Research And Application Of WebGIS Based On SVG

WebGIS technology is the combination of GIS technology and Internet technology,and it is expanding the applied field of GIS to any aspects of the mankind society,being the popular information tool.With the rapid development of modern Internet technology, WebGIS has also been developing at high speed.SVG based on XML,is the Web vector graphic solution of W3C recommendation.It is a completely open standard format of two-dimensional vector data, and has very strong scalability. Using SVG, we can show up a wide range of high-quality vector graphics at web pages. If geospatial data is encoded into SVG for spatial data storage, transmission and performance, the problems of data dissemination generated by the existing spatial data format will be effectively eliminated. In addition, the graphic elements in SVG have animation function, so animated maps can be produced, making the maps shown before the users more expressive. From the above we can see that applying SVG to WebGIS is of great significance.The key question of applying SVG to WebGIS is the realization of the function of GIS interaction,this paper will through the research of SVG,DOM and AJAX technology,realize the key functions of WebGIS,such as coordinate transform, map control, spatial information inquiries, buffer analyzes.This paper analyzes the characteristics and grammar of SVG, researches the implementation technology of applying SVG to WebGIS, makes the architecture of WebGIS based on SVG, and designs a WebGIS system of digital campus based on SVG. The system build a Web application server for interaction of client side with database and a graphical interface for client side which is based on SVG, is able to realize the integrated management of geospatial data and attribute data, combining SVG, Asp.NET, JavaScript and other technologies,good results have been achieved.It is proved that applying SVG to WebGIS has the characteristics of low price,better expansibility and convenient for use, comparing to the expensive commercial software of WebGIS,and satisfies requirement of releasing customizing map service.