Topic maps for custom viewing of data

A Topic Map is a structured network of hyperlinks that points into an information pool. Topic Maps have an existence independent of the information pool and hence different Topic Maps can form different layers above the same information pool and provide us with different views of it. We explore the use of Topic Maps with the Unified Column Descriptor (UCD) scheme developed in the frame of the ESO-CDS data mining project. UCD, with its multi-tier hierarchical structure, categorizes parameters reported in tables and catalogs. By using Topic Maps we show how columns from different catalogs with similar but not identical descriptions could be combined. A direct application for the Virtual Observatory community is that of merging catalogs in order to generate customized views of data.