Design And Implementation Of GIS Subsystem In Urban Emergency Response System

With the development of human society, various types of hazardous incidents tend to be more frequent, complicated, specialization, and serious. And when these disasters occur, it often requires many duties, multiple departments, multi-level, cross-regional to defense, command and joint-operate unifiedly, and carry on the emergency rescue or emergency relief operations timely, orderly and efficiently. Under this premise, the construction of the city's emergency response system becomes particular imminence and necessary.Urban Emergency Response System is a platform of communications, information and command system, which uses the mordent integration technology to make multiple technologies such as wired communications, wireless communications, data communications, geographic information systems (GIS), Global Positioning System (GPS), network management, video surveillance, database, command scheduling and information processing combine with each other. Among them, GIS subsystems have functions of data collection and editing, data storage and management, spatial query and analysis etc, and it plays a crucial role in helping duty-departments to arranging best evacuation routes and rescue, or emergency routes, equipping with appropriate transportation, protecting public facilities and so on.This paper conducts a study on the GIS subsystem in the Urban Emergency Response System, adopts the secondary development model based on the GIS component Map Objects control to introduce detailedly the design and implement of GIS subsystem. Firstly, it analyzes and confirms the overall structure according to the needs and tasks of GIS subsystems and tasks, describes the functions of its main modules, and then the key functions of the system realization method is given. In search of the best path concerned, this system uses the classic Dijkstra's shortest path algorithm. By adding setups and barrier query functions to improve and perfect the algorithm. The system also combines with the GPS technology. via programme,the function can be achieved. Finally, this paper brings forward the proposed solutions to data management and maintenance of the GIS subsystems. Through introducing the design method which combine with the B/S structure and C/S structure, the basic geographic data and professional geographic data will be stored separately, so that GIS subsystem can save more hardware costs in terms of data storage and maintenance, and meet the various needs of different users.