Representing in a database, a collection of items characterized by features. In a data processing system, determining a semantic space representations of the features across the collection. Each representation characterized by parameters and settings, and differing from each other by only one of: the value of one parameter, and the configuration of one setting. Determining, for each feature pair of a set of feature pairs, the relatedness of the first feature to the second feature in each semantic space representation. And representing the collection by the semantic space that provides the best aggregate relatedness across the set of feature pairs.