【作者】 涂振发；

【导师】 喻光明；

【作者基本信息】 华中师范大学 ， 地图学与地理信息系统， 2008， 硕士

【摘要】 随着Internet的发展,越来越多的桌面应用转向Web平台。在GIS领域,Internet技术与GIS相结合产生了WebGIS。WebGIS改变了空间数据的获取、传输、共享和应用的方式,是GIS未来的发展方向。当前随着技术的发展,WebGIS的应用领域不断的扩展,新的实现技术也不断的出现。基于Ajax的Google Maps的推出为WebGIS带来了新的设计模式。Ajax可以很好满足WebGIS大量的即时交互、频繁的服务器通讯以及数据传输等要求,有效的减轻服务器的负担,减少数据的传输量,客户端不需要下载任何插件,克服了传统Web应用的白屏等待现象等问题。因此,类似Google Maps的在线地图服务大量的出现,Ajax成为WebGIS的主流实现方式。本文应用武汉市的MapInfo格式地图,使用ASP.NET AJAX作为Ajax框架,结合Web Service建立了一个基于Ajax的WebGIS平台。通过研究,本文初步得到了一个应用Ajax建立WebGIS的解决方案,提出了该模式下的WebGIS的实现原理、体系结构,并且对部分功能的实现给出了示例。研究中,使用ASP.NET AJAX开发客户端功能,由于ASP.NET AJAX对JavaScript做了大量的封装,系统针对不同的浏览器只需要开发一套代码,极大的改善了不同浏览器间的兼容性问题。同时ASP.NET AJAX植根于ASP.NET 2.0,便于利用ASP.NET 2.0的强大功能。服务器端使用ASP.NET 2.0开发Web Service为客户端提供数据,使得数据与用户界面分离。研究中,还尝试将MapXtreme 2005引入到WebGIS的地图服务器的开发,用以增强系统的GIS功能;将SVG、VML等引入到客户端的开发,用以实现客户端的路线绘制等功能。更多还原

【Abstract】 With the Development of the Internet, more and more tabletop applications switch to the Web platform. In the GIS domain, the combination of Internet technology and GIS has caused the emergence of WebGIS. WebGIS changed the way of geo-spatial data acquisition, transmission, sharing and application, and it will be the direction of future GIS development. With the technical development, the WebGIS are used in more and more fields, and more and more new techniques also appeared. Google Maps based Ajax provides a new WebGIS design pattern. Ajax could meet the WebGIS requirement, such as the large number of immediate interaction, the frequent communication to servers and the data transmission requirements. It could also effectively reduce the burden on the server and the amount of data transmission. The client does not need to download any plug-ins. Ajax overcomes many problems of the traditional Web application, such as the white screen waiting phenomenon. Therefore, when a large number of online map services, such as Google Maps, appeared, Ajax has become the main way of building WebGIS.The Maplnfo map of Wuhan was used to form An Ajax based WebGIS platform using Web Service and ASP.NET AJAX as the Ajax frame. Through this research, a solution of establishing a WebGIS using Ajax was obtained, the principle and architecture of this pattern was proposed, demonstration of some of the functions were given. In the research, ASP.NET AJAX was used to develop client function. Because it has made a massive seals to JavaScript, and only one set of codes is needed to different browsers, the compatibility problem between different browsers was greatly improved. Simultaneously, ASP.NET AJAX was based on ASP.NET 2.0, so the functions of ASP.NET 2.0 can be used expediently. ASP. NET 2.0 was used to create the Web Service to provide data for the client-side, in order that data and the user interface can be separated. Some other techniques were also used in this study. For example, MapXtreme 2005 was used in the map-server development to enhance the GIS functions. VML and SVG was used in the client development to realize the client’s line drawing functions更多还原