Dealing with Inconsistency between Digital Geographic Lines from Multi-data Sources in GIS
GIS中地理边线不一致性的处理

Data quality in spatial databases has been widely recognized as one of the most critical issues in GIS. Its key dimension is assessing data suitability, including data accuracy, precision, uncertainty, compatibility, consistency, completeness, availability and timeliness recorded in the data lineage. Over decades, data quality has attracted much attention in the GIS community, and various aspects of data quality have been investigated. However, research on topological consistency remains very weak though it is crucial for GIS spatial analysis. This paper proposes a new technique on handling topological consistencies as well as tracing error propagation. First, inconsistencies of digital geographic lines are categorized into two groups with or without equal numbers of vertexes. Then a standard formalizing approach has been introduced to make numbers of vertexes matched in the two poly-lines so that the generalized algorithm of node snapping can be used to remove the inconsistencies between the two poly-lines. Third, the equations of estimating the coordinates of the projected points and their errors in the process of standard formalization have been derived. The formulae of calculating the length, together with its accuracy, of new generated poly-lines have also been obtained. Finally, simple examples are provided to demonstrate how to implement the proposed technique into practice.