Research On Spatial Data Quality Inspection And Assessment System

Spatial data quality issues is the basis of geographic information science issues. Spatial data collection, input, processing, conversion process, owing to the prevailing uncertainties, resulting in inaccurate of spatial data in the real world, data errors or error and therefore cannot meet the requirements of data, or cannot meet the needs of application data, which is the issue of the quality of spatial data. With the development of geographic information systems, as one of the key outputs of the GIS, spatial data products are widely used, of which quality management has become the key process in practice, and become the focus of the study. Spatial data quality management is a systematic process and quality inspection and evaluation of spatial data is the important part. For geographical information systems engineering practice, how to detect spatial data quality problems effectively and to evaluate spatial data quality objectively is the key factor to the scientific and effectiveness of data application and decision making.At present, the relevant departments and organizations issued a series of spatial data standards and regulations relating to quality management, to standardize the description of spatial data quality and guide spatial data quality assessment. In academia, for the detection and evaluation of spatial data, also shows several methods, and has achieved certain results in practice. However, quality inspection and evaluation of spatial data exists the following two major problems:one is the description of spatial data quality indicators proposed by the related standards are not uniform, and too abstract; the other is quality inspection and evaluation methods is subject to fragmentation. Therefore, a systematic study on the detection and evaluation of spatial data quality is needed, a more detailed and comprehensive spatial data quality metric should be given, combined with spatial data quality evaluation method and evaluation criteria, spatial data quality assessment system is established, which provide a reference for spatial data quality assessment. Based on the characteristics of spatial data, combined with the relevant spatial data quality standards, a set of spatial data quality evaluation index system is established and inspection and evaluation methods is relatively comprehensive and meticulous researched, a reference set of spatial data quality assessment system is built tentativly, and on the basis of the system, engineering solution of spatial data quality evaluation system is given.This paper focuses on content as:1) Research on spatial data quality evaluation. Study on spatial data quality standards in related fields, the spatial data quality indicators in SDTS, DIGEST, ISO 19113:2002, ISO 19157:2013, GB/T 21337-2008 and other related standards are given, which strengths and limitations are analyzed. Guided by the three characteristics of spatial data, based on the analysis of spatial data quality standards, combined with the work on data quality, the literature analysis method are used, the indicators proposed in the literature and standards is comprehensive compared, filtered, classified, graded, refined in accordance with characteristics of spatial data, the content of spatial data quality evaluation indicators is improved, and the spatial data quality indicator system is formated.2) Research on spatial data quality evaluation system. To spatial data quality assessment indicators for guidance, the connotation of the indicators is analysed, combined with spatial data production process, the evaluation criteria and the severity level of each index is proposed, and spatial data quality assessment framework is constructed. Combined the methods of detection of spatial data quality and evaluation proposed below, the spatial data quality assessment system is formated ultimately.3) Research on spatial data quality detection method. Study from three aspects: quality of spatial characteristics and relations, quality of feature attributes and relationships AND quality of the data schema. Comprehensive analysis of quality problems which may arise, and quality testing methods. In terms of data quality of spatial characteristics and relationships, based on the elements of geometry, feature is divided into three main types:points, lines, polygons, the quality problems of geometric characteristics of three types of feature themselves, as well as the problems of combination relations of three types of feature, a total of six kinds of spatial relations and the corresponding inspection methods are discussed. In terms of data quality of feature attributes and relations, according to the relational database structure, quality issues and inspection methods of attribute database instances, including for level of single field, multiple fields, single table (duplicates), multiple table are discussed. With respect to data schema quality problems, standardization problems of files, database name and structure aspects and their testing methods are proposed.4) Research of spatial data quality evaluation method. The Boolean variable, the number and ratio of three data quality metrics are discussed. Defects demerits, the weighted average method and fuzzy comprehensive evaluation method of three kinds of spatial data quality assessment methods and their advantages and limitations are given, and according to the quality evaluation principles, methods suggestions are given.5) Design and implementation of spatial data quality assessment system. Based on the evaluation of spatial data quality, guided by the idea of software engineering, the spatial data quality assessment system is designed and implementated, and system application examples are given.