Quality assessment and control of topographic data with applications to Hong Kong 1:1,000 i-series digital topo map

Abstract

Topographic data depicts natural and artificial features on the earth surface, and is often merged using various data sources in order to reflect the changes of real world entities. The quality of topographic data may affect by many factors, such as uncertainties in source materials, data processing and data usages, etc. Data quality assessment and control are vital in managing topographic data which allows both data providers and users to obtain quality information of their data. To assess the quality of topographic data, a clearly defined procedure is of major significant. This study analyses the principles of spatial data quality and proposes a procedure that includes four steps: a) create data quality objectives, b) establish data quality assessment plan, c) determine data quality result and d) report data quality result, for quality assessment. This procedure presents methods of obtaining internal and external quality requirements and introduces the principles of how to select appropriate methods for quality assessment. In Hong Kong, topographic data is derived from several data sources and receives frequent updates to reflect rapid changes of city and supports town planning, construction and other purposes. To ensure the data fulfilling both internal and external requirements, a robust data quality controlling system is required. This includes the establishment of data policy, data documentation, data quality life control, error handling and data dissemination. This study reviews the topographic data provided by Survey and Mapping Office (SMO) of the Hong Kong Special Administrative Region (HKSAR), and proposed a data quality controlling system that ensures the quality standards are maintained. An experimental study, using the Hong Kong 1:1,000 i-series digital topographic map, is conducted to demonstrate the underlying principles. The significance of this study lies on three aspects: a) to analyze current status of quality assessment and control of topographic data, b) to develop a quality assessment procedure for digital topographic data and c) to enhance the quality controlling system of 1:1,000 Hong Kong i-Series Topo Map.