An approach to efficient compression transmission schema of GML

GML, a geographic information coding standard, has been widely used in WebGIS, heterogeneous GIS data sharing, integration, and interoperation. However, its features of large amount of redundancy inherited from XML file structure and geographic information system make a serious obstacle in WebGIS applications. According to the characteristics of GML, a data stream-based compression algorithm GDSC ( GML data stream compression ) was given, which separated the GML into structure data and value data using “Draw Pattern”, replaced the structure data with dictionary table during the separation process, and compressed the structure data and value data respectively to increase compression rate. In order to reduce compression time, GDSC uses two sub-threads for compression, decompression and network transmission.