导　　师： 杨崇俊

学科专业： 070503

授予学位： 硕士

作　　者： ;

机构地区： 中国科学院研究生院

摘　　要： 网络地理信息系统/(WebGIS/)作为网络技术和GIS技术的结合点，从其诞生以来，它的发展就与计算机技术的进展息息相关。从90年代开始，随着以Internet为代表的网络技术的迅猛进步，WebGIS的应用得到了飞速的发展，也出现了一系列的问题。这些问题中，有些是网络软件本身固有的问题，如跨平台跨语言的问题，软件复用的问题等。有些是GIS软件本身固有的问题，如数据互操作问题等。所以，要有效地解决WebGIS的这些问题，就必须从GIS技术和网络技术这两方面来进行研究。 目前有两大类型的标准化组织在研究和解决这些问题：专注于网络技术方面的W3C、UDDI等组织和专注于地理信息共享和互操作方面的ISO TC211、OGC等组织。这两类组织都提出了一个Web Service的概念，但是这两个概念并不完全相同。W3C提出的Web Service概念注重于技术上的解决方案和实现。而OGC提出的Web Service概念则更专注于它所表达的服务这个概念，它非常强调地理信息服务在网络服务中的地位和作用。也就是说，OGC注重于Web Service的框架和概念层面，而W3C注重于Web Service的实现和技术层面。本文对这两方面的研究工作都作了介绍，并且阐述了这些组织的研究成果对WebGIS的作用和意义。 在对W3C和OGC相关标准研究的基础上，本文以Web Service为系统结构的技术核心，提出了WebGIS的概念模型。在这个模型的基础上，从概要设计开始，逐步细化，最后提出了WebGIS原型系统。该原型系统包括数据服务器，应用服务器和客户端三个独立的部分。这三个部分之间通过交换消息来协同工作，以共同完成用户需要的功能。 根据该原型系统，本文给出了基于Visual Studio.Net平台的原型系统的具体设计和实现过程，包括数据服务器、应用服务器和客户端的设计和实现。数据服务器的开发采用自底向上的开发模式，包括动态链接库的开发、基于动态链接库的COM组件的开发以及基于COM组件的Web Service功能的开发等几个步骤。由于采用了瘦客户端的应用模式，所以客户端的实现主要是界面设计以及与应用服务器交互两部分内容。应用服务器端主要是利用数据服务器提供的Web Service，向客户端提供各种服务功能。从而用Web Service的方法实现了一个三层结构的可扩展的WebGIS系统。 最后，本文对基于Web Service的WebGIS系统的研究和实现做了总结，并提出了在WebGIS的应用中需要进一步研究和解决的问题以及前景展望。 As a conjunction of Internet technology and GIS technology, the development of WebGIS has closely related with the development of Computer technology. From 90s, as the network technology developed quickly, which presented by Internet, WebGIS applications have developed rapidly. Meanwhile, there also appeared many questions in WebGIS systems. Some of these questions are brought by Web software, such as the cross-platform and cross-language problems. Others are brought by GIS software, such as the data interoperative. So, we must do research in both GIS and Web areas to efficiently solve these problems. At present, there are two types of standardization organizations who try to solve those problems: the organizations who pay attention to Web, such as W3C, UDDI etc, and the organizations who pay attention to geographic information share and interoperability such as ISO TC211, OGC etc. All these two organizations present the concept of Web Service, but they are different. W3C pay more attention to the technology solutions and implementations, while OGC pay more attention to the concept of services, that is, OGC emphasis the status and function of geographic information services in Web Services. In another word, OGC emphasis the framework and concepts of Web Service, W3C emphasis the implementation and technology of Web Service. In this paper I first introduce the Web Service from W3C and OGC seperately, then expatiate the effect and significance of their protocols and standards to WebGIS. Base on the research about W3C and OGC standards, I present a conceptual model of WebGIS. In this model, I utilize Web Service stack as the core technology reference to the model architeture. Then based on this conceptual model, I present the sketch design and the WebGIS prototype. This WebGIS prototype includes three indepedant parts: Data Server, Application Server and Client. These three parts exchange messages to work together and accomplish user's command. Then, based on Visual Studio .Net development platform, I present the detail design and implementation procedure of this WebGIS prototype, which include the design and implementation of Data Server, Application Server and Client. The development of Data Server uses the from-bottom-to-top development mode. This development procedure include several steps: the development of the dynamic link library, the development of COM component based on Dynamic Link Library and the development of Web Services based on COM component. Because I use thin client application mode, so the implimentation of the client just includes two aspects: the interface design and the interaction with Application Server. In the implementation of the Application Server, I mainly use the Web Service provided by Data Server to provide the various functions to client. By these steps, I implement a 3 tier scalable WebGIS system by Web Service. Finally, I conclude the research and implementation of WebGIS system based on Web Service, and then present the problems that need to be solved father and the vista of Web Service.

关 键 词： 服务 网络服务 网络地理信息系统 地理信息网络服务 网络服务 服务框架 组件对象模型

分 类 号： [P208]

领　　域： [天文地球] [天文地球]