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In recent years , China and the global incidents continue to occur. How the scientific response to timely and properly handle emergencies is a major issue today our government must face , and geographic information systems ( GIS ) , three - dimensional visualization platform provides an effective solution for this issue pathways . Three-dimensional GIS platform because it can quickly browse , query spatial information and statistics , spatial analysis , special features , so it played a particularly important role in the government departments at all levels in decision - making and command public emergencies disposal . However, in recent years, with the DEM data acquisition technology continues to progress , the accuracy of its data to continuously improve . In particular, the SAR interferometry ( InSAR ) , laser radar ( LIDAR ) DEM data obtained , the accuracy of decimeter , even centimeter level . Such a massive , multi-scale DEM data , how their organizations , so that in the three - dimensional GIS platform fast display and browsing , and precise spatial analysis , is the key to determine the efficiency of three-dimensional GIS platform . This thesis, the key technologies of the DEM data organization , to build a global DEM data pyramid organizational model ; further study DEM data based on wavelet compression , lossless compression algorithm , the SPIHT coding combined with SevenZip data compression scheme ; further design based on multi-scale DEM Oracle Sapatial the database and use the C # language developed DEM warehousing software ; thus , saving storage and improve the transmission efficiency , to make it in the scheduling , storage, display and browsing speed performance have been greatly improvement, evaluation, reached the advanced level of the domestic three - dimensional GIS platform .
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