Analysis and application of the hierarchical metadata framework of the ISO 19115 standard

The emergence of WebGIS enables GIS users to acquire geographic data from others much easier than before. The rapid growth of OpenGIS technology not only boosts the internet-based exchange of geographic data, but also provides a solid framework for the interoperability of geographic data. It is, however, critical for users to have an unambiguous understanding about data before they can use it in the interested domains. This must depend on the correct modeling and interpretation of metadata and a world-wide metadata standard can certainly reduce the complexity during the data transfer. Being widely accepted by GIS communities, the ISO 19115 metadata standard provides a complete and flexible metadata structure to describe the different natures of geographic data. An interesting feature of the ISO 19115 standard is its hierarchical framework that can be used to describe different levels of geographic data, namely, dataset series-level, dataset-level, feature type-level, feature instance-level, attribute type-level, and attribute instancelevel. Though most of the current national standard only concentrate on the dataset-level metadata, we would like to further explore the possible applications of this hierarchical metadata framework in this paper. The analysis shows that the hierarchical framework can effectively reduce the duplicates during metadata creating process, as well as improve the interoperability of geographic features after transferred to clients.