Study On The Application Of Data Grid In The Spatial Data Sharing

The grid technology is the third generation network agreement which at present recognizes, the grid is for solve one kind which macrozonality network resources comprehensive sharing proposed to be brand-new based on the Internet application technology, after it already became continues traditional Internet, the Web third information technology tide, after continued Internet, the Web application information technology revolution lead, the country information service strategic in frastructure. The grid is the establishment in Internet and above the Web foundation, is one kind new based on the network service frame, is to present Internet, the Web technology important development.Internet has realized between computer hardware interlocking.The Internet technology appearance, the independent computer in dividual company will become the whole, will pay attention to between the machine with emphasis the correspondence and the exchange of information, but will not have the means to share other machines the resources, also not nicely for will complete the computation the geographic distribution resources union use.Web has realized grid resources connecting. Web starting, connects through the browser the homepage, the computer may do including the electronic commerce more matters, but, various professions interlock in the application stratification plane exchange have not realized by far, the computer use also far was inferior to the telephone is that convenient. Web lacks the characteristic which the rich interactive model needs.But the grid attempts to realize on Internet all resources comprehensively to link up, including computation resources, memory resources, correspondence resources, software resources, information resource and knowledge resources comprehensive sharing.Enterprise computing (for example: CORBA, J2EE) the main interactive form is the customer/server (C1ient/Server, C/S) the structure. Does it pay attention in an enterprise or the organization carries on resources sharing, which - server the user indicates through the client must send out the service request to, but is not the cooperation uses the cross organization the many kinds of resources. The grid cooperated the cross management territory resources, the computation pattern has also had very sweeping change. The Internet development many different types server all will connect in the network, the computer application system development tendency will start the beginning from the C/S structural transformation for the client/network (Client/Network) the structure, will advance together - step transforms into the client/hypothesized Environment (Client/Virtual Environment) the structure.In the grid, each kind of server forms under the high level system software control to have the huge computation and the data-handling capacity service environment, provides integrated to all the varioustrades and occupations and the social populace the information service. The grid and the CORBA union has the vital significance, the grid therefore may visit the enterprise to calculate the environment. The use grid agreement, may calculate in the environment in the different management territory enterprise to realize the application cooperation, strengthens between the CORBA customer and the non- CORBA customer interactive.The grid computation emphasizes the large-scale multi- organizations macro zonality ability and so on under environment high performance computation, long-distance access, transparent data manipulation, and consideration use special agreement. This is because: First, the grid can realize in the application stratification plane true to interlock exchanges, namely in the user use stratification plane interlocks exchanges.Next, the grid may realize comprehensive resources sharing, the grid the high performance computer, the super computing system, the large capacity database and all that each kind of information and the state-of-art equipment which disperse the geography in connects through the network, the realization computation resources and information resource sharing, provides integrated in comparatively wide range the high performance computation environment and the information service. Third, the grid needs to use the international standard. The grid further development will like the Internet technology, the Web technology is same, will have the huge influence to the human society.In brief, the existing technology already cannot satisfy each kind of type resources sharing, also has not provided the basic resources sharing frame, satisfies the sharing relations which the macrozonality resources is nimble, may control. But, these technologies may coexist, mutually promote, further impels the grid technology the fast development, realizes each kind of resources"namely to think namely uses".But the geographic information system (GIS) from started already accumulated the massive data to the present, and widely applied to each domain, in domain and so on national economy construction hasplayed the vital role. The geographic information system processes the spatial information, usually is through procedure and so on data acquisition and input enters the geographic information system, needs person's operation, therefore waste manpower and time. Along with network geographic information system (WebGIS) development, the people hoped can share these data, reduces nonessential repetition gathering, shares data acquisition together the expenses, fully usesthe resources, enhances the economic efficiency. This kind of sharing information idea has its rationality. Many information may repeatedly use, for example vegetation information, also may use in the natural resource management, also may use in the ecology management Next, the network technology rapid development has also created the condition for information sharing. The network provides the quick information exchange method and the strong message resources impetus all the various trades' and occupations' development, brings thee norm ous convenience for people's production life. In the last few years, global scope Internet (Internet) by the astonishing speed growth, information sharing not only becomes in particular possibly, moreover is more and more popular. The various countries all is carrying on this aspect the research. At present, our country is carrying on the national space data infrastructure the construction, its goal realizes geography space data sharing.Thereupon revolves the data sharing question, proposes the data grid based on the grid computation theory. This article mainly aims at the data grid to conduct the research in spatial data sharing application aspect, The main research content as follows (1) has earnestly studied the existing grid system structure and the existing network sharing system model, compared with pointed out between each kind of system structure is different and the good and bad points. (2) analyzed has studied in existing grid GIS the data sharing insufficiency, as well as the data grid and the data sharing relations, proposed solved this difficult problem with the data grid integration. (3) the comprehensive analysis existing space data sharing pattern in realizes in the PT level geography information data sharing insufficiency, has analyzed the grid technology in the data sharing related technology, obtains it inevitably to become the next generation network agreement, also will be the multiple source data seamless integration essential support technology. (4) unifies the data grid and the multiple source data seamless integration theory proposes the confluence - divergence spatial data sharing pattern.This quite practical and is easy the geography information through the electronic map which realizes to integrate the platform, carries on experiments the confluence - divergence space data sharing pattern to be practical and the feasibility, has the difficult problem by time solution quite large-scale cyberspace cyber space data sharing in.