Study And Implementation For SVG Spatial Data Storage Technology

With the SVG (Scalable Vector graphic) in WebGIS applications gradually in-depth, thetechnology of SVG spatial data storage is becoming increasingly important research. Tra-ditional database systems for SVG base on XML format support in its logical structure anddata integrity in storage, and space index have a serious shortage, limiting the expression,exchange and sharing of SVG in WebGIS. In this context, this paper studies a spatial datastorage management system, defining a logical memory model memory storage and retrievaloperations for the SVG spatial data, having nothing to do with characteristics of the underly-ing physical storage, and basing on the characteristics of SVG spatial data establishs a newindexing mechanism. In a traditional database with spatial data management do not have theadvantage.This paper describes the characteristics of SVG spatial data, analysises the transform ofMapInfo to SVG and the problem of transformed image display. In addition also focuses onthe design and realization of spatial data based on SVG storage management, including themost important of spatial data storage management index structure. And proposed the useof area code quad tree for spatial indexing. The logical storage model of storage manage-ment consists of four parts of data: Structure symbol table, the basic primitive index tabledetails, primitive index table and attribute index table, which are the result of the parsingSVG document base on the characteristics of SVG.Based on the storage management model, and according to the image progressive trans-mission mechanism, in the query to achieve multi-resolution query. According to the quadtree natural capability of clustering space target. We can roughly considered spatial data atdifferent levels in quad tree have different resolution. And then, according to the level forprovide to users with different level of detail inquiry function.Above is the main work of this thesis. In the last, the paper takes experiments on dis-play effective using part of the map of Guangzhou. The experimental results show that theproposed model can effectively on manage SVG spatial data. The multi resolution strategiescan also be very good responses of various detailed level of map information.