, some basic analysis and professional analysis function are also supplied. 2 System concept design China’s Sustainable Development Information Sharing System makes fully use of the quick development technology of Internet, combing many new technologies such as webGIS, Web database, metadata, network dynamic model Fig 1 is the frame structure of China’s Sustainable Development Information Sharing System.  Figure 1 The Frame Structure of China’s Sustainable Development Information Sharing System This model includes user tier, server tier, data tier, network tier, technology tier and management tier etc. They connect with each other,integrating as a whole. Users can access this system through user tier. From users perspective,this system is a information serving institute,website can be visited through Internet,information can be browsed by personal manner,free download or with some charge. Server tier can supply advanced service to users, including information query, data download, dynamic operation model etc. Server tier is set up on data tier,it also can support user tier. It is mainly represented as an integrated software system combing with nertwork, data and hardware. In order to better make use of the data on server tire, some advanced technologies were taken, such as WebGIS technology, metadata technology etc. Data tier is the core of this system. This value of this system was decided by the practicality, integration, precision and the dynamic update ability of this system. The data in this system is authority data including resource, environment and disaster;It is a distributed database in which data is distributed in network center and network sub-center. All database have a characteristic of spatially referenced earth, and can be display on the map. Network tier is a virtual network that is organized together through common management, common technology and common user face based on the Internet. It connects all parts of this system together, users can visit this system through Internet. Technology tier cross both above four tiers, it makes use of all kinds of technology, ensuring the realization of system goal. In one hand, this system make use of present matured technologies,such as Internet, database, Web technology etc ; On the other hand, a series of key technologies need to be solved,these technologies integrate with above four tiers,making system realization possible. In network tier, it is required to ensure the connection between network center and sub-center. It also is required to ensure the internet security;In data tier,it is required to finish former database’ alteration and build a distributed database system;In server tier,it is required to develop client and server software,integrating with all kinds of business software;In user tier,it is required to build a web main page,communicated effectively with users. Management tier has tight connection with former five tiers,it is the guarantee of system realization and operation normally. During system construction period,management tier need to harmonize with each other. After system construction,it need to ensure it is a self-sustain, normally operate system. |