Problems on the application of geographic information systems to urban environmental management

Geographic information systems(GIS)are a widely used tool in urban planning and management.More and more cities and deecision-makers require its attributes of promptness,precision and visualization.But the application of GIS in urban environmental management is still a new field and relevant researches are getting on tardily.As a subsystem of GIS,an urban environmental management geographic information system(UEMGIS0should be a complex multi-discipline and multi-objective tool to perform quantitative multi-dimension analysis and to transfer the results into an expression legible to an ordinary user.It should be a dynamic system of prompt functions based on upgradable databases,and be composed of many subsystems respectively specialized in items about water,air,waste and noise as well as relative standards and regulations.However, existing UEMGISs mostly rely on the basic GIS too much to design the actual requirements of applications and managements in themselves,and the unavailability of sufficient fundamental data has retarded their improvement.In the design of a UEMGIS,the standardization of data classification should be taken into consideration to make the data exchangeable and shareable among its subsystems and within every subsystemj,and the applicable error limits for input data should be defined in accordance with the user s required precision of data out.Data acquisition can be easy and quick if remote sensing,global positioning system(GPS)and other technologies are combined with GIS,Rapidly progressing information fechnologies have been giving a bright prospect for the melioration of UEMGIS that will have great potential and wide application in environmental conservation.