Design And Implementation Of Agricultural Land Classification, Gradation And Valuation Metadata Information System

With the development of the computer and GIS technology, especially the network communication technology, the needs of data sharing have become more and more urgently. Metadata can be used to describe the content, quality, representation, spatial reference, management and .other characteristics of datasets. As an effective method to understand, discover, locate, valuate and maintain data, metadata has been generally accepted and widely used, and metadata standards and operation tools become important components of information construction.As a major part of presenting land resource survey, classification, gradation and valuation on agricultural land can promote the land management from "quantitative management" to "quantitative and qualitative management". The fundamental data and results are important as a reference to land resource management, such as land coordination, land expropriation and so on. But the fundamental data and results of agriculture land classification, gradation and valuation are difficult to share, because of various data type and distributed storage. Also it is difficult to produce, maintain and use the data without unified management on datasets. Metadata is effective for users to access, apply, search and share the data. So this dissertation studied the application of metadata technology in agricultural land classification, graduation and valuation data managing and sharing effectively, and achieved some significant results. They are as follows:(1) The establishment of agricultural land classification, gradation and valuation metadata system. The agriculture land classification, gradation and valuation metadata system is designed mostly according China's sustainable develoopment information sharing metadata standard and the characteristics of agricultural land classification, gradation and valuation data. The metadata system can describe the agricultural land classification, gradation and valuation data from all sides in general, and provide condition for managing and sharing agricultural land classification, graduation and valuation data effectively.(2) The implementation of agricultural land classification, gradation and valuation metadata system. The metadata system is described by XML Schema, so it is easy to be expressed, translated, displayed, queried and used.(3) The design of agricultural land classification, gradation and valuation metadata information system. The metadata information system is designed according to agricultural land classification, gradation and valuation metadata system and the characteristics of agricultural land classification, gradation and valuation work. The design includes total system design, system database design, and system function design.(4) The implementation of agricultural land classification, gradation and valuation metadata information system. According to the design of agricultural land classification, radation and valuation metadata information system, the metadata information system is implemented by multilevel distributed technology and component technology, so its software structure is very clear, and it can be easily updated, maintained and reused. The system can assist managers in managing, storing, discovering data effectively, and it can provide users with services of inquiring and accessing metadata.