基于Java的Web GIS关键技术研究

【作者】 宦兆骅；

【导师】 童玲；

【作者基本信息】 电子科技大学 ， 测试计量技术及仪器， 2006， 硕士

【摘要】 传统的基于客户端/服务器结构的地理信息系统(GIS)无法适应Internet环境下的开放性、安全性和多样性,这也使其面临着丰富的、具有无限潜力的发展空间。新一代GIS在组成结构和应用技术等方面与传统GIS有了很大的不同。随着第三代Web技术的出现,Web GIS应运而生。基于Internet / Intranet的Web GIS是GIS发展的趋势,以现代网络为基础,建立基于浏览器(Browser)/服务器(Server)的Web GIS,充分利用Web资源,向广大GIS用户提供更为广泛的地理信息服务,已经成为目前国际GIS发展的主要趋势。Java集安全、健壮、跨平台、高性能于一身,是面向Internet编程的理想选择。本文在探讨现有的几种Web GIS实现模式的基础上,提出一种基于Java技术的Web GIS构造模式,在客户端和服务器端构建一个完整的GIS系统,研究其中的若干关键技术,包括数据处理、服务器和客户端设计等。整个系统共分为三层,包括客户层、Web层和数据层。客户层显示客户最终看到的系统界面,主要由在浏览器里运行的Java Applet负责,并作为客户与系统交互的接口部分。Web层由Java Servlet作为底层平台,接收到客户层发来的指令,从数据层取得所需数据并加以处理,将结果返回给客户层。数据层存储着系统的所有数据,根据Web层的请求查询满足条件的数据返回给Web层。另外,数据的预处理工作也是非常重要的。为了满足网络环境下并发访问和数据传输方面的要求,我们根据数据的不同种类分别加以处理,使其符合系统的设计需要,为系统的最后实现奠定了基础。通过设计这样一个示例系统,可以看出Java技术在实现Web GIS中的优越性。经过测试,系统较好地满足了设计要求,对互联网地理信息系统的实现做了有益的探索。更多还原

【Abstract】 The traditional Geographic Information System (GIS) based on the structure of Client / Server could not afford openness, security and diversity in the environment of Internet. Meanwhile, it means a huge potential for advance. The new generation of GIS is different from the traditional one at aspects of composing structure and applied technology. Web GIS appears along with the progress of Web technology. It has been a critical trend for the development of international GIS that Browser / Server based Web GIS takes full advantage of Web resources to provide wider range of geographic services for people through modern net infrastructure. Java is a general solution which features cross platform, robustness, security and high performance. It is ideal for Internet oriented programming.This thesis brings forward a Web GIS construction pattern after investigation and analysis of some application modes and realization approaches. A prototype system is built to research some key technologies of Java-based Web GIS. The whole system can be divided into 3 tiers, including client tier, Web tier and data tier. The client tier is a interface between user and system. The Web tier is based on Java servlet. It receives commands from client tier and gets data from data tier. After processing, it sends results back to the client tier. The data tier restores all data and sends data to Web tier according to query directives. The data preprocessing is also important. We deal with data in different ways based on different characteristics of data to adapt them to concurrent accessing and net transmission.The design of the prototype system embodies superiority of Java technology in building of Web GIS. The system satisfies design requirements proved by testing. It makes beneficial exploration for the realization of Internet GIS.更多还原