The Study Of WebGIS's Data In Storing And Exchanging And Displaying Base On GML And SVG

The building-up of Information express highway have created condition for the information share of entire society。When Geographic information system and the Internet union, it have been improved in gaining, enjoying, announces and analyses of geographical feature space information. WebGIS becomes the hot spot that GIS studies nowadays with whose unique advantage. Realizing the data share one by one between system is difficult, realization is handled mutually on the net being also difficult since the data form has not united in the tradition GIS system, this can not satisfy the request that WebGIS develops.This thesis thinks that using XML technology to resolve these problems is feasible. We start with geographical feature data form first, the detailed analysis having been in progress to pattern in the GML3.0 white book announcing from OGC studies, expounded the main pattern structure and characteristic. On this basis, having realized GML-based geographical feature data code scheme , having testified GML-based data structural model is feasible.Secondly, this thesis has studied geographical feature data storing up way , the characteristic having analysed the pure XML data base mainly, the now available code scheme having compared . This thesis have brought forward one kind of the prefix code scheme with the fixing depths and width sub tree. According to this scheme, the operation of seeking and deleting and renewing all is simple, the problem solving about node depth and extent in tradition prefix code scheme has effect, have realized the unified code being in progress with fixed length data. This thesis has also explained XML data physics structure owing to being the code scheme's turn.. Moreover, this thesis has studied geographical feature data display , has analysed the conversion mode from GML to SVG mainly, have realized a GML document changing to SVG document with XSLT technology, have ascertained the feasibility building the WebGIS model judging by GML and SVG technology.Finally, this thesis reaches the following conclusion: The GIS base on GML will become younger generation GIS; the SVG technology will become the main current in the network image processes; under the condition that GML and SVG combine, WebGIS will be developed rapidly; owing to pure XML data base , the WebGIS system still waits for perfecting rise.