Incorporating visualized data completeness information in an open and interoperable GIS map interface

Successful data sharing is a critical challenge in the development of National Spatial Data Infrastructure, but the heterogeneity of geospatial data often impedes the correct use of distributed geospatial data. For example, although map interfaces have been widely used in GIS software, misunderstandings of the geospatial data illustrated in map interfaces may still produce unpredictable and unnoticeable risks. It is necessary for users to have a thorough understanding about the acquired data before they can make correct decisions. Based on the concept of valid extent and illustrated extent, this article has proposed a new model that incorporates visual aids of data completeness information in the GIS-based map interface by integrating metadata, Geography Markup Language, and cartographic knowledge. Compared to current GIS map interfaces, the introduced open format of distributed data and knowledge-based visual aids enables users to correctly interpret the illustrated results of the map interface in an interoperable and visualized way, such that users are always aware of the status of data completeness regarding the illustrated content of the map interfaces. Despite the fact that the discussions of this article are restricted to the issue of data completeness, the results have clearly indicated that such a visualized mechanism for data quality information should be included as a necessary component in the future OpenGIS distributed environment.