The Research And Implementation Of WebGIS Map Display System Based On SVG

In the traditional GIS, data is very large, there are a variety of data formats, and complex structures. But network applications requires lightweight information technology, therefore, the display system of map based on the SVG format has become a research direction of current WebGIS.This paper first introduces the development of current WebGIS and the characteristics of development platform, and presents the SVG technology and its application on the Internet. It describes the division of system modules and related functions. It analyses links between modules. The system is divided into two parts, foreground and background, the foreground displays the map on the Internet, the background mainly manages map. Secondly, this article makes secondary development of MapObjects in VB 6.0, through SVGMapper, the extension function of ArcView, the map files are converted from the shape format to the SVG format. It implements the access and management of map data, and the map in SVG format is displayed in the dynamic web page. Finally, it describes the application of Ajax in WebGIS. The ASP.NET development framework, embedded with Ajax, is used. Through Javascript calling SVG DOM interfaces, the display of map in SVG format is controlled, it embodies the operation functions of map in client of WebGIS. Based on the technology of Web Service, a display system of map in WebGIS is gradually set up. Compared to the grid map, this article uses the map in SVG format based on XML, whose data size is smaller in the transmission of network. The map data of different regions, accumulated over a long period, is selectively displayed in the network to many users, the system application of WebGIS is implemented. With part of the resource of map about Ningbo in Zhejiang Province, it implements an approach to convert map from the shape format to the SVG format. The map in SVG format is used in WebGIS. It implements the base operations on the map in the web page, and provides a simple query function of bus transfer schemes. The feasibility and effectiveness of the system are validated by experiment.