Data Quality Assessment And Control For Drainage Network GIS

With the development of informantion technology of urban drainage network, Geographic Information System (GIS) has been largely applied in many cities and become an effective tool in network information collection, management, update, analysis and treatment. The precise operation of GIS needs data of high quality as guarantee. However, limited by the inconsistent data condition of national drainage enterprises, such as deformity of infrastucture data, ineffective method of data collection and outdated managerial functions. It is necessary to make scientific assessment to date quality with effective method to ensure the correctness of data. It also has much realistic meaning to establish data quality control system.In this dissertation, the data quality assessment system for urban drainage network system is established for national cities. It also give technical support for drainage GIS from the viewpoint of data quality control. Firstable, this paper systematical analyses the data type, structure, management style, constant data error forms, reasons for data errors for drainage network GIS. The data quality assessment indicators are given according to the data requirement of drainage network, which includes precision, logistic coherence, data integrity, and expression rationality. Under these indicators, revelent accessorial assessment elements and reference items are given. The data quality error assessment standard and the flow chart are established according to the severity extent of data quality error with the aid of national related criterion of digital relief map products. Certain GIS data quality assessment methods are analysed and compared, such as Bug Marking, Hough Transforming and Control Circuit, especially comprehensive fuzzy assessment method and rough set assessment method, by use of the principle of Max Subjection Value of fuzzy mathematics and the predigestion of property decision-form of rough set theory. Both assessment methods use analytic hierarchy process method to confirm the weight of indicators. On the basis of above research, this dissertation discusses the GIS data quality control, which includes the methods of data quality control, principles. Related quality inspection methods and control system are set up. Finally the control effect is presented as a statistical report.In the end, a case of data quality assessment is given to describe the process of drainage network GIS data assessment. In this case, we can compare the feasibility of fuzzy assessment method and rough set assessment method in engineering. And it validates that the established GIS data quality assessment indicators and criterion can supply valuable reference for the maintaince of drainage network system and enhance system veracity.