Research On Distributed Web-ECDIS Based On XML Technology

Based on analyzing of the existence ECDIS (Electronic Chart Display and Information System), the paper indicates that ECDIS includes some limitation about its using scope. And the paper points out that we must research the ECDIS based on Internet thoroughly, if ECDIS wants to provide service widely.This paper analyses the deficiency of data model of the current ECDIS in network environment, and provides its resolvent. The paper integrates the characteristics of XML (Extensible Markup Language) such as multi-platform, expandability, legibility and ability of organizing all kinds of information, and references the geography space model of the criterion of GML2.0 that is established by OGC (Open GIS Consortium), and establishes the model of chart data with XML. This data model is suitable for storing and transmission of data in the network. Based on the criterion of SVG (Scalable Vector Graphics), which is established by W3C (World Wide Web Consortium), this paper describes the symbol of chart object using the technology of SVG, it makes the symbol of chart object have the high ability of expanding.This paper establishes the distributed WEB-ECDIS based on XML with the technology of distributing, XML and SVG The paper clarifies the design theory of system in particular, and analyses the characteristic of design, and summarizes the limitation of structure of traditional distributed system. This system adopts "3-tiers" framework, and remedies the limitation of traditional distributed system. The system consists of server, middle components and clients, these parts balance the load and advance the capability of whole system. The server of the system disposes the module of XML switcher with the mechanism of RMI (Remote Method Invocation), so the system can admit multi-data. The middle components deal with the request of users by the Servlet technology, and assume the complex operation logic, In clients, system integrates the technology of Applet and SVG, and advances the new structure thatinserts the SVG into applet, so clients can take on multi-platform and great efficiency.The distributed WEB-ECDIS based on XML remedies the limitation that exists in the traditional ECDIS, it is great structure of ECDIS based on internet. This system enlarges the using scope of ECDIS, accelerates the development of ECDIS. Also brings great advantage in field of navigation.