Design And Development Of Web Geographic Information System Based On SVG

This dissertation analyses the storage structure of GIS data in the Oracle database,imports the geographic information from Mapinfo into Oracle database with the help ofOracle Spatial, proposes the categorization, layering, classification, pre-optimizationand storage for the Web GIS, completes the algorithm design of six major functionmodules, namely, the categorization layer classification of the geospatial data, thecoordinate transformation of different scale maps, the delamination storage of map data,the cutting and blanking of diagram elements at the visible windows, generation of roadnetwork according to the physical road data and multi-layer road navigation. With theapplication of Web technology and SVG to present geospatial information, Oracledatabase and Oracle Spatial for information management and Ajax and the JDOM forasynchronous generation of SVG Map and the stack for maps with different resolution,the author proposes a road node optimization algorithm similar to dichotomy, that is, asimple formula for discriminating two crossing roads and calculating the intersectioncoordinates, and designs an algorithm of road navigation such as path planning methodand the shortest path algorithms and so on.The GIS system studied in this dissertation has a number of advantages comparedwith conventional relational database. It uses Oracle structured database storage whichenables easier data storage and processing. The SVG for geographic data expands GISto Web GIS, allowing broader application region, shorter time span and shorter datadelivery cycle. The categorization, layering, classification, pre-optimization anddelamination storage of map data make possible the optimization and asynchronousgeneration of SVG Map upon demand. The utilization of Ajax and JDOM effectivelyreduces data traffic and improves customer experience by asynchronous data acquisitionupon demand.