A Web-GIS Based Multiple SAR Image Database System

This paper briefly introduced to the characters of the satellite microwave Synthetic Aperture Radar (SAR) and its image storage technology, the domestic and foreign situation of remote sensing images storage in these days, and the basic conception and the last development trends of Web-GIS. Using for reference to the Landsat image distribution system– DNGP developed by UND, Taking advantage of open source software, a Web-GIS based SAR image database system is designed and completed.Based on the three tier Browser/Server (B/S) architecture model, the system is consisted by three function logic tiers: user service tier, business logic tier, and database service tier. The user service tier is client side and the business logic and database service tiers are server side. The characteristic of the system is fat server and thin client side. The server side has the functions of SAR image management, user management, assistant information, and management sub-system. SAR image management includes image preprocessing, image searching, display and download. User management includes user registration, user information modification, and user logging in. Assistant information includes help information, interrelated website link and news. The client side just has the functions of user request processing and results display.The system platform is all built by open source software. Operation system is Linux-Fedora Core 10. Client service tier used HTML, CSS, Javascript ,and Ajax, etc. The business logic tier is consisted of map server and web server, in which map server software is UMN Mapserver combining with GDAL, Proj, and FreeType, and the web server software is Apache. The database service tier is managed by PostgreSQL/PostGIS. PostGIS is a spatial extension of PostgreSQL to enable the geographic objects support, which provides the support for the SAR image storage and requests from business logic tier. All the open source software is in the restriction of Open GIS Consortium (OGC), which provides convenience for the data transaction and extension of the system. To meet the research requirement of the National Laboratory for Ocean Remote Sensing of MOE, the storage and management of multiple SAR image data are considered. Different SAR sensor has different data format, which give the inconvenience to the data storage and management. In order to solve this problem, different SAR image is converted into GeoTIFF format, and the image Geometric correction is finished at the same time. Nowadays, almost all of the service systems, around the world, for SAR data management targeting to the SAR data display and ordering don't provide multiple SAR data service. The Web-GIS based SAR database system– ORSI SAR presented by this thesis is running in the National Laboratory for Ocean Remote Sensing of MOE for test.