Realization Technologies Of WebGIS Based On SVG

In order to solve the sharing and interoperation between spatial data, The OGC has put forward a spatial data exchange format GML based on XML. As a kind of language based on XML, GML is used for transmission and storage of geographical and geography referential information. At present Web browser cannot show in figure the spatial data that described in the GML files. SVG is a standard put forward by W3C in display and transmission of Vector figures. It takes advantages of vector graphics, bitmaps and pure texts and can well meet GIS demands for spatial data graphical display. And now both Adobe SVG Viewer and IBM SVG View can achieve the display of SVG files?Through introducing SVG specification and analyzing the possibility of using in WebGIS, the paper tries to set up SVG based on WebGIS system structure and explain its workflow and design scenario.The key point of the paper is to analyze the realization technologies of WebGIS based on SVG, including spatial information visualization, spatial analysis, multi-scale and data expression. Then it summarizes and analyzes realization degree of SVG to these functions and draws a conclusion. SVG is suitable for describing the two-dimensional vector figure, including symbol, thematic picture, legend, etc., and can also well represent multi-media geographical information. However its application in three-dimensional artificial pictures and virtual reality is nearly blank. SVG can develop and realize some simple special analysis through procedure. The expression of multi-scale geographical is achieved by connected with Database, the procedure can translate the data into SVG files and through it to the Client, but the speed still remains to strengthen.The paper provides a WebGIS integrated system demonstration based on SVG and explains the key technologies studied in this paper.