The Research Of The Distributed Comprehensive Alarming System On WebGIS

Although the Police 3-in-1(110, 119 and 122)Comprehensive Alarming System has come into being for a long time,it fails to make full use of social security information system and other social resources to provide the support for the alarm processing,police deployment and scientific maneuvering. Therefore,it becomes an effective way to solve this problem by using spatial data with different scales and heterogeneous GIS to realize the interoperability of GIS applications.And it is also an important way to informatize and modernize police alarming and commanding system,and increase the policing efficiency.Combining the Web GIS,distributed computing system and distributed data sharing,this article proposes a Web Service-based system of distributed Web GIS,where the spatial data with different scales and heterogeneous GIS applications are more compatible,and the space information sharing and the interoperability of GIS applications are easily achieved.With a detailed analysis of the key technologies and programmers,we develop a Web GIS-based prototype of the distributed alarming and commanding system on the Linux platforms.The main ideas are as follows:First,this article introduces the history, status quo and tendency of police information system and alarming and commanding system.By analyzing the existing problems in current alarming and commanding system,it then introduces the status quo and trend of Web GIS.Secondly,this article investigates the advantages and disadvantages of different traditional distributed object-oriented technologies,such as, Microsoft's COM/DCOM,Object Management Group(OMG)'s CORBA,SUN's J2EE/EJB,and the features of different distributed Web GISs based on those three models.Then, by analyzing the shortcomings of traditional distributed object-oriented technologies in cross-platform interoperability,this article proposes a new distributed architecture of Comprehensive Alarming System based on Web Service with the consideration of status quo and trend of existing Comprehensive Alarming System.Thirdly,this article discusses the information sharing technologies in alarming and commanding system,such as,information integrating,the data conversing,databa- se middleware and interoperability, etc..Then,by comparing the characteristics of different methods,it proposes that the database middleware and interoperability should be applied in alarming and commanding system.Fourthly,with the analysis of mobile locating technology in GPS,Cell-ID,TOA, TDOA,AOA, EOTD,AFLT,A-GPS,GPSONE, etc.,this article applies a positioning technology for the new system. Besides,it also probes into conventional shortest path algorithm based on the hierarchical road networks and time frame,and proposes the shortest path algorithm for the new system.Finally,this article introduces the realization of Web GIS-based distributed prototype system, Web Service developing platform,GeoServer,and OpenLayers source-open development kit,and tests the solution proposed for the new system.