Merging data from a collection of Catalogues

Computer-assisted catalogue-merging utilities are the natural extension to manual methods used by astronomers to merge information from different catalogues in the pre-VO era. Recognizing which columns represent the same physical quantity is important not only to combine two or more tables, but it is of prime importance when the aim is to recognize sources with similar physical characteristics in an N-dimensional parameter space, ie, true data-mining. AstroGrid’s Data Federation Research Group studied the problem of merging columns from two or more sources (VOTables) based on their meta-data in order to merge the results of several cone-searches or from cross-match of catalogues. The results presented here are relevant in future usage within the VO.