Schema Mapper: A Visualization Tool for Incremental Semi-automatic Mapping-based Integration of Heterogeneous Collections into Archaeological Digital Libraries: The ETANA-DL Case Study

Schema mapping is a challenging problem. It has come to the fore in recent years; there are important applications like database schema integration and, more recently, digital library (DL) merging of heterogeneous data. With Schema Mapper we demonstrate a semi-automatic tool for schema integration that combines a novel visual interface with an algorithm-based recommendation engine. We use ETANA-DL, a digital library developed to support integration of data from Near Eastern archaeology sites, as we explore integrating new collections. Schemas are visualized as hyperbolic trees, thus allowing more schema nodes to be displayed at one time. Matches to selections are recommended to the user, which makes the mapping operation easier and faster. Once the user has completed the mapping operation, a wrapper (XSLT Style Sheet) is created automatically with the mappings which can be applied to transform source XML files into target XML files. Schema Mapper allows editing the target schema as part of the process of incremental enrichment of the target schema. This involves operations like adding a node as a child, renaming a node, and deleting a node. The changes to the target schema also can be logged to disk. Schema Mapper has been applied to integrate the Megiddo Collection successfully into the ETANA-DL Union Catalog. It also has been applied for data-level mapping, to ensure consistency of data representation to the users who access the information through services provided by the DL. Formative evaluation and a preliminary comparison with MapForce suggest that Schema Mapper may be usefully employed for schema mapping.